UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

Current Report Pursuant to Section 13 or 15(d) of

The Securities Exchange Act of 1934

Date of Report (date of earliest event reported): May 11, 2021

CALIFORNIA WATER SERVICE GROUP

(Exact name of Registrant as Specified in its Charter)

(408) 367-8200

(Registrant’s telephone number, including area code)

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨     Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨     Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨     Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨     Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Indicate by check mark whether the registrant is an emerging growth company as defined by Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth 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. ¨

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

On May 11, 2021, Cal Water completed the sale and issuance (the “Offering”) to the public of $130 million principal amount of its 2.87% First Mortgage Bonds due May 11, 2051, Series ZZZ and $150 million principal amount of its 3.02% First Mortgage Bonds due May 11, 2061, Series 1 (collectively, the “Bonds”) pursuant to a Bond Purchase Agreement, dated February 25, 2021. BofA Securities, Inc. and U.S. Bancorp Investments, Inc. acted as joint lead placement agents for the Offering.

Interest on the Bonds will accrue semi-annually and be payable in arrears on May 11 and November 11 of each year, commencing November 11, 2021. The Bonds rank equally with all of Cal Water’s other First Mortgage Bonds and are secured by liens on Cal Water’s properties, subject to certain exceptions and permitted liens.

Cal Water used the net proceeds from the sale of the Bonds to refinance existing indebtedness and for general corporate purposes, as set forth in California Public Utilities Code Section 817.

The Bonds were not registered under the Securities Act of 1933 and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements. This report is neither an offer to sell nor a solicitation of an offer to buy any of the Bonds.

The foregoing description of the Bonds is qualified in its entirety by reference to the full terms and conditions of the Sixty-Third Supplemental Indenture dated as of May 11, 2021, which is filed as Exhibit 10.1 hereto and incorporated by reference.

Item 9.01. Financial Statements and Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.