Exhibit 21
Subsidiaries of the Registrant
         
Subsidiary Name   State of Incorporation   Business Name
California Water Service Company
  California   California Water Service Company
CWS Utility Services
  California   CWS Utility Services
New Mexico Water Service Company
  New Mexico   New Mexico Water Service Company
Washington Water Service Company
  Washington   Washington Water Service Company
Hawaii Water Service Company, Inc.
  Hawaii   Hawaii Water Service Company
HWS Utility Services LLC
  Hawaii   HWS Utility Services
The Company and each of its subsidiaries operate in one business segment, the supply and distribution of water, and providing water-related services.

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