<PAGE>

                         SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, D. C. 20549

                                     FORM 10-K

                   ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 (d)
                       OF THE SECURITIES EXCHANGE ACT OF 1934


For Fiscal Year Ended   December 31, 1997  Commission file number   0-18677
                       -------------------                        -----------


                          DOMINGUEZ SERVICES CORPORATION
               ------------------------------------------------------
               (Exact name of registrant as specified in its charter)


          California                                        33-0391161
------------------------------------------------------------------------------
(State of other jurisdiction of                         (I.R.S. Employer
 incorporation or organization)                        identification no.)


     21718 South Alameda Street, Long Beach, California               90810
------------------------------------------------------------------------------
          (Address of principal executive offices)                 (Zip Code)


Registrant's telephone number, including area code       (310)834-2625
                                                   ---------------------------

Securities registered pursuant to Section 12(b) of the Act:

                                              Name of each exchange
          Title of each Class                  on which registered
          -------------------                -----------------------
                None                         The Nasdaq Stock Market

Securities registered pursuant to Section 12(g) of the Act:

                     Common Shares, $1 Par Value
                  ---------------------------------
                           (Title of Class)

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.

     Yes    X     No
          -----       -----

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K.

State the aggregate market value of the voting stock held by non-affiliates of
the registrant:

     Common Shares average bid price of $19.00 on March 18, 1998.

                         Aggregate market value $19,158,289
                         ----------------------------------

Indicate the number of shares outstanding of each of the registrant's classes of
common stock, as of the latest practicable date:

                         March 18, 1998 - 1,506,512 shares
                         ---------------------------------

Documents incorporated by reference:
     (1)  Annual report to shareholders for the year ended December 31, 1997, as
     to Part II, Items 5, 6, 7 and 8.
     (2)  Proxy statement dated April 3, 1998, as to Item 10 (part), Item 11,
     Item 12, and Item 13.
                                   (There are fourteen pages in this 10-K)

<PAGE>

                                     PART I

ITEM 1.   BUSINESS.

GENERAL

Dominguez Services Corporation ("Company") is a holding company created in
1990 through an Agreement of Merger with Dominguez Water Company.  The
Company's principal business is the ownership of all the common stock of
Dominguez Water Company.  The holding company structure provides operational
and financial flexibility and allows the Company to engage in non-utility
activities.  The Company has two wholly-owned subsidiaries: Dominguez Water
Company, which is involved in water supply and distribution, and DSC
Investments, which is involved in non-regulated, water-related services and
investments.

Dominguez Water Company and its operating subsidiaries (collectively referred
to as "Dominguez") are regulated by the California Public Utilities
Commission ("CPUC").  Dominguez produce and supply water for residential,
commercial, public authority, business and industrial customers.  Dominguez
is comprised of its principal division, the South Bay division and its
operating subsidiaries, the Kern River Valley Water Company and the Antelope
Valley Water Company (collectively referred to as the "Subsidiaries").

The South Bay division has been providing water service for more than 86
years and is Dominguez' largest service area.  The South Bay division
encompasses most of the City of Carson, one-quarter of Torrance, parts of
Compton, Long Beach, Harbor City and Los Angeles County, and serves 32,393
customer connections. Antelope Valley Water Company, with 1,235 customers,
has four distinct service areas in northern Los Angeles County.  Kern River
Valley Water Company, located in Kern County around Isabella Lake, has nine
distinct service areas and 4,008 customers.

DSC Investments primary source of income is from the transfer of water rights
between third parties. Income from the transfers of water rights may
significantly vary from year to year due to demands for groundwater by major
pumpers in the West and Central Groundwater Basins.  DSC Investments also
holds a twenty percent ownership in Chemical Services Company ("CSC") with an
option to acquire an additional forty percent interest through the year 2001.
CSC manufactures and distributes chlorine generators used in the water and
wastewater industry to produce safe on-site chlorine disinfectant.

