As filed with the Securities and Exchange Commission on August 11, 2005

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                              ---------------------

                                    FORM S-8


                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933


                         CALIFORNIA WATER SERVICE GROUP
                         ------------------------------
             (Exact name of registrant as specified in its charter)


                                    Delaware
                                    --------
         (State or other jurisdiction of incorporation or organization)


                                   77-0448994
                                   ----------
                     (I.R.S. Employer Identification Number)


     1720 North First Street, San Jose, California                 95112-4598
     ---------------------------------------------                 ----------
     (Address of principal executive offices)                      (Zip Code)


              California Water Service Group Equity Incentive Plan
              ----------------------------------------------------
                            (Full Title of the Plan)


                                 Richard D. Nye
                         California Water Service Group
                             1720 North First Street
                             San Jose, CA 95112-4598
                             -----------------------
                     (Name and address of agent for service)

                                 (408) 367-8200
                                 --------------
           Telephone Number, Including Area Code, of Agent For Service

<PAGE>
<TABLE>
                         CALCULATION OF REGISTRATION FEE
<CAPTION>
----------------------- ------------------ ------------------------- ------------------------ ------------------
                        Amount                                       Proposed Maximum
Title Of Securities     To Be              Proposed Maximum          Aggregate Offering       Amount Of
 To Be Registered       Registered         Offering Price Per Share  Price                    Registration Fee
----------------------- ------------------ ------------------------- ------------------------ ------------------
<S>                      <C>                    <C>                       <C>                     <C>
Common Stock, par
value $0.01 per          1,000,000 shares       $37.277                 37,277,000               $4,387.50 1/
share, along with
preferred stock
purchase rights
----------------------- ------------------ ------------------------- ------------------------ ------------------
<FN>
1/ In addition to the common stock and preferred stock purchase rights set forth
in the table, the amount to be registered  includes an  indeterminate  number of
shares issuable  pursuant to stock splits and stock dividends in accordance with
Rule 416(b). Fee calculated  pursuant to Rule 457(c) based on the average of the
high and low prices on the New York Stock Exchange on August 9, 2005 of $37.277.
</FN>
</TABLE>
<TABLE>


                                       2
<PAGE>

                                     Part I

     Note: The  document(s)  containing the  information  specified by Part I of
Form S-8 will be sent or given to employees as specified by Rule 428(b)(1).

                                     Part II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.

     The  registrant  hereby  incorporates  by  reference  in this  registration
statement the following documents:

         1) Annual  Report on Form 10-K of the  registrant  for the fiscal  year
ended December 31, 2004;

         2)  Quarterly  Report on Form 10-Q of the  registrant  for the quarters
ended March 31 and June 30, 2005;

         3) Current  Reports on Form 8-K of the registrant  filed on February 8,
April 7 and April 28, 2005 (a second  Current  Report on Form 8-K was furnished,
but not filed,  on April 28,  2005 and is not being  incorporated  by  reference
herein)  and the  Current  Report  on  Form  8-K  filed  on July  28,  2005  (as
subsequently amended);

         4) The  description of the  registrant's  common stock set forth in the
Registration Statement on Form 8-A under Section 12(b) of the Exchange Act filed
March 18,  1994 and any  future  amendment  or report  filed for the  purpose of
updating such description; and

         5) The description of the registrant's  preferred stock purchase rights
in the  Registration  Statement on Form 8-A under  Section 12(b) of the Exchange
Act filed  February  13, 1998 and any future  amendment  or report filed for the
purpose of updating such description.

         All documents filed (but not furnished) by the registrant with the
Commission after the date of this Registration Statement under Sections 13(a),
13(c), 14 and 15(d) of the Exchange Act, and before the registrant files a
post-effective amendment which reports that all securities offered in this
Registration Statement have been sold, or to deregister all unsold securities,
shall also be deemed to be incorporated by reference and to be part of this
Registration Statement from the dates we file each of those documents.


Item 4.  Description of Securities.

     The class of securities to be offered is registered under Section 12 of the
Exchange Act.

Item 5.  Interests of Named Experts and Counsel.

     Not applicable.


                                       3
<PAGE>

Item 6.  Indemnification of Officers and Directors.

     The company 's Certificate of Incorporation  provides that the liability of
our  directors,  both  to the  company  and to its  stockholders,  for  monetary
damages,  including  liability for breach of fiduciary duty, shall be eliminated
to the fullest  extent  permissible  under  Delaware law. The  Certificate  also
provides that the company shall indemnify any person who is or was a party or is
threatened to be made a party to any  proceeding by reason of the fact that that
person is or was an agent of the  company,  to the fullest  extent  permitted by
Section 145 of the Delaware General  Corporation Law. The company also maintains
officers and director's liability insurance.


