Use these links to rapidly review the document TABLE OF CONTENTS Table of Contents Form 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file No. 1-13883 CALIFORNIA WATER SERVICE GROUP (Exact name of registrant as specified in its charter) Delaware 77-0448994 (State or Other Jurisdicti ...