                                                                             2

<PAGE>

OPERATIONS

In 1997, Dominguez supplied 12,362 million gallons of water to 37,636 customers,
compared to 11,481 million gallons of water to 36,882 customers in 1996.  The
South Bay division produced 11,702 million gallons of water in 1997 and 11,173
million gallons in 1996.  Although Dominguez has a diversified customer base, a
substantial portion, 49% in 1997 and 46% in 1996, of sales were derived from
business and industrial usage.  Furthermore, a single customer, a refinery,
accounted for 33% of these business and industrial sales in 1997, and for 32% in
1996.

WATER SUPPLY

The water supplies for Dominguez come from its own groundwater wells plus two
water wholesalers of imported water.

All service areas obtain either a portion of or all of their supply from
groundwater wells.  The quantity that the South Bay division is allowed to
pump over a year's time is fixed by court adjudication.  The adjudication
established distinct groundwater basins, which are managed by a
court-appointed watermaster. The groundwater management fixes the safe yield
of the basins and ensures the replenishment of the basins by utilizing
impounded storm water, treated recycled water and purchased water when
necessary.  Groundwater basins have not been adjudicated in the Subsidiaries.

The South Bay division and Leona Valley service area of Antelope Valley also
purchase water from wholesalers to supplement groundwater.  The South Bay
division purchases imported water from the Metropolitan Water District (MWD)
of Southern California.  The Leona Valley service area purchases its imported
water from Antelope Valley - East Kern Water Agency (AVEK).  Both of these
wholesale suppliers obtain water from the California State Water Project
(SWP), and MWD also obtains water from the Colorado River.

Long-term imported water supplies are dependent upon several factors.
Dominguez' future dependency on imported water will be subject to the
availability and usage of recycled water in the region as well as customer's
long-term water conservation efforts.  Dominguez has and will continue to
promote long-term water conservation efforts and will advance the use of
recycled water, when available.

In November 1997, the Company entered into an agreement with West Basin
Municipal Water District ("West Basin") and ARCO Los Angeles Refinery in
Carson ("ARCO").  Under the terms of the agreement, Dominguez will sell ARCO
recycled water purchased from West Basin for the same cost of water margin
that Dominguez would otherwise have received providing ARCO with potable
water.

                                                                           3

<PAGE>

The Company is expected to commit funds up to $2,000,000 by December 1999 to
construct recycled water facilities in its South Bay service area.  At that
time, Dominguez will offer the recycled water to its customers.  The
availability of recycled water will reduce  Dominguez'  demand for imported
water, the availability of which may be uncertain in the future.   Reduced
imported water supplies and annual population growth could create future
drought conditions in Southern California; however , Dominguez believes that
the availability of recycled water will significantly mitigate the impact of
future droughts in the Dominguez service area.

Legislative actions continue to play a role in the long-term availability of
water for Southern California.  The amount of SWP water available from
Northern California and water imported from the Colorado River may be
significantly reduced around the beginning of the next century.  Future
drought conditions may require water rationing by all water agencies,
including Dominguez.

WATER QUALITY

The Company is subject to water quality regulations promulgated by the United
States Environmental Protection Agency (EPA) and the California Department of
Health Services (DHS).  Both groundwater and purchased water are subject to
extensive analysis.  With occasional minor exceptions, the Company meets all
current primary water standards.  During 1997, the Company began using an
alternative water source to meet the needs of 239 customers in one of the
Subsidiary system in order to comply with state and federal standards for
radioactivity.

In 1997, the Company participated with many other large water companies in a
monthly water sampling data acquisition program known as the Information
Collection Rule.  Data collected will be used by the EPA to establish future
drinking water standards.  Under the Federal Safe Drinking Water Act, the EPA
is required to continue to establish new maximum levels for additional
chemicals. The costs of future compliance are unknown, but the Company could
be required to perform more quality testing and treatment.  Management
believes that the Company resources will be sufficient to meet these
anticipated requirements.

The Company is subject to other applicable environmental regulations related
to the handling, storage and disposal of hazardous materials.  The Company is
currently in compliance with all such regulations.

                                                                           4

<PAGE>

REGULATORY AFFAIRS

In 1996, Dominguez filed for and received an approval to increase revenues
effective February 1, 1997, for approximately $375,000 annually, or 1.6%, to
recover the increased cost of purchased water effective January 1, 1997.
This rate increase does not increase earnings of the Company, but rather
offsets the effects of higher water production costs to Dominguez.