Item 7.  Exemption from Registration Claimed.

     Not applicable.

Item 8.  Exhibits.

     The Exhibit Index attached hereto is incorporated by reference.

Item 9.  Undertakings.

     (a) The undersigned registrant hereby undertakes:

         (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

               (i) To include any prospectus required by Section 10(a)(3) of the
Securities Act of 1933;

               (ii) To reflect  in the  prospectus  any facts or events  arising
after the  effective  date of the  registration  statement  (or the most  recent
post-effective  amendment  thereof)  which,  individually  or in the  aggregate,
represent a fundamental  change in the information set forth in the registration
statement;

               (iii) To include any  material  information  with  respect to the
plan of distribution not previously  disclosed in the registration  statement or
any material change to such information in the registration statement;

         Provided,  however,  that  paragraphs  (a)(1)(i) and  (a)(1)(ii) do not
apply if the information  required to be included in a post-effective  amendment
by those  paragraphs is contained in periodic reports filed with or furnished to
the Commission by the registrant  pursuant to Section 13 or Section 15(d) of the
Exchange Act that are incorporated by reference in the registration statement.

         (2) That,  for the  purpose  of  determining  any  liability  under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the


                                       4
<PAGE>

offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (3) To remove from registration by means of a post-effective  amendment
any of the securities being registered which remain unsold at the termination of
the offering.

     (b) The  undersigned  registrant  hereby  undertakes  that, for purposes of
determining  any liability  under the Securities Act of 1933, each filing of the
registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Exchange Act (and, where  applicable,  each filing of an employee benefit plan's
annual  report   pursuant  to  Section  15(d)  of  the  Exchange  Act)  that  is
incorporated by reference in the registration  statement shall be deemed to be a
new registration  statement relating to the securities offered therein,  and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors,  officers and controlling  persons of
the  registrant  pursuant  to  the  foregoing  provisions,   or  otherwise,  the
registrant  has been advised that in the opinion of the  Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore,  unenforceable. In the event that a claim for indemnification
against such  liabilities  (other than the payment by the registrant of expenses
incurred or paid by a director,  officer or controlling person of the registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director,  officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been  settled by  controlling  precedent,  submit to a court of  appropriate
jurisdiction the question whether such  indemnification  by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.


                                       5
<PAGE>


                                   Signatures

The Registrant.

     Pursuant to the requirements of the Securities Act of 1933, as amended, the
registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this registration
statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized, in the City of San Jose, State of California, on August 11, 2005.

                             CALIFORNIA WATER SERVICE GROUP



                             By: /s/ Richard D. Nye
                                ----------------------
                                Richard D. Nye
                                Vice President, Chief Financial Officer
                                and Treasurer


                                       6
<PAGE>

                                POWER OF ATTORNEY

     The  officers  and  directors  of  California  Water  Service  Group  whose
signatures  appear  below  hereby  constitute  and  appoint  Peter C. Nelson and
Richard D. Nye, and each of them,  their true and lawful  attorneys  and agents,
with full  power of  substitution,  each with  power to act  alone,  to sign and
execute on behalf of the  undersigned  any  amendment or  amendments  (including
post-effective  amendments)  to this  Registration  Statement on Form S-8 and to
file the same,  with all exhibits  thereto,  and other  documents in  connection
therewith,  with the Securities and Exchange  Commission,  granting unto each of
said  attorneys-in-fact  and agents full power and  authority  to do  everything
necessary to accomplish the  foregoing,  as fully to all intents and purposes as
he or she might or could do in person,  and each of the undersigned  does hereby
ratify  and  confirm  all  that  each of said  attorneys  and  agents,  or their
substitutes, shall do or cause to be done by virtue hereof.

     Pursuant to the  requirements  of the  Securities  Act of 1933, as amended,
this  Registration  Statement  has been signed by the  following  persons in the
capacities and on the dates indicated.


