SEC Form 424B5 filed by H2O America

The information in this prospectus supplement and the accompanying prospectus is not complete and may be changed. This prospectus supplement and the accompanying prospectus are not an offer to sell these securities and are not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

 Filed Pursuant to Rule 424(b)(5)​

 Registration No. 333-282881​

Subject to completion, dated March 2, 2026

Preliminary prospectus supplement
(To Prospectus dated October 29, 2024)

$550,000,000

Common stock

We are offering $150,000,000 of shares of our common stock, par value $0.001 per share in this offering. In addition, the forward sellers referred to below are offering $400,000,000 of shares of our common stock. We expect to enter into forward sale agreements with each of JPMorgan Chase Bank, National Association, and Wells Fargo Bank, National Association, which are referred to as the “forward purchasers,” with respect to an aggregate of $400,000,000 of shares of our common stock. In connection with these forward sale agreements, the forward purchasers or their affiliates and/or agents, which are referred to in such capacity as the “forward sellers,” at our request, are borrowing from third parties and selling to the underwriters an aggregate of $400,000,000 of shares of our common stock. If in the good faith, commercially reasonable judgment of a forward purchaser, it or its affiliate is unable to borrow and deliver for sale on the anticipated closing date, a number of shares of our common stock underlying its forward sale agreement, or it or its affiliate would be unable to borrow, at a stock loan rate not greater than a specified rate, and deliver for sale on the anticipated closing date such number of shares of our common stock, or if certain other conditions to such forward seller’s obligations have not been satisfied, then we will issue and sell directly to the underwriters a number of shares of our common stock equal to the number of shares that such forward seller does not borrow and deliver.

We expect to receive proceeds from the sale of $150,000,000 of shares of common stock sold by us in this offering, but we will not initially receive any proceeds from the sale of the shares of our common stock sold by the forward sellers to the underwriters, except in certain circumstances described in this prospectus supplement, including the last sentence of the previous paragraph. Each forward sale agreement provides for settlement on a settlement date or dates to be specified at our discretion on or prior to March   , 2028. If we elect to cash settle all or a portion of the forward sale agreements, we may not receive any proceeds from such election, and we may owe cash to one or more of the forward purchasers. If we elect to net share settle all or a portion of the forward sale agreements, we will not receive any cash proceeds from such election, and we may owe shares of our common stock to one or more of the forward purchasers. See “Underwriting (Conflicts of Interest) — Forward Sale Agreements” for a description of the forward sale agreements.

We intend to use the net proceeds from this offering, together with the Debt Financing (as defined herein), to finance our proposed acquisition of Quadvest, L.P. and Quadvest Wholesale, LLC, or the “Quadvest Acquisition,” and to pay related fees and expenses. This offering is not conditioned on the consummation of the Quadvest Acquisition or the Debt Financing. The Quadvest Acquisition, if completed, will occur subsequent to the closing of this offering. If for any reason the Quadvest Acquisition does not close, then we expect to use the net proceeds from this offering for general corporate purposes, which may include acquisitions, capital expenditures, share repurchases or debt repayment, and we will not have any obligation to repurchase any or all of the shares of our common stock sold in this offering. See “Summary — The Quadvest Acquisition” and “Use of Proceeds.”

Our common stock is listed on the Nasdaq Global Select Market, or “Nasdaq,” under the symbol “HTO”. On February 27, 2026, the closing price for our common stock was $53.79 per share.

(1)

We expect to receive estimated net proceeds from the sale of shares of our common stock, before expenses, of approximately $      (or approximately $      if the underwriters’ option to purchase additional shares of our common stock is exercised in full, as described in detail below). We expect to receive net proceeds, before expenses, from the sale of our common stock of approximately $      upon full physical settlement of the forward sale agreements, which we expect to occur on or prior to March   , 2028. For purposes of calculating the estimated net proceeds to us, we have assumed that the forward sale agreements are fully physically settled based on the initial forward sale price of $      per share, which is equal to the price to the public per share less the underwriting discount shown above. The forward sale price is subject to adjustment pursuant to the forward sale agreements, and the actual proceeds, if any, will be calculated as described in this prospectus supplement. Although we expect to settle the forward sale agreements entirely by the full physical delivery of shares of our common stock to the forward purchasers in exchange for cash proceeds, we may, except in certain circumstances, elect cash settlement or net share settlement for all or a portion of our obligations under one or more forward sale agreements, in which case we may receive no cash proceeds or substantially less cash proceeds than is reflected in the above table upon settlement, or we may be required to deliver cash or shares of our common stock to the forward purchasers. See “Underwriting — Forward Sale Agreements” for a description of the forward sale agreements.

​

The underwriters have advised us and the forward sellers that they initially propose to offer the shares of our common stock to the public at the public offering price that appears on the cover page of this prospectus supplement and may offer shares to selected dealers at the public offering price minus a concession of up to $      per share. After the initial offering, the underwriters may change the public offering price and any other selling terms. The underwriters may offer and sell shares through certain of their affiliates.

We have granted the underwriters an option to purchase up to an additional $82,500,000 of shares of our common stock at a price of $       per share for a period of 30 days from the date of this prospectus supplement.

Investing in our common stock involves risks. See “Risk Factors” beginning on page S-10 to read about factors you should consider before buying shares of our common stock.

Neither the Securities and Exchange Commission, or the SEC, nor any state securities commission has approved or disapproved of these securities, or determined if this prospectus supplement and the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The underwriters expect to deliver the shares of our common stock against payment on or about March   , 2026.