In 1997, Senate Bill 1268 was signed into law, requiring the CPUC to use the
standard of fair-market value when establishing the rate base value for the
acquired distribution system assets of a public water system.  The CPUC has
initiated a proceeding to develop guidelines necessary to implement the law
and to investigate other regulatory issues unique to the water industry.  The
Company believes that the new law will benefit the Company in  its
acquisition of small water systems, and that the CPUC's proceeding will
clarify rules necessary for the Company to actively pursue public-private
partnerships.

NON-UTILITY SUBSIDIARY OPERATIONS

DSC Investments invested $350,000 in CSC on December 20, 1996 and acquired a
twenty percent equity ownership with the option to acquire an additional
forty percent through the year 2001. Under the investment agreements, the
Company is obligated to provide working cash and long-term financing for the
leasing of chlorine generators to CSC, subject to the financial condition of
CSC.  The maximum loan balances available to CSC for the following calendar
years are $2,500,000 (1998), $3,000,000 (1999), $3,500,000 (2000) and
$3,500,000 (2001). As of December 31, 1997, the Company had $400,000 in
outstanding loans to CSC.

On April 26, 1996, the Company sold the remaining assets of Hydro-Metric
Service operation to a former employee in exchange for a two year note
receivable with an outstanding balance of $15,000 as of December 31, 1997.
The sale resulted in a net gain of $39,000.

During 1997, DSC Investments facilitated transfers of water right leases
between third parties, adding $438,000 to the Company's revenue.  The future
income from the transfer of water right leases will depend upon the need to
pump groundwater by major industrial users and water purveyors.

                                                                           5

<PAGE>

EMPLOYEE RELATIONS

As of December 31, 1997, the Company had a total of 73 employees in utility
and non-utility operations.  None of the employees is represented by a labor
organization, and there has never been a work stoppage or interruption due to
a labor dispute.  In general, wages, hours, and conditions of employment are
equivalent to those found in the industry.  Dominguez considers its relations
with its employees to be excellent.  All employees receive paid annual
vacations and sick leave.  Dominguez provides and pays the cost of group
life, disability, medical and dental insurance, as well as pensions, for its
employees.

ENVIRONMENTAL MATTERS

Dominguez' operations are subject to pollution control and water quality
control as discussed in the "Water Quality" section.

Other state and local environmental regulations apply to Dominguez operations
and facilities.  These regulations are primarily related to the handling,
storage and disposal of hazardous materials.  Dominguez is currently in
compliance with all other state and local regulations.

                                                                           6

<PAGE>

ITEM 2.   PROPERTIES.

The Company's general administrative and executive offices are located at
21718 South Alameda Street in Carson, California.  The Company is in the
process to sell its Alameda Street property.  Concurrently, the Company has
retained a broker to locate a replacement facility within the Dominguez
service area.

The South Bay division has prior rights to lay distribution mains and for
other uses on much of the public and private lands in its service area.
Dominguez' claim of prior rights is derived from the original Spanish land
grant covering the Dominguez service area.  For this reason, Dominguez,
unlike most other public utilities, generally receives compensation from the
appropriate public authority when the relocation of its facilities is
necessitated by the construction of roads or other projects.  It is common
for public utilities to bear the entire cost of such relocation.

Substantially all of the property of Dominguez is subject to the lien of the
Trust Indenture dated August 1, 1954, as supplemented and amended, to Chase
Manhattan Bank and Trust Company, N.A., as Trustee, securing the two
outstanding series of Dominguez' First Mortgage Bonds.

                                                                           7

<PAGE>

ITEM 3.   LEGAL PROCEEDINGS.

The Company is routinely involved in condemnation proceedings and legal
actions. The Company does not believe these matters will have a material
adverse effect, if any, on its financial position or results of operations.
For prior year issues, reference is made to page 27 Note 15 of Notes to
Consolidated Financial Statements of the Annual Report to Shareholders.

ITEM 4.   SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

None.