     Signature                             Title
     ---------                             -----

<S>                                    <C>                                   <C>
/s/Peter C. Nelson                     President and Chief Executive         May 20, 2005
------------------                     Officer (Principal Executive
Peter C. Nelson                        Officer) and Director


/s/Richard D. Nye                      Vice President, Chief Financial       May 20, 2005
-----------------                      Officer and Treasurer (Principal
Richard D. Nye                         Financial and Accounting Officer)


/s/Robert W. Foy
----------------                       Director, Chairman of the Board       May 20, 2005
Robert W. Foy                          of Directors


/s/Douglas M. Brown                    Director                              May 20, 2005
-------------------
Douglas M. Brown


/s/Edward D. Harris, Jr., M.D.         Director                              May 20, 2005
------------------------------
Edward D. Harris, Jr., M.D.


/s/Bonnie G. Hill                      Director                              May 20, 2005
-----------------
Bonnie G. Hill


/s/David N. Kennedy                    Director                              May 20, 2005
-------------------
David N. Kennedy
</TABLE>


                                       7
<PAGE>
<TABLE>
<CAPTION>

     Signature                             Title
     ---------                             -----

<S>                                    <C>                                   <C>

/s/Richard P. Magnuson                 Director                              May 20, 2005
----------------------
Richard P. Magnuson


/s/Linda R. Meier                      Director                              May 20, 2005
-----------------
Linda R. Meier


/s/George A. Vera                      Director                              May 20, 2005
-----------------
George A. Vera
</TABLE>


                                       8
<PAGE>


                                  EXHIBIT LIST
                                  ------------


4.1      Certificate  of   Incorporation   of  California  Water  Service  Group
         (incorporated  by  reference  to  Exhibit A of the  registrant's  Proxy
         Statement dated March 18, 1999*)

4.2      Restated  By-laws  of  California  Water  Service  Group as  amended on
         January  26,  2000  (incorporated  by  reference  to Exhibit 3-2 to the
         registrant's Current Report on Form 8-K dated January 26, 2000*)

4.3      California Water Service Group Equity  Incentive Plan  (incorporated by
         reference to Appendix B of the registrant's Proxy Statement dated March
         25, 2005*)

5        Opinion of counsel as to the legality of securities being registered

23.1     Consent of counsel (included in Exhibit 5)

23.2     Consent of KPMG LLP as independent registered public accounting firm

24       Power of attorney  (included  in  signature  page of this  registration
         statement)

---------------------
*        File No. 001-13883.


                                       9
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{"company-data": {"conformed-name": "CALIFORNIA WATER SERVICE GROUP", "cik": "0001035201", "assigned-sic": "4941", "irs-number": "770448994", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-127495", "film-number": "051021122"}, "business-address": {"street1": "1720 N FIRST ST", "street2": "C/O CALIFORNIA WATER SERVICE CO", "city": "SAN JOSE", "state": "CA", "zip": "95112", "phone": "4083678200"}, "mail-address": {"street1": "1720 FIRST ST", "street2": "C/O CALIFORNIA WATER SERVICE CO", "city": "SAN JOSE", "state": "CA", "zip": "95112"}}
As filed with the Securities and Exchange Commission on August 11, 2005

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                              ---------------------

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                         CALIFORNIA WATER SERVICE GROUP
                         ------------------------------
             (Exact name of registrant as specified in its charter)

                                    Delaware
                                    --------
         (State or other jurisdiction of incorporation or organization)

                                   77-0448994
                                   ----------
                     (I.R.S. Employer Identification Number)

     1720 North First Street, San Jose, California                 95112-4598
     ---------------------------------------------                 ----------
     (Address of principal executive offices)                      (Zip Code)

              California Water Service Group Equity Incentive Plan
              ----------------------------------------------------
                            (Full Title of the Plan)

                                 Richard D. Nye
                         California Water Service Group
                             1720 North First Street
                             San Jose, CA 95112-4598
                             -----------------------
                     (Name and address of agent for service)

                                 (408) 367-8200
                                 --------------
           Telephone Number, Including Area Code, of Agent For Service
CALCULATION OF REGISTRATION FEE
----------------------- ------------------ ------------------------- ------------------------ ------------------
                        Amount                                       Proposed Maximum
Title Of Securities     To Be              Proposed Maximum          Aggregate Offering       Amount Of
 To Be Registered       Registered         Offering Price Per Share  Price                    Registration Fee
----------------------- ------------------ ------------------------- ------------------------ ------------------
Common Stock, par
value $0.01 per          1,000,000 shares       $37.277                 37,277,000               $4,387.50 1/
share, along with
preferred stock
purchase rights
----------------------- ------------------ ------------------------- ------------------------ ------------------
1/ In addition to the common stock and preferred stock purchase rights set forth
in the table, the amount to be registered  includes an  indeterminate  number of
shares issuable  pursuant to stock splits and stock dividends in accordance with
Rule 416(b). Fee calculated  pursuant to Rule 457(c) based on the average of the
high and low prices on the New York Stock Exchange on August 9, 2005 of $37.277.
2
Part I

     Note: The  document(s)  containing the  information  specified by Part I of
Form S-8 will be sent or given to employees as specified by Rule 428(b)(1).