Joint book-running managers

Prospectus supplement dated March   , 2026

 

TABLE OF CONTENTS

Prospectus supplement

Prospectus

 

S-i

 

You should rely only on the information contained in or incorporated by reference into this prospectus supplement, the accompanying prospectus or any related free writing prospectus prepared by or on behalf of us. Neither we nor any of the underwriters has authorized anyone to provide you with different or additional information. If anyone provides you with different or additional information, you should not rely on it. The information in this prospectus supplement, the accompanying prospectus or any free writing prospectus and the documents incorporated by reference herein and therein is accurate only as of the respective dates of such documents. Our business, financial condition, results of operations and prospects may have changed since those dates.

The distribution of this prospectus supplement and the accompanying prospectus and the offering of the shares of common stock in certain jurisdictions may be restricted by law. Persons into whose possession this prospectus supplement and the accompanying prospectus come should inform themselves about and observe any such restrictions. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer or solicitation by anyone in any jurisdiction in which such offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to any person to whom it is unlawful to make such offer or solicitation.

ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, including the documents incorporated by reference, which describes the specific terms of the common stock we are currently offering. The second part, the accompanying prospectus, gives more general information, some of which may not apply to the common stock we are currently offering in this prospectus supplement. See “Description of Capital Stock” in the accompanying prospectus. In the event that information in this prospectus supplement is inconsistent with information in the accompanying prospectus, you should rely on the information in this prospectus supplement.

You should not assume that the information contained in this prospectus supplement and the accompanying prospectus is accurate on any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus supplement and the accompanying prospectus are delivered on a later date. Information that we file with the Securities and Exchange Commission (the “SEC”) subsequent to the date on the cover of this prospectus supplement, and prior to the completion of this offering, will automatically update and supersede the information contained in this prospectus supplement and the accompanying prospectus. See “Where You Can Find More Information” and “Incorporation of Documents by Reference.”

The securities are being offered for sale only in jurisdictions where it is lawful to make such offers. The distribution of this prospectus supplement and the accompanying prospectus and the offering of the securities in other jurisdictions may also be restricted by law. Persons who receive this prospectus supplement and the accompanying prospectus should inform themselves about and observe any such restrictions. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer or solicitation by anyone in any jurisdiction in which such offer or solicitation is not authorized, in which the person making such offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to any person to whom it is unlawful to make such offer or solicitation. See “Underwriting (Conflicts of Interest)” in this prospectus supplement.

This prospectus supplement and the accompanying prospectus are part of an automatic shelf registration statement that we have filed with the SEC as a “well-known seasoned issuer” as defined in Rule 405 under the Securities Act. Under this shelf registration process, we may sell, at any time and from time to time, in one or more offerings, any of the securities described in the accompanying prospectus, including the common stock, up to an indeterminate amount, of which this offering is a part. In this prospectus supplement, we provide you with specific information about the terms of the common stock and this offering.

 

S-ii

 

Unless the context otherwise requires (including on the cover page and in “Summary — The Offering”) or as otherwise stated in “Risk Factors,” the terms the “Company,” “we,” “us,” “our” or similar terms and “H2O America” refers to H2O America, together with its consolidated subsidiaries, without giving effect to the Quadvest Acquisition, “Quadvest” refers collectively to Quadvest L.P. and Quadvest Wholesale, LLC, together with their consolidated subsidiaries, without giving effect to the Quadvest Acquisition, and “combined company” refers to us, after giving effect to the Quadvest Acquisition.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus supplement is part of a registration statement on Form S-3 that we have filed with the SEC. This prospectus supplement, filed as part of the registration statement, does not contain all the information set forth in the registration statement and its exhibits and schedules, portions of which have been omitted as permitted by the rules and regulations of the SEC. For further information about us, we refer you to the registration statement and to its exhibits and schedules. Certain information in the registration statement has been omitted from this prospectus supplement in accordance with the rules of the SEC.

We are subject to the reporting and information requirements of the Exchange Act and, in accordance therewith, file annual, quarterly and special reports, proxy statements and other information with the SEC. These documents may be accessed through the SEC’s electronic data gathering, analysis and retrieval system, or EDGAR, via electronic means, including the SEC’s home page on the Internet (www.sec.gov). Written requests for such copies should be directed to H2O America, 110 West Taylor Street, San Jose, CA 95110; telephone: (408) 279-7800, and our website is located at www.h2o-america.com. Information contained on our website is not incorporated by reference into this prospectus supplement and, therefore, is not part of this prospectus supplement or any accompanying prospectus.

We have the authority to designate and issue more than one class or series of stock having various preferences, conversion and other rights, voting powers, restrictions, limitations as to dividends, qualifications, and terms and conditions of redemption. See “Description of Capital Stock” in the accompanying prospectus. We will furnish a full statement of the relative rights and preferences of each class or series of our stock which has been so designated and any restrictions on the ownership or transfer of our stock to any shareholder upon request and without charge.

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to incorporate into this prospectus supplement information we file with the SEC in other documents. The information incorporated by reference is considered to be part of this prospectus supplement, and information we later file with the SEC will, subject to the next sentence, automatically update and supersede this information. We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act until all of the shares of common stock that are part of this offering have been sold or this offering has been terminated. The documents we have incorporated by reference are:

•

Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the SEC on February 26, 2026 (the “2025 Form 10-K”);

​

•

those portions of our definitive proxy statement on Schedule 14A, filed on April 1, 2025, that are incorporated by reference into our Annual Report on Form 10-K for the fiscal year ended December 31, 2024;

​

•

Current Report on Form 8-K filed with the SEC (other than information furnished rather than filed) on March 2, 2026; and

​

•

the description of our common stock contained in our Registration Statement on Form 8-A/A, filed with the SEC on November 15, 2016, and any amendment or report filed for the purpose of updating such description, including the description of capital stock contained in Exhibit 4.5 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, incorporated by reference into our 2025 Form 10-K.

