<SEC-DOCUMENT>0001127602-25-009134.txt : 20250311
<SEC-HEADER>0001127602-25-009134.hdr.sgml : 20250311
<ACCEPTANCE-DATETIME>20250311192136
ACCESSION NUMBER:		0001127602-25-009134
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250307
FILED AS OF DATE:		20250311
DATE AS OF CHANGE:		20250311

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Jenkins Kenneth G
		CENTRAL INDEX KEY:			0001996303
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13883
		FILM NUMBER:		25729520

	MAIL ADDRESS:	
		STREET 1:		1720 NORTH FIRST STREET
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95112

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CALIFORNIA WATER SERVICE GROUP
		CENTRAL INDEX KEY:			0001035201
		STANDARD INDUSTRIAL CLASSIFICATION:	WATER SUPPLY [4941]
		ORGANIZATION NAME:           	01 Energy & Transportation
		IRS NUMBER:				770448994
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1720 N FIRST ST
		STREET 2:		C/O CALIFORNIA WATER SERVICE CO
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95112
		BUSINESS PHONE:		4083678200

	MAIL ADDRESS:	
		STREET 1:		1720 FIRST ST
		STREET 2:		C/O CALIFORNIA WATER SERVICE CO
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95112
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-03-07</periodOfReport>

    <issuer>
        <issuerCik>0001035201</issuerCik>
        <issuerName>CALIFORNIA WATER SERVICE GROUP</issuerName>
        <issuerTradingSymbol>CWT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001996303</rptOwnerCik>
            <rptOwnerName>Jenkins Kenneth G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1720 NORTH FIRST STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN JOSE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95112</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>VP, Water Res. Plan &amp; Sustain</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>CommonStock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-03-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>33</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>47.90</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3955</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents the number of shares withheld by and surrendered to the issuer to satisfy the tax withholding obligations that arose in connection with the Restricted Stock (RSA)  Award 694</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Michelle R. Mortensen on behalf of Kenneth Jenkins</signatureName>
        <signatureDate>2025-03-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
