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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 NWM+6KbuNIR8KzOkantf00rf/EWN6Yryeb6jzzf/PhwZhKt9eJtXqBUpO1WPSkGn
 rQG0e3qkvdR1WrK1cZg5FQ==

<SEC-DOCUMENT>0001179110-04-017455.txt : 20040901
<SEC-HEADER>0001179110-04-017455.hdr.sgml : 20040901
<ACCEPTANCE-DATETIME>20040901214407
ACCESSION NUMBER:		0001179110-04-017455
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040901
FILED AS OF DATE:		20040901
DATE AS OF CHANGE:		20040901

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SOUTHWEST WATER CO
		CENTRAL INDEX KEY:			0000092472
		STANDARD INDUSTRIAL CLASSIFICATION:	WATER SUPPLY [4941]
		IRS NUMBER:				951840947
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		225 N BARRANCA AVE
		STREET 2:		STE 200
		CITY:			WEST COVINA
		STATE:			CA
		ZIP:			91791-1605
		BUSINESS PHONE:		6269151551

	MAIL ADDRESS:	
		STREET 1:		225 N BARRANCA AVENUE
		STREET 2:		SUITE 200
		CITY:			WEST COVINA
		STATE:			CA
		ZIP:			91791-1605

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SUBURBAN WATER SYSTEMS
		DATE OF NAME CHANGE:	19751202

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GARNIER ANTON C
		CENTRAL INDEX KEY:			0000937852

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-08176
		FILM NUMBER:		041012264

	BUSINESS ADDRESS:	
		STREET 1:		225 N BARRANCA AAVE SUITE 200
		CITY:			WEST COVINA
		STATE:			CA
		ZIP:			91791
		BUSINESS PHONE:		8189151551

	MAIL ADDRESS:	
		STREET 1:		225 N BARRANCA AVE SUITE 200
		CITY:			WEST COVINA
		STATE:			CA
		ZIP:			91791
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-09-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000092472</issuerCik>
        <issuerName>SOUTHWEST WATER CO</issuerName>
        <issuerTradingSymbol>SWWC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000937852</rptOwnerCik>
            <rptOwnerName>GARNIER ANTON C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>624 SOUTH GRAND AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 2900</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-09-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1400</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>340211</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These shares are held in a joint trust for the benefit of the person's family: Anton C. Garnier TR UA 07-01-91, FBO The Anita and Anton Garnier Family Trust.</footnote>
        <footnote id="F2">The sales reported in this Form 4 were effected pursuant to Rule 10(b)(5)-1 trading plan adopted by the reporting person on May 20, 2004.</footnote>
        <footnote id="F3">340,211 shares are owned by Mr. and Mrs. Garnier as trustees of a revocale trust for their benefit.  Also included in Mr. Garnier's beneficial ownership are 22,049 common shares representing Mr. Garnier's interest in a corporation in which Mr. Garnier is a director and a stockholder.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Anton C. Garnier</signatureName>
        <signatureDate>2004-09-01</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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