​

 

S-iii

 

We incorporate by reference any future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act between the date of this prospectus supplement and the termination of the offering.

Notwithstanding the foregoing, unless specifically stated to the contrary, information that we furnish (and that is not deemed “filed” with the SEC) under Items 2.02 and 7.01 of any Current Report on Form 8-K, including the related exhibits under Item 9.01, is not incorporated by reference into this prospectus supplement or the registration statement of which this prospectus supplement is a part.

Any statement contained in a document that is incorporated by reference will be modified or superseded for all purposes to the extent that a statement contained in this prospectus supplement, the accompanying prospectus or in any other document that is subsequently filed with the SEC and incorporated by reference into this prospectus supplement, modifies or is contrary to that previous statement. Any statement so modified or superseded will not be deemed a part of this prospectus supplement, except as so modified or superseded. Since information that we later file with the SEC will update and supersede previously incorporated information, you should look at all of the SEC filings that we incorporate by reference to determine if any of the statements in this prospectus supplement or in any documents previously incorporated by reference have been modified or superseded.

Upon request, we will provide, without charge, to each person, including any beneficial owner, to whom a copy of this prospectus supplement is delivered, a copy of the documents incorporated by reference into this prospectus supplement but not delivered therewith. You may request a copy of these filings, and any exhibits we have specifically incorporated by reference as an exhibit in this prospectus supplement, at no cost by writing us at the following address: H2O America, 110 West Taylor Street, San Jose, CA 95110 or calling us at (408) 279-7800.

You may also access these documents, free of charge on the SEC’s website at www.sec.gov or on our website at www.h2o-america.com. Information contained on our website is not incorporated by reference into this prospectus supplement and you should not consider any information on, or that can be accessed from, our website as part of this prospectus supplement.

This prospectus supplement is part of a registration statement we filed with the SEC. We have incorporated exhibits into this registration statement. You should read the exhibits carefully for provisions that may be important to you.

You should rely only on the information incorporated by reference or provided in this prospectus supplement. We have not authorized anyone to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus supplement, the accompanying prospectus or in the documents incorporated by reference is accurate as of any date other than the date on the front of this prospectus supplement or those documents.

 

S-iv

 

CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING STATEMENTS

Statements contained or incorporated by reference in this prospectus supplement and the accompanying prospectus that are not statements of historical fact are “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements other than statements of historical fact included in this prospectus supplement and the accompanying prospectus are forward-looking statements made in good faith by us and are intended to qualify for the safe harbor from liability established by the Private Securities Litigation Reform Act of 1995. Forward-looking statements are based on management’s beliefs as well as current expectations, estimates, forecasts, and projections about H2O America and its subsidiaries and the industries in which H2O America and its subsidiaries operate and the beliefs and assumptions of management. Some of these forward-looking statements can be identified by the use of forward-looking words such as “believes,” “expects,” “projects,” “plans,” “estimates,” “anticipates,” “intends,” “seeks,” “plans,” “will,” “may,” “should,” “approximately,” or “strategy,” or the negative of those words or other comparable terminology. These forward-looking statements are only predictions and are subject to risks, uncertainties and assumptions that are difficult to predict. Therefore, actual results may differ materially and adversely from those expressed in any forward-looking statements. The accuracy of such statements is subject to a number of risks, uncertainties and assumptions including, but not limited to, the following factors:

•

the risks associated with the proposed transactions with Quadvest, including the risk of the proposed transactions not closing on the anticipated timeline, or at all, the ability to obtain required regulatory approvals, and the ability to successfully integrate Quadvest’s operations and realize the projected financial and other benefits of the proposed transactions;

​

•

the effect of water, utility, environmental and other governmental policies and regulations, including regulatory actions concerning rates, authorized return on equity, authorized capital structures, capital expenditures, per- and polyfluoroalkyl substances and other decisions;

​

•

changes in demand for water and other services;

​

•

unanticipated weather conditions and changes in seasonality including those affecting water supply and customer usage;

​

•

the effect of the impacts of climate change;

​

•

unexpected costs, charges or expenses;

​

•

our ability to successfully evaluate investments in new business and growth initiatives;

​

•

contamination of our water supplies and damage or failure of our water equipment and infrastructure;

​

•

the risk of work stoppages, strikes and other labor-related actions;

​

•

catastrophic events such as fires, earthquakes, explosions, floods, ice storms, tornadoes, hurricanes, terrorist acts, physical attacks, cyber-attacks, epidemic or similar occurrences;

​

•

changes in general economic, political, business and financial market conditions;

​

•

the ability to obtain financing on favorable terms, which can be affected by various factors, including credit ratings, changes in interest rates, compliance with regulatory requirements, compliance with the terms and conditions of our outstanding indebtedness, and general market and economic conditions; and

​

•

legislative and general market and economic developments.

​

Additional information concerning these and other risk factors is also contained in our 2025 Form 10-K, which is incorporated by reference herein, as updated by other reports and documents we file with the SEC. We do not undertake any obligation to update or revise the information contained in this prospectus supplement or the accompanying prospectus, any related free writing prospectus or the information included or incorporated by reference herein and therein, including the forward-looking statements, to reflect any event or circumstance that may arise after the date of this prospectus supplement.