                                                                           8

<PAGE>

                                      PART II


ITEM 5.   MARKET FOR THE REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER
          MATTERS.

          (a)  MARKET PRICE FOR COMMON SHARES

               The information required by this item is incorporated herein
               by reference to the page 28 "Market Information" of the Annual
               Report listed in Item 14 of Part IV of this report.

          (b)  APPROXIMATE NUMBER OF HOLDERS OF COMMON SHARES

               The Nasdaq Stock Market maintenance standards require that
               Nasdaq  National Market companies have at least 400
               shareholders of round lots. As of December 31, 1997, the
               Company  complied with the standard with 298 common
               shareholders of record and more than 659 beneficial
               shareholders, who have elected to hold their shares in street
               name.

          (c)  DIVIDENDS DECLARED

               The information required by this item is incorporated herein
               by reference to the page 28 "Market Information" of the Annual
               Report listed in Item 14 of Part IV of this report.

          (d)  DIVIDEND RESTRICTION

               The information required by this item is incorporated herein
               by reference to the page 22 Note 3 "Restriction on Dividends"
               of the Annual Report listed in Item 14 of Part IV of this
               report.

ITEM 6.   SELECTED FINANCIAL DATA.

          The information required by this item is incorporated herein by
          reference to the page 16 and page 17 "Eleven Year Statistical
          Review" of the Annual Report listed in Item 14 of Part IV of this
          report.

ITEM 7.   MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
          RESULTS OF OPERATIONS.

          The information required by this item is incorporated herein by
          reference to the page 12 to 15 "Management's Discussion and
          Analysis" of the Annual Report listed in Item 14 of Part IV of this
          report.

                                                                           9

<PAGE>

ITEM 8.   FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA.

          The information required by this item is incorporated herein by
          reference to the Annual Report listed in Item 14 of Part IV of this
          report:

          -   Page 18, Consolidated Balance Sheets - December 31, 1997 and 1996;

          -   Page 19, Consolidated Statements of Income for the years ended
              December 31, 1997, 1996 and 1995;

          -   Page 19, Consolidated Statements of Common Shareholders' Equity
              for the years ended December 31, 1997, 1996 and 1995.

          -   Page 20, Consolidated Statements of Cash Flows for the years
              ended December 31, 1997, 1996 and 1995;

          -   Page 21 to 27, Notes to Consolidated Financial Statements;

          -   Page 11, Report of Independent Public Accountants.

ITEM 9.   CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
          FINANCIAL DISCLOSURE.

          None

                                                                           10

<PAGE>

                                PART III

ITEM 10.  DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT.

The following table sets forth the names and ages of all directors and executive
officers, indicating the positions and offices presently held by each.

<TABLE>
<CAPTION>
     NAME                     AGE  POSITION AND OFFICE
     ----                     ---  -------------------
     <S>                      <C>  <C>
     Dwight C. Baum           85   Director
     Richard M. Cannon        56   Director
     Terrill M. Gloege        62   Director
     Thomas W. Huston         36   Director
     C. Bradley Olson         57   Director
     Langdon Owen             67   Director
     Charles W. Porter        67   Director
     Debra L. Reed            41   Director
     Brian J. Brady           49   Chief Executive Officer, President and
                                     Chairman of the Board
     John S. Tootle           43   Chief Financial Officer, Vice President
                                     of Finance, Treasurer and Secretary
</TABLE>

There is no "family relationship" between any of the executive officers.

Information responding to Item 10 is included in the Company's proxy statement
for the 1998 Annual Meeting of Shareholders ("Proxy") pursuant to Regulation 14A
and is incorporated by reference herein pursuant to General Instruction G(3).

ITEM 11.  EXECUTIVE COMPENSATION.

Information responding to Item 11 was included in the Proxy (page 11) pursuant
to Regulation 14A and is incorporated by reference herein pursuant to General
Instruction G(3).

ITEM 12.  SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT.

Information responding to Item 12 was included in the Proxy (page 3) pursuant to
Regulation 14A and is incorporated by reference herein pursuant to General
Instruction G(3).

                                                                           11

<PAGE>

ITEM 13.  CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS.

