-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 SlyXNo83MaWf//ul0TlmwZKNfQYqgY+pu3DhSirb0qo36JSMIUXNTasHv93U2kdq
 nG3+Lw//Q4lW+1R1eIaDbQ==

<SEC-DOCUMENT>0001179110-05-016600.txt : 20050817
<SEC-HEADER>0001179110-05-016600.hdr.sgml : 20050817
<ACCEPTANCE-DATETIME>20050817172315
ACCESSION NUMBER:		0001179110-05-016600
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050816
FILED AS OF DATE:		20050817
DATE AS OF CHANGE:		20050817

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:		ONE WILSHIRE BUILDING
		STREET 2:		624 SOUTH GRAND AVENUE, SUITE 2900
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90017-3782
		BUSINESS PHONE:		2139291800

	MAIL ADDRESS:	
		STREET 1:		ONE WILSHIRE BUILDING
		STREET 2:		624 SOUTH GRAND AVENUE, SUITE 2900
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90017-3782

	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:		051034138

	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>2005-08-16</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>2005-08-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.43</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>366895</value>
                    <footnoteId id="F1"/>
                </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 persons family: Anton C. Garnier and Anita Garnier TR UA 07-01-91 FBO The Anita and Anton Garnier Family Trust.</footnote>
        <footnote id="F2">Gift to Pasadena Community Foundation.  The reporting person disclaims beneficial ownership of the shares held by Pasadena Community Foundation and this report should not be deemed an admission that the reporting person is the beneficial owner of these shares for purposes of Section 16 or for any other purposes.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Anton C. Garnier</signatureName>
        <signatureDate>2005-08-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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