 

S-v

 

S-1

 

S-2

 

S-3

 

(in thousands, except per share data)	​	​	For the Year Ended December 31, 2025				​
Pro Forma Combined Results of Operations:	​	​	​	​	​	​	​
Operating revenues	​	​	​	$	841,191	​	​
Total operating expenses	​	​	​	​	690,969	​	​
Operating income	​	​	​	​	150,222	​	​
Interest expense, other income and expense	​	​	​	​	(61,777)	​	​
Net income	​	​	​	$	82,628	​	​
Pro Forma Combined Per Share Data:	​	​	​	​	​	​	​
Earnings per share-basic	​	​	​	$	1.83	​	​
Earnings per share-diluted	​	​	​	$	1.82	​	​

(in thousands)	​	​	As of December 31, 2025				​
Pro Forma Combined Balance Sheet:	​	​	​	​	​	​	​
Utility plant and intangible assets	​	​	​	$	5,590,551	​	​
Less accumulated depreciation and amortization	​	​	​	​	1,120,232	​	​
Net utility plant	​	​	​	​	4,470,319	​	​
Total assets	​	​	​	$	5,704,928	​	​
Pro Forma Capitalization:	​	​	​	​	​	​	​
Total stockholder’s equity	​	​	​	$	2,069,270	​	​
Long-term debt (consolidated, excluding current maturities)	​	​	​	$	1,866,819	​	​
Total capitalization	​	​	​	$	3,936,089	​	​

S-4

 

​

​

​

For the Year Ended December 31,

​

(in millions)

​

​

2025

​

​

2024

​

​

2023

​

Operating income

​

​

​

$

177.5

​

​

​

​

$

170.5

​

​

​

​

$

149.4

​

​

Depreciation and amortization

​

​

​

​

115.3

​

​

​

​

​

112.9

​

​

​

​

​

105.9

​

​

Share based compensation expense

​

​

​

​

6.4

​

​

​

​

​

5.6

​

​

​

​

​

4.6

​

​

Other income/expense

​

​

​

​

—

​

​

​

​

​

—

​

​

​

​

​

2.3

​

​

(Gain)/loss on sale of real estate investments (a)

​

​

​

​

(0.3)

​

​

​

​

​

0.6

​

​

​

​

​

—

​

​

Expenses for mergers and acquisition related activities (b)

​

​

​

​

3.5

​

​

​

​

​

3.4

​

​

​

​

​

—

​

​

Taxes on (a) and (b) above

​

​

​

​

(0.9)

​

​

​

​

​

(1.1)

​

​

​

​

​

—

​

​

Cash taxes (paid)/received

​

​

​

​

(3.2)

​

​

​

​

​

0.6

​

​

​

​

​

(23.0)

​

​

Cash interest paid

​

​

​

​

(79.4)

​

​

​

​

​

(73.3)

​

​

​

​

​

(67.5)

​

​

Total funds from operations (FFO)

​

​

​

$

218.9

​

​

​

​

$

219.2

​

​

​

​

$

171.7

​

​

Total balance sheet debt

​

​

​

$

1,977.2

​

​

​

​

$

1,829.7

​

​

​

​

$

1,747.2

​

​

Adjustments:

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

Cash and liquid investments

​

​

​

​

(20.7)

​

​

​

​

​

(11.1)

​

​

​

​

​

(9.7)

​

​

Asset retirement obligations

​

​

​

​

3.3

​

​

​

​

​

3.4

​

​

​

​

​

3.3

​

​

Postretirement Benefit Obligation

​

​

​

​

—

​

​

​

​

​

—

​

​

​

​

​

12.2

​

​

Total debt

​

​

​

$

1,959.8

​

​

​

​

$

1,822.0

​

​

​

​

$

1,752.9

​

​

FFO / debt

​

​

​

​

11.2%

​

​

​

​

​

12.0%

​

​

​

​

​

9.8%

​

​

S-5

 

S-6

 

S-7

 

​

S-8

 

​

S-9

 

RISK FACTORS

An investment in our common stock involves a number of risks. See the risk factors described in our 2025 Form 10-K, which is incorporated by reference in this prospectus and any accompanying prospectus supplement or free writing prospectus. You should read this entire prospectus supplement and the accompanying prospectus and the information included or incorporated by reference herein and therein before making an investment decision. In particular, we urge you to consider carefully the factors set forth below and such risk factors as may be updated from time to time in our public filings. Any of these risks could materially and adversely affect our business, financial condition, results of operations and prospects and the actual outcome of matters as to which forward-looking statements are made in this prospectus supplement and the accompanying prospectus. As a result, the trading price of our common stock could decline, and you could lose some or all of your investment. While we believe we have identified and discussed below, in the accompanying prospectus and in the documents incorporated by reference herein and therein the material risks affecting our business, there may be additional risks and uncertainties that we do not presently know or that we do not currently believe to be material that may adversely affect our business, financial condition, results of operations and prospects in the future.

As used in this “Risk Factors” section, “we,” “us,” “our” or similar terms refer to H2O America, together with its consolidated subsidiaries, including, if the Quadvest Acquisition is consummated and following such consummation, Quadvest, L.P. and Quadvest Wholesale, LLC., together with their combined subsidiaries.

Risks Related to this Offering

Settlement provisions contained in each forward sale agreement subject us to risks if certain events occur, which could have an effect on H2O America’s results of operations and liquidity, and could cause the market price of our common stock to decline.