                                     Part II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.

     The  registrant  hereby  incorporates  by  reference  in this  registration
statement the following documents:

         1) Annual  Report on Form 10-K of the  registrant  for the fiscal  year
ended December 31, 2004;

         2)  Quarterly  Report on Form 10-Q of the  registrant  for the quarters
ended March 31 and June 30, 2005;

         3) Current  Reports on Form 8-K of the registrant  filed on February 8,
April 7 and April 28, 2005 (a second  Current  Report on Form 8-K was furnished,
but not filed,  on April 28,  2005 and is not being  incorporated  by  reference
herein)  and the  Current  Report  on  Form  8-K  filed  on July  28,  2005  (as
subsequently amended);

         4) The  description of the  registrant's  common stock set forth in the
Registration Statement on Form 8-A under Section 12(b) of the Exchange Act filed
March 18,  1994 and any  future  amendment  or report  filed for the  purpose of
updating such description; and

         5) The description of the registrant's  preferred stock purchase rights
in the  Registration  Statement on Form 8-A under  Section 12(b) of the Exchange
Act filed  February  13, 1998 and any future  amendment  or report filed for the
purpose of updating such description.

         All documents filed (but not furnished) by the registrant with the
Commission after the date of this Registration Statement under Sections 13(a),
13(c), 14 and 15(d) of the Exchange Act, and before the registrant files a
post-effective amendment which reports that all securities offered in this
Registration Statement have been sold, or to deregister all unsold securities,
shall also be deemed to be incorporated by reference and to be part of this
Registration Statement from the dates we file each of those documents.

Item 4.  Description of Securities.

     The class of securities to be offered is registered under Section 12 of the
Exchange Act.

Item 5.  Interests of Named Experts and Counsel.

     Not applicable.

                                       3
Item 6.  Indemnification of Officers and Directors.

     The company 's Certificate of Incorporation  provides that the liability of
our  directors,  both  to the  company  and to its  stockholders,  for  monetary
damages,  including  liability for breach of fiduciary duty, shall be eliminated
to the fullest  extent  permissible  under  Delaware law. The  Certificate  also
provides that the company shall indemnify any person who is or was a party or is
threatened to be made a party to any  proceeding by reason of the fact that that
person is or was an agent of the  company,  to the fullest  extent  permitted by
Section 145 of the Delaware General  Corporation Law. The company also maintains
officers and director's liability insurance.

Item 7.  Exemption from Registration Claimed.

     Not applicable.

Item 8.  Exhibits.

     The Exhibit Index attached hereto is incorporated by reference.

Item 9.  Undertakings.

     (a) The undersigned registrant hereby undertakes:

         (1) To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

               (i) To include any prospectus required by Section 10(a)(3) of the
Securities Act of 1933;

               (ii) To reflect  in the  prospectus  any facts or events  arising
after the  effective  date of the  registration  statement  (or the most  recent
post-effective  amendment  thereof)  which,  individually  or in the  aggregate,
represent a fundamental  change in the information set forth in the registration
statement;

               (iii) To include any  material  information  with  respect to the
plan of distribution not previously  disclosed in the registration  statement or
any material change to such information in the registration statement;

         Provided,  however,  that  paragraphs  (a)(1)(i) and  (a)(1)(ii) do not
apply if the information  required to be included in a post-effective  amendment
by those  paragraphs is contained in periodic reports filed with or furnished to
the Commission by the registrant  pursuant to Section 13 or Section 15(d) of the
Exchange Act that are incorporated by reference in the registration statement.

         (2) That,  for the  purpose  of  determining  any  liability  under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the

                                       4
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (3) To remove from registration by means of a post-effective  amendment
any of the securities being registered which remain unsold at the termination of
the offering.

