SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN

Published on March 25, 2003



Exhibit 10.23

CALIFORNIA WATER SERVICE COMPANY
SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN

AMENDMENT NO. 3

WHEREAS, California Water Service Company (the "Company") maintains the
California Water Service Company Supplemental Executive Retirement Plan (the
"Plan"), for the benefit of a select group of the Company's management and
highly compensated employees;

WHEREAS, the Board of Directors has amended the Plan to decrease the
number of years required for full vesting in the Plan from 35 years to 15 years;

NOW, THEREFORE, effective as of January 1, 2003, the Plan is hereby
amended as follows:

3. The table in Section 5.1(a) of the Plan used to determine
participants' "Normal Retirement Benefits" under the Plan is restated to read as
follows:

Years of Service Percentage

5 11.25%
6 16.13
7 21.00
8 25.88
9 30.75
10 34.63
11 40.50
12 45.38
13 50.25
14 55.13
15 60.00



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