Each forward purchaser will have the right to accelerate each forward sale agreement to which it is a party (or, in certain cases, the portion thereof that it determines is affected by the relevant event) and require us to physically settle such forward sale agreement on a date specified by the relevant forward purchaser if:

•

in the good faith, commercially reasonable judgment of such forward purchaser, it or its affiliate is unable to borrow a number of shares of our common stock equal to the number of shares to be delivered by us upon physical settlement of its forward sale agreement or it or its affiliate is unable to borrow such number of shares at a rate equal to or less than an agreed maximum stock loan rate;

​

•

we declare any dividend or distribution on shares of our common stock payable in (i) cash in excess of a specified amount (other than an extraordinary dividend), (ii) securities of another company, or (iii) any other type of securities (other than our common stock), rights, warrants or other assets for payment (cash or other consideration) at less than the prevailing market price, as reasonably determined by such forward purchaser;

​

•

certain ownership thresholds applicable to such forward purchaser are exceeded;

​

•

an event is announced that, if consummated, would result in an extraordinary event (as defined in the forward sale agreements), including, among other things, certain mergers and tender offers, as well as certain events such as a delisting of our common stock (each as more fully described in the forward sale agreements); or

​

•

certain other events of default or termination events occur, including, among other things, any material misrepresentation made by us in connection with our entry into a forward sale agreement, our bankruptcy (except as described below) or certain changes in law (each as more fully described in the forward sale agreements).

​

A forward purchaser’s decision to exercise its right to accelerate a forward sale agreement to which it is a party (or, in certain cases, the portion thereof that it determines is affected by the relevant event) will be made irrespective of our interests, including our need for capital. In such cases, we could be

 

S-10

 

required to issue and deliver shares of our common stock under the physical settlement provisions of that particular forward sale agreement irrespective of our capital needs, which would result in dilution to our earnings per share and return on equity, and may adversely affect the market price of our common stock. In addition, upon certain events of bankruptcy or insolvency related to us, each forward sale agreement will automatically terminate without further liability of either party. Following any such termination, we would not issue any shares of our common stock or receive any proceeds pursuant to the forward sale agreements.

Each forward sale agreement provides for settlement on a settlement date or dates to be specified at our discretion on or prior to March   , 2028. Each forward sale agreement will be physically settled by delivery of shares of our common stock, unless we elect to cash settle or net share settle such forward sale agreement. Upon physical settlement or, if we so elect, net share settlement of a particular forward sale agreement, delivery of shares of our common stock in connection with such physical settlement or (to the extent we are obligated to deliver shares of our common stock) net share settlement will result in dilution to our earnings per share and return on equity, and may adversely affect the market price of our common stock. If we elect cash settlement or net share settlement with respect to all or a portion of the shares of our common stock underlying a particular forward sale agreement, we expect that the relevant forward purchaser (or an affiliate thereof) will purchase a number of shares of our common stock necessary to satisfy its or its affiliate’s obligation to return the shares of our common stock borrowed from third parties in connection with the related sales of shares of our common stock under that forward sale agreement and, upon net share settlement, its obligation to deliver shares to us, if applicable. If the market value of shares of our common stock during the relevant valuation period under the particular forward sale agreement is above the applicable forward sale price, in the case of cash settlement, we would be obligated to pay the relevant forward purchaser under that particular forward sale agreement an amount in cash equal to the difference multiplied by the number of shares of our common stock underlying that particular forward sale agreement subject to cash settlement or, in the case of net share settlement, we would be obligated to deliver to the relevant forward purchaser a number of shares of our common stock having a value equal to the difference multiplied by the number of shares of our common stock underlying that particular forward sale agreement subject to net share settlement. Thus, we could be responsible for a potentially substantial cash payment or share delivery obligation. See “Underwriting (Conflicts of Interest) — Forward Sale Agreements” in this prospectus supplement for information on the forward sale agreements.

In addition, the purchase of shares of our common stock in connection with the relevant forward purchaser or its affiliate unwinding its hedge positions could cause the market price of our common stock to increase over such time (or reduce or prevent a decrease over such time), thereby increasing the amount of cash we would owe to the relevant forward purchaser (or decreasing the amount of cash that the relevant forward purchaser would owe us) upon a cash settlement of the relevant forward sale agreement or increasing the number of shares of our common stock we would be obligated to deliver to the relevant forward purchaser (or decreasing the number of shares of our common stock that the relevant forward purchaser would be obligated to deliver to us) upon net share settlement of the relevant forward sale agreement. We will not be able to control the manner in which the forward purchasers unwind their hedge positions.

The forward sale price that we expect to receive upon physical settlement of the forward sale agreements is subject to adjustment on a daily basis based on a floating interest rate factor equal to the overnight bank funding rate less a spread and will be decreased based on amounts related to expected dividends on shares of our common stock during the term of such forward sale agreement. If the overnight bank funding rate is less than the spread on any day, the interest rate factor will result in a daily reduction of the forward sale price for such day. The forward sale price will also be subject to decrease if the cost to a forward seller of borrowing the number of shares of our common stock underlying the applicable forward sale agreement exceeds a specified amount.

In certain bankruptcy or insolvency events, the forward sale agreements will automatically terminate, and we would not receive the expected proceeds from the forward sales of our common stock.

If we institute or consent to, or an appropriate regulatory or other authority institutes against us, a proceeding seeking a judgment in bankruptcy or insolvency or any other relief under any bankruptcy or

 

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insolvency law or other similar law affecting creditors’ rights or if we or such authority presents a petition for our winding up or liquidation or we consent to such a petition, each forward sale agreement will automatically terminate. If a forward sale agreement so terminates, we would not be obligated to deliver to the relevant forward purchaser any shares of our common stock not previously delivered (or for which physical settlement has not been elected), and the relevant forward purchaser would be discharged from its obligation to pay the forward sale price per share in respect of any shares of our common stock not previously settled (or for which physical settlement has not been elected). Therefore, to the extent there are any shares of our common stock with respect to which we have not elected to physically settle under a forward sale agreement at the time of the institution of or consent to any such bankruptcy or insolvency proceedings or any such petition, we would not receive the forward sale price per share in respect of those shares of our common stock.

