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):    September 21, 2005 
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                         CALIFORNIA WATER SERVICE GROUP
                         ------------------------------
             (Exact name of registrant as specified in its charter)



          Delaware                    1-13883                77-0448994
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(State or other jurisdiction       (Commission            (I.R.S. Employer
     of Incorporation)             File Number)          Identification No.)


      1720 North First Street, San Jose, CA.                   95112   
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     (Address of principal executive offices)                (Zip Code)


Registrant's telephone number, including area code        1-408-367-8200 
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                                 Not Applicable
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          (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 (see General Instruction A.2. below):

[ ] 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))



Item 1.01 Entry into a Material Definitive Agreement

Effective  September 21, 2005,  California Water Service Company, a wholly owned
subsidiary of the  registrant,  entered into an agreement with Kern County Water
Agency to obtain  treated  water for the Company's  operations.  The term of the
agreement is to January 1, 2035 or until the  repayment  of the  Agency's  bonds
(described  below).  This  agreement  supersedes  the prior  agreement with Kern
County Water Agency,  as amended,  dated June 13, 1974. The following summary of
the  agreement  is  qualified  in its  entirety by  reference to the text of the
agreement,  which is  attached as Exhibit  10.1 to this report and  incorporated
herein by reference.

The  agreement  obligates  the Company to  purchase  20,500 acre feet of treated
water per year,  which is an  increase  from the  11,500  acre feet in the prior
agreement. There are no other parties to the agreement between Cal Water and the
Agency.  The Company is obligated to pay the Capital  Facilities  Charge and the
Treated Water Charge regardless of whether it can use the water in its operation
and is  obligated  for these  charges if the Agency  cannot  produce an adequate
amount to supply the 20,500 acre feet in the year.  Three other parties are also
obligated  to  purchase  a total of  32,500  acre feet per year  under  separate
agreements with the Agency. These other participating  entities are North of the
River Municipal Water District,  East Niles Community Services District, and the
City of Bakersfield.  Further, the Agency has the right to proportionally reduce
the water  supply  provided  to all of the  participants  if it  cannot  produce
adequate  supplies.  The  participation  of all parties in the  transaction  for
expansion of the Agency's  facilities,  including the Water Purification  Plant,
purchase of the water and payment of interest  and  principal on the bonds being
issued by the Agency to finance the  transaction  is required as a condition  to
the  obligation  of the  Agency  to  proceed  with  expansion  of  the  Agency's
facilities. If any of the other parties does not use its allocation,  that party
is obligated to pay its contracted  amount,  but may make  arrangements  for the
other parties to purchase some or all of its allocation.

The Agency intends to expand its capacity to produce and transmit treated water,
either  through  expansion of its existing  water  treatment  plant  capacity or
building a new water  treatment  plant.  Also,  it will be expanding its related
transmission  systems. The Agency is planning to issue bonds to fund the project
and will use the payments of the Capital  Facilities Charges by California Water
Service  Company  and  the  other  contracted   parties  to  meet  the  Agency's
obligations  to pay  interest and repay  principal  on the bonds.  If any of the
parties  were to default on making  payments of the Capital  Facilities  Charge,
then the other parties are obligated to pay for the defaulting  party's share on
a pro-rata  basis.  If there is a payment  default by a party and the  remaining
parties have to make payments, they also are entitled to a pro-rata share of the
defaulting party's water allocation.

The Company expects to use all its contracted  amount of water in its operations
every year. In addition,  if the Company were to pay for and receive  additional
amounts of water due to a default of another  participating  party,  the Company
believes it could use this additional water in its operations  without incurring
substantial   incremental  cost  increases.   If  additional  treated  water  is
available, all parties have an option to purchase this additional treated water,
subject to the Agency's right to allocate the water among the parties.

Once the  project  is  complete,  the  Company  is  obligated  to pay a  Capital
Facilities  Charge and a Treated  Water Charge that  together  total  $4,739,000
annually, which equates to $231 per acre foot. Annual payments of $1,951,000 for
the Capital  Facilities  Charge will begin when the Agency  issues bonds to fund
the project. Some of the Treated Water Charge of $2,788,000 is expected to begin
July 1, 2007 when a portion of the planned capacity is expected to be available.
The expanded water treatment plant is expected to be at full capacity by July 1,
2008, and at that time, the full annual payments of $4,739,000 would be made and
continue  through  the  term of the  agreement.  Once  treated  water  is  being
delivered,  the Company will also be obligated  for its portion of the operating
costs;  that portion is currently  estimated to be $69 per acre foot. The actual
amount will vary due to variations from estimate, inflation and other changes in
the cost structure.  The Company's  overall estimated cost of $300 per acre foot
is less than the estimated cost of procuring  untreated  water  (assuming  water
rights could be obtained) and then providing treatment.


Item 1.02 Termination of a Material Definitive Agreement

The registrant  incorporates by reference the  information  submitted under Item
1.01 above with  respect to entry into the  agreement  with Kern  Country  Water
Agency and termination of the prior agreement.

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

The registrant  incorporates by reference the  information  submitted under Item
1.01 above with  respect to entry into the  agreement  with Kern  Country  Water
Agency.  The initial  assessment is that  components  of the  agreement  will be
accounted  for under FASB  Interpretation  No. 45,  Guarantor's  Accounting  and
Disclosure  Requirements  for  Guarantees,   Including  Indirect  Guarantees  of
Indebtedness of Others.

Item 9.01 Financial Statements and Exhibits.

The exhibit list is incorporated by reference to the Exhibit Index included with
this report.
 



                                   SIGNATURES

         Pursuant to the requirement 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.


                         CALIFORNIA WATER SERVICE GROUP
                         ------------------------------
                                  (Registrant)



Date: September 22, 2005               By:  /s/ Calvin L. Breed
                                          --------------------------------------
                                            Calvin L. Breed
                                            Controller, Assistant Secretary and
                                            Assistant Treasurer





                                  EXHIBIT INDEX

     Exhibit
      Number                       Description of Exhibits
      ------                       -----------------------

     10.1             Agreement   between  Kern  County  Water  Agency  and  the
                      California Water Service Company dated September 21, 2005