     (b) The  undersigned  registrant  hereby  undertakes  that, for purposes of
determining  any liability  under the Securities Act of 1933, each filing of the
registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Exchange Act (and, where  applicable,  each filing of an employee benefit plan's
annual  report   pursuant  to  Section  15(d)  of  the  Exchange  Act)  that  is
incorporated by reference in the registration  statement shall be deemed to be a
new registration  statement relating to the securities offered therein,  and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors,  officers and controlling  persons of
the  registrant  pursuant  to  the  foregoing  provisions,   or  otherwise,  the
registrant  has been advised that in the opinion of the  Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore,  unenforceable. In the event that a claim for indemnification
against such  liabilities  (other than the payment by the registrant of expenses
incurred or paid by a director,  officer or controlling person of the registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director,  officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been  settled by  controlling  precedent,  submit to a court of  appropriate
jurisdiction the question whether such  indemnification  by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.

                                       5
Signatures

The Registrant.

     Pursuant to the requirements of the Securities Act of 1933, as amended, the
registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this registration
statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized, in the City of San Jose, State of California, on August 11, 2005.

                             CALIFORNIA WATER SERVICE GROUP

                             By: /s/ Richard D. Nye
                                ----------------------
                                Richard D. Nye
                                Vice President, Chief Financial Officer
                                and Treasurer

                                       6
POWER OF ATTORNEY

     The  officers  and  directors  of  California  Water  Service  Group  whose
signatures  appear  below  hereby  constitute  and  appoint  Peter C. Nelson and
Richard D. Nye, and each of them,  their true and lawful  attorneys  and agents,
with full  power of  substitution,  each with  power to act  alone,  to sign and
execute on behalf of the  undersigned  any  amendment or  amendments  (including
post-effective  amendments)  to this  Registration  Statement on Form S-8 and to
file the same,  with all exhibits  thereto,  and other  documents in  connection
therewith,  with the Securities and Exchange  Commission,  granting unto each of
said  attorneys-in-fact  and agents full power and  authority  to do  everything
necessary to accomplish the  foregoing,  as fully to all intents and purposes as
he or she might or could do in person,  and each of the undersigned  does hereby
ratify  and  confirm  all  that  each of said  attorneys  and  agents,  or their
substitutes, shall do or cause to be done by virtue hereof.

     Pursuant to the  requirements  of the  Securities  Act of 1933, as amended,
this  Registration  Statement  has been signed by the  following  persons in the
capacities and on the dates indicated.

     Signature                             Title
     ---------                             -----
/s/Peter C. Nelson                     President and Chief Executive         May 20, 2005
------------------                     Officer (Principal Executive
Peter C. Nelson                        Officer) and Director

/s/Richard D. Nye                      Vice President, Chief Financial       May 20, 2005
-----------------                      Officer and Treasurer (Principal
Richard D. Nye                         Financial and Accounting Officer)

/s/Robert W. Foy
----------------                       Director, Chairman of the Board       May 20, 2005
Robert W. Foy                          of Directors

/s/Douglas M. Brown                    Director                              May 20, 2005
-------------------
Douglas M. Brown

/s/Edward D. Harris, Jr., M.D.         Director                              May 20, 2005
------------------------------
Edward D. Harris, Jr., M.D.

/s/Bonnie G. Hill                      Director                              May 20, 2005
-----------------
Bonnie G. Hill

/s/David N. Kennedy                    Director                              May 20, 2005
-------------------
David N. Kennedy
7
Signature                             Title
     ---------                             -----
/s/Richard P. Magnuson                 Director                              May 20, 2005
----------------------
Richard P. Magnuson

/s/Linda R. Meier                      Director                              May 20, 2005
-----------------
Linda R. Meier

/s/George A. Vera                      Director                              May 20, 2005
-----------------
George A. Vera
8
EXHIBIT LIST
                                  ------------

4.1      Certificate  of   Incorporation   of  California  Water  Service  Group
         (incorporated  by  reference  to  Exhibit A of the  registrant's  Proxy
         Statement dated March 18, 1999*)

4.2      Restated  By-laws  of  California  Water  Service  Group as  amended on
         January  26,  2000  (incorporated  by  reference  to Exhibit 3-2 to the
         registrant's Current Report on Form 8-K dated January 26, 2000*)

4.3      California Water Service Group Equity  Incentive Plan  (incorporated by
         reference to Appendix B of the registrant's Proxy Statement dated March
         25, 2005*)

5        Opinion of counsel as to the legality of securities being registered

23.1     Consent of counsel (included in Exhibit 5)

23.2     Consent of KPMG LLP as independent registered public accounting firm

24       Power of attorney  (included  in  signature  page of this  registration
         statement)

---------------------
*        File No. 001-13883.

                                       9