Our shareholders may experience dilution as a result of this offering and they may experience further dilution if we issue additional common stock.

The issuance of any common stock by us pursuant to a forward sale agreement upon physical settlement or net share settlement thereof, or in lieu of the forward sellers selling our common stock to the underwriters, will have a dilutive effect on our earnings per share.

Any additional future issuances of our common stock will reduce the percentage of our common stock owned by investors purchasing shares in this offering who do not participate in future issuances. In most circumstances, shareholders will not be entitled to vote on whether or not we issue additional common stock. In addition, depending on the terms and pricing of an additional offering of our common stock, our shareholders may experience dilution in both the book value and fair value of their shares.

Future sales of shares of our common stock or preferred stock could adversely affect the market price of our common stock.

Future sales of substantial amounts of our common stock in the public market following this offering, whether by us or our existing shareholders, or the perception that such sales could occur, may adversely affect the market price of our common stock, which could decline significantly. Sales by our existing shareholders might also make it more difficult for us to raise equity capital by selling new common stock at a time and price that we deem appropriate. We may also raise capital by issuing shares of preferred stock that have super voting, special approval, dividend or other rights or preferences that are senior to our common stock. Shares of preferred stock may also be convertible into shares of our common stock, which may dilute the value of our common stock. Our board of directors may authorize the issuance of preferred stock from time to time in one or more series, without shareholder approval. See “Description of Capital Stock” beginning on page 13 of the accompanying prospectus.

The price of our common stock may fluctuate significantly.

The market price of our common stock may fluctuate significantly. You may not be able to resell your shares at or above the offering price due to fluctuations in the market price of our common stock caused by changes in H2O America’s operating performance or prospects and other factors, including broad market fluctuations. Some specific factors that may have a significant effect on the market price of our common stock, in addition to those set forth under “Cautionary Statement Concerning Forward-Looking Statements” in this prospectus supplement, include:

•

actual or anticipated variations in H2O America’s operating results or future prospects;

​

•

the public’s and the financial markets’ reaction to H2O America’s press releases, its other public announcements and our filings with the SEC;

​

•

strategic actions by H2O America or its competitors, such as acquisitions, dispositions or restructurings;

​

•

changes in accounting standards, policies, guidance, interpretations or principles;

​

•

price and volume fluctuations in the overall equity capital markets from time to time;

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•

adverse conditions in the financial markets or general economic conditions, including those resulting from war, incidents of terrorism and responses to such events;

​

•

future sales of common stock by us or our directors or executive officers; and

​

•

changes in securities analyst estimates, projections or recommendations regarding H2O America or our common stock or other securities, other comparable companies or their securities, or the water and wastewater industries generally.

​

Risks Related to the Quadvest Acquisition

This offering is not conditioned on the consummation of the Quadvest Acquisition.

This offering is not conditioned on the consummation of the Quadvest Acquisition. Accordingly, by purchasing our common stock, you are investing in H2O America on a stand-alone basis, without the business of Quadvest, in the event that we do not consummate the Quadvest Acquisition. Although certain information included in this prospectus supplement generally assumes consummation of the Quadvest Acquisition, the Quadvest Acquisition may not be consummated on the terms described herein or at all. The consummation of the Quadvest Acquisition is subject to conditions, which may or may not be satisfied. If for any reason the Quadvest Acquisition does not close, then we expect to use the net proceeds from this offering for general corporate purposes, which may include acquisitions, share repurchases or debt repayment, and we will have no obligation to repurchase any of our shares of common stock sold in this offering. See “Use of Proceeds.”

Failure to obtain financing for the Quadvest Acquisition on favorable terms or at all could negatively impact the operating results and financial condition of H2O America.

We intend to finance the Quadvest Acquisition with net proceeds from this offering and the Debt Financing, and there is no guarantee that we will be able to secure such financing to complete the Quadvest Acquisition on favorable terms, or at all. The incurrence of additional indebtedness could adversely affect H2O America’s financial condition, results of operations or cash flows. Additionally, equity financings may result in dilution to our existing stockholders, and debt financings may contain covenants that restrict the actions of H2O America and its subsidiaries. Furthermore, any downgrade in H2O America’s credit ratings by rating agencies may negatively impact the market value and liquidity of H2O America’s debt and equity securities.

We may take on substantial additional indebtedness to finance the Quadvest Acquisition, which will decrease our business flexibility and increase our borrowing costs.

In addition to this offering, we expect to finance the remaining portion of the purchase price of the Quadvest Acquisition with net proceeds from up to $140 million of Debt Financing, which may include the issuance of $100 million of private placement notes of the Company and other debt financing. If and to the extent that this offering is not completed or is completed for less proceeds than anticipated, we would expect to fund any shortfall with proceeds of the issuance of common stock under our at-the-market offering program or additional Debt Financing. As a result of the Debt Financing, we will increase our indebtedness substantially as compared to our indebtedness prior to the Quadvest Acquisition. Any financial covenants we agree to in connection with such indebtedness and higher debt-to-equity ratio in comparison to that of our recent historical basis will have the effect, among other things, of reducing our flexibility to respond to changing business and economic conditions and increasing borrowing costs. In addition, the actual terms and conditions of such indebtedness may not be favorable to us, and as such, could further increase the cost of the Quadvest Acquisition, as well as the overall burden of such indebtedness upon us and our business flexibility. Unfavorable terms in the Debt Financing may also adversely affect our business, financial condition, results of operations and prospects.

