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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 pa5XHA3a6X+H1kazGjTJsQ==

<SEC-DOCUMENT>0001214912-10-000013.txt : 20100126
<SEC-HEADER>0001214912-10-000013.hdr.sgml : 20100126
<ACCEPTANCE-DATETIME>20100126180130
ACCESSION NUMBER:		0001214912-10-000013
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091231
FILED AS OF DATE:		20100126
DATE AS OF CHANGE:		20100126

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:		213 929 1800

	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:			QUINN MICHAEL O
		CENTRAL INDEX KEY:			0001063563
		STANDARD INDUSTRIAL CLASSIFICATION:	WATER SUPPLY [4941]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-08176
		FILM NUMBER:		10548646

	MAIL ADDRESS:	
		STREET 1:		SOUTHWEST WATER CO.
		STREET 2:		624 SO. GRAND AVE, STE 2900
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90017
</SEC-HEADER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2009-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001063563</rptOwnerCik>
            <rptOwnerName>QUINN MICHAEL O</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>624 SOUTH GRAND AVENUE, SUITE 2900</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President, SWS</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>153</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.5585</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>40003</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares acquired under the SWWC Employee Stock Purchase Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Barbara Libutti, Attorney in Fact  For: Michael O Quinn</signatureName>
        <signatureDate>2010-01-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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