Information responding to Item 13 was included in the Proxy (page 13) pursuant
to Regulation 14A and is incorporated by reference herein pursuant to General
Instruction G(3).  Other information is included in Note 13 of the Notes to
Consolidated Financial Statements of the Annual Report to Shareholders.

                                                                           12

<PAGE>

                                      PART IV

ITEM 14.  EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K.

          (a)             The following exhibits are filed as part of the
                          report

               1.         LIST OF FINANCIAL STATEMENTS
                          The consolidated financial statements listed in
                          the accompanying Financial Statements and
                          Schedules are filed as part of this Report.

               2.         LIST OF FINANCIAL STATEMENT SCHEDULES
                          The financial statement schedules listed in the
                          accompanying Financial Statements and Schedules
                          are filed as part of this Report.

               3.         The exhibits listed in the accompanying Index to
                          Exhibits are filed as part of this Report.

                   10.1   Agreement with West Basin and ARCO
                   10.2   The Eleventh Supplemental Trust Indenture dated
                          December 27, 1993
                   10.3   The Twelfth Supplemental Trust Indenture 12 dated
                          December 1, 1997
                   23     Report of Independent Public Accountants

          (b)  The Company filed a Form 8-K November 19, 1997,
               announcing 3-for-2 stock split effective January 2, 1998.

                                                                           13

<PAGE>

                                     SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange
Act of 1934, the Registrant has duly caused this report to be signed on its
behalf by the undersigned thereunto duly authorized.

                                         DOMINGUEZ SERVICES CORPORATION:

                                         By
                                            ----------------------------------
                                         Brian J. Brady, Chief Executive Officer


                                         By
                                            ----------------------------------
                                         John S. Tootle, Chief Financial
                                         Officer, Treasurer, Secretary


                                         By
                                            ----------------------------------
                                         Cynthia C. Chu, Corporate Controller


Pursuant to the requirements of the Securities Exchange Act of 1934, this report
has been signed below by the following persons on behalf of the Registrant and
in the capacities and on the dates indicated.

                                         DIRECTORS:

                                         -------------------------------------
                                         B. J. Brady, Chairman         Date

                                         -------------------------------------
                                         D. C. Baum                    Date

                                         -------------------------------------
                                         R. M. Cannon                  Date

                                         -------------------------------------
                                         T. M. Gloege                  Date

                                         -------------------------------------
                                         T. W. Huston                  Date

                                         -------------------------------------
                                         C. B. Olson                   Date

                                         -------------------------------------
                                         L. W. Owen                    Date

                                         -------------------------------------
                                         C. W. Porter                  Date

                                         -------------------------------------
                                         D. L. Reed                    Date

                                                                             14

<PAGE>


                           DOMINGUEZ SERVICES CORPORATION
                                  And Subsidiaries

                  SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS

<TABLE>
<CAPTION>
        Col. A                 Col. B          Col. C         Col. D         Col. E         Col. F
        ------                 ------          ------         ------         ------         ------

                                            ADDITION
                                            --------
                                                               (1)
                                                            Charged to
                              Balance at      Charged to      Other             (2)        Balance at
                              Beginning       Costs and      Accounts -     Deductions -     End of
      Description             of Period       Expenses       Describe       Describe         Period
      -----------             ----------      ----------     --------       ----------     ----------
<S>                           <C>             <C>           <C>             <C>            <C>
Allowance for doubtful
 accounts:
  Year Ended
  December 31, 1997           $285,385        $ 60,000      $11,713         $ 56,137       $300,961
                              --------        --------      -------         --------       --------
                              --------        --------      -------         --------       --------
  Year Ended
  December 31, 1996           $250,140        $132,000      $11,712         $108,467       $285,385
                              --------        --------      -------         --------       --------
                              --------        --------      -------         --------       --------
  Year Ended
  December 31, 1995           $196,361        $120,000      $ 5,490         $ 71,711       $250,140
                              --------        --------      -------         --------       --------
                              --------        --------      -------         --------       --------
</TABLE>

Notes:

(1) Receipts on accounts previously written off.

(2) Accounts receivable write off.

                                                                             15