 

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USE OF PROCEEDS

We estimate that the net proceeds that we receive from the sale of shares of our common stock we are offering and selling, after deducting the underwriting discount and commissions and before expenses payable by us, will be approximately $     (or $     if the underwriters’ option to purchase additional shares is exercised in full). We will not initially receive any proceeds from the sale of the shares of common stock offered by the forward sellers in this offering, unless an event occurs that requires us to sell our common stock to the underwriters in lieu of the forward sellers selling our common stock to the underwriters as further described elsewhere in this prospectus supplement. In each case, we intend to use all net proceeds we receive from any such sales for the same purposes described below.

At an initial forward sale price of $      per share (which is the price at which the underwriters have agreed to buy the shares of common stock offered hereby), we expect to receive net proceeds, before expenses, of approximately $      million, subject to the price adjustment and other provisions of the forward sale agreements, in the event of full physical settlement of the forward sale agreements, which we expect to occur on or prior to March   , 2028. For purposes of calculating the proceeds to us upon settlement of the forward sale agreements, we have assumed that each forward sale agreement is physically settled based upon the initial forward sale price of $      on the effective date of the forward sale agreements, which will be March   , 2026. The actual proceeds from the forward sales are subject to the final settlement of the forward sale agreements. The forward sale price that we expect to receive upon physical settlement of a forward sale agreement is subject to adjustment on a daily basis based on a floating interest rate factor equal to the overnight bank funding rate less a spread and will be decreased based on amounts related to expected dividends on shares of our common stock during the term of such forward sale agreement. If the overnight bank funding rate is less than the spread on any day, the interest rate factor will result in a daily reduction of the forward sale price for such day. If the overnight bank funding rate decreases substantially prior to the settlement of a forward sale agreement, we may receive less than the initial forward sale price per share upon physical settlement of such forward sale agreement. Although we expect to settle each forward sale agreement entirely by the physical delivery of shares of our common stock in exchange for cash proceeds, we may, except in certain circumstances, elect cash settlement or net share settlement for all or a portion of our obligations under each forward sale agreement. See “Underwriting (Conflicts of Interest) — Forward Sale Agreements” for a description of the forward sale agreements.

We currently intend to elect full physical settlement of each forward sale agreement and to use the net proceeds, if any, that we would receive upon settlement of the forward sale agreements (or otherwise pursuant to this offering), together with the net proceeds from the Debt Financing, to finance the Quadvest Acquisition and to pay related fees and expenses and for general corporate purposes, which may include acquisitions, capital expenditures, share repurchases or debt repayment.

However, this offering is not conditioned on the consummation of the Quadvest Acquisition or the Debt Financing. If for any reason the Quadvest Acquisition does not close, then we expect to use the net proceeds from this offering for general corporate purposes, which may include acquisitions, capital expenditures, share repurchases or debt repayment, and we will not have any obligation to repurchase any or all of our shares of common stock sold in this offering. See “Summary — Financing of the Quadvest Acquisition” and “Risk Factors — Risks Related to the Quadvest Acquisition.”

 

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CERTAIN ACCOUNTING MATTERS

Before any issuance of our common stock upon settlement of a forward sale agreement, the forward sale agreement will be reflected in our diluted earnings per share calculations using the treasury stock method. Under this method, the number of shares of common stock used in calculating diluted earnings per share is deemed to be increased by the excess, if any, of the number of shares that would be issued upon physical settlement of the forward sale agreement over the number of shares that could be purchased by us in the market (based on the average market price during the period) using the proceeds receivable upon settlement (based on the adjusted forward sale price at the end of the reporting period). Consequently, prior to physical or net share settlement of a forward sale agreement and subject to the occurrence of certain events, we anticipate there will be no dilutive effect on our earnings per share except during periods when the average market price of our common stock is above the per share adjusted forward sale price. However, if we decide to physically or net share settle a forward sale agreement, delivery of shares of our common stock on any physical or net share settlement of the forward sale agreement will result in an increase in the number of shares of our common stock used in calculating diluted earnings per share, potentially resulting in a decrease in diluted earnings per share under GAAP.

 

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CAPITALIZATION

The following table sets forth our cash and cash equivalents and capitalization as of December 31, 2025 on:

•

an actual basis;

​

•

an as adjusted basis giving effect to this offering (assuming full physical settlement of the forward sale agreements and no exercise of the underwriters’ option to purchase additional shares), but without giving effect to the application of the net proceeds thereof or the Quadvest Acquisition and any related Debt Financing; and

​

•

a pro forma basis giving effect to this offering (assuming full physical settlement of the forward sale agreement and no exercise of the underwriters’ option to purchase additional shares), the expected Debt Financing and the Quadvest Acquisition.

​

You should read this table in conjunction with “Use of Proceeds” appearing elsewhere in this prospectus supplement, our audited financial statements and the accompanying notes, which are incorporated by reference into this prospectus supplement from our 2025 Form 10-K. See “Unaudited Combined Pro Forma Financial Information.”

This offering is not contingent upon either the Quadvest Acquisition or the Debt Financing reflected in the pro forma adjustments included in the following information.

