AMERICAN STATES WATER CO

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

for the quarterly period ended March 31, 2026

or

for the transition period from to

Commission file number 001-14431

American States Water Company

(Exact Name of Registrant as Specified in Its Charter)

(909)394-3600

(Registrant’s Telephone Number, Including Area Code)

Not Applicable

(Former Name, Former Address and Former Fiscal Year, if Changed Since Last Report)

Securities registered pursuant to Section 12(b) of the Securities Exchange Act of 1934:

Commission file number 001-12008

Golden State Water Company

(Exact Name of Registrant as Specified in Its Charter)

(909)394-3600

(Registrant’s Telephone Number, Including Area Code)

Not Applicable

(Former Name, Former Address and Former Fiscal Year, if Changed Since Last Report)

Securities registered pursuant to Section 12(b) of the Securities Exchange Act of 1934:

Indicate by check mark whether Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Indicate by check mark whether Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or such shorter period that the Registrant was required to submit such files).

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

American States Water Company

Golden State Water Company

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.¨

Indicate by check mark whether Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act)

As of May 5, 2026, the number of common shares, no par value (“Common Shares”) outstanding of American States Water Company was 39,192,653. As of May 5, 2026, all of the 178.3836 outstanding shares of common stock, no par value, of Golden State Water Company were owned by American States Water Company.

Golden State Water Company meets the conditions set forth in General Instruction (H)(1)(a) and (b) of Form 10-Q and is therefore filing this Form, in part, with the reduced disclosure format for Golden State Water Company.

and

FORM 10-Q

INDEX