(1)

Our long-term indebtedness includes certain financings by our subsidiaries in the fiscal year ended December 31, 2025, including $55.0 million of private placement notes of SJWC due 2055, $60.0 million of private placement notes of CWC due 2055, $40.0 under a promissory note issued to TWC by a national cooperative bank due 2055 and $25.0 million under a promissory note issued to MWC by a national cooperative bank due 2055. In addition to our long-term indebtedness, as of December 31, 2025, we had short-term indebtedness under lines of credit of $86.8 million. As of December 31, 2025, we and our subsidiaries had unsecured bank lines of credit allowing for aggregate short-term borrowings of up to $370.0 million, of which $50.0 million was available to H2O America, $165.0 million was available to SJWC, $80.0 million was available to CWC, $25.0 million was available to MWC and $30.0 million was available to TWC under a single line of credit, $10.0 million was available to SJWC under a single line of credit and $10.0 million was available to Connecticut Water Service, Inc. under a single line of credit. As of December 31, 2025, H2O America and its subsidiaries had available unused short-term bank lines of credit totaling approximately $283.2 million.

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(2)

We expect to incur Debt Financing to fund a portion of the Quadvest Acquisition. See “Summary —  Financing of the Quadvest Acquisition.”

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DIVIDEND POLICY

We have paid regular quarterly cash dividends on shares of our common stock for many years. We currently expect to maintain at least our current dividend per share rates following the Quadvest Acquisition.

However, any future determination regarding dividend or distribution payments will be at the discretion of the combined company’s board of directors and subject to applicable limitations under Delaware law, market conditions and other factors. Please refer to the information under the heading “Risk Factors” in our 2025 Form 10-K, which is incorporated by reference in this prospectus supplement and the accompanying prospectus.

 

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UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

The unaudited pro forma condensed combined financial information presented herein is prepared in accordance with Article 11 of Regulation S-X of the Securities Exchange Act of 1934 and should be read in conjunction with the accompanying notes. The following unaudited pro forma condensed combined financial information combines the historical consolidated financial position and results of operations of H2O America and the historical consolidated financial position and results of operations of Quadvest, L.P. and Quadvest Wholesale, LLC (collectively “Quadvest”) after giving effect to the Quadvest Acquisition as further described in Note 1. Description of the Transactions and Basis of Presentation and the pro forma effects of certain assumptions and adjustments described in “Notes to the Unaudited Pro Forma Condensed Combined Financial Information” below. The unaudited pro forma condensed combined financial information has been prepared to give effect to the following (collectively, the “Transactions”):

•

Application of the acquisition method of accounting under the provisions of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 805, Business Combinations (“ASC 805”) where the assets and liabilities of Quadvest will be recorded by H2O America at their respective fair values as of the closing date of the Quadvest Acquisition (“Closing Date”);

​

•

Preliminary adjustments to conform the financial statement presentation of Quadvest to those of H2O America;

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•

The Financing Transactions, as described and defined below; and

​

•

Adjustments to reflect estimated acquisition-related costs of the Quadvest Acquisition.

​

The unaudited pro forma condensed combined financial information and related notes are derived from the historical financial statements of H2O America and Quadvest, and should be read in conjunction with the following financial statements and accompanying notes:

•

The historical audited consolidated financial statements of H2O America as of and for the year ended December 31, 2025, included in its Annual Report on Form 10-K (the “2025 Form 10-K”) filed with the Securities and Exchange Commission (“SEC”) on February 26, 2026; and

​

•

The historical audited consolidated financial statements of Quadvest as of and for the year ended December 31, 2025 and the related notes, which are included in H2O America’s Current Report on Form 8-K filed with the SEC on March 2, 2026.

​

The unaudited pro forma condensed combined financial information should also be read together with other financial data included elsewhere in, or incorporated by reference into, this prospectus supplement

The unaudited pro forma condensed combined balance sheet as of December 31, 2025, gives pro forma effect to the Transactions as if they had been consummated on December 31, 2025. The unaudited pro forma condensed combined statements of operations for the year ended December 31, 2025 give pro forma effect to the Transactions as if they had been consummated on January 1, 2025.

The unaudited pro forma condensed combined financial information has been prepared using the acquisition method of accounting pursuant to the provisions of ASC 805, whereby H2O America is considered the accounting acquirer. The consideration transferred will be allocated to the identifiable assets acquired and liabilities assumed based upon their estimated fair values as of the Closing Date, and any excess value of the consideration transferred over the acquired net assets will be recognized as goodwill. The assets and liabilities of Quadvest have been measured based on preliminary estimates using assumptions that H2O America believes are reasonable, based on information that is currently available. The unaudited pro forma condensed combined financial information is based on preliminary accounting conclusions subject to potential revision and, as a result, has been presented for illustrative purposes only and is not necessarily indicative of the financial position and results of operations that would have been achieved had the Transactions occurred on the dates indicated.

The unaudited pro forma condensed combined financial information appearing below is based on available preliminary information and certain assumptions that are believed to be reasonable as of the

 

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date of this prospectus supplement and also does not consider any potential effects of changes in market conditions on revenues or expense efficiencies, among other factors. Future results may vary significantly from the results reflected because of various factors, including those discussed in the sections titled “Forward-Looking Statements,” “Risk Factors” and the consolidated audited and unaudited financial statements of H2O America and Quadvest included, or incorporated by reference, in this prospectus supplement. In addition, as explained in more detail in the accompanying notes, the preliminary allocation of the pro forma purchase price reflected in the unaudited pro forma condensed combined financial information is subject to adjustment and may vary significantly from the actual purchase price allocation that will be recorded upon completion of the Quadvest Acquisition.

 

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UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET
As of December 31, 2025
(in thousands)

 

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See the accompanying notes to the Unaudited Pro Forma Condensed Combined Financial Information.

 

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UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS
As of December 31, 2025
(in thousands)