<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-06-30</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001041580</issuerCik>
        <issuerName>AMERICAN WATER STAR  INC</issuerName>
        <issuerTradingSymbol>amws</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001174049</rptOwnerCik>
            <rptOwnerName>MOHLMAN ROGER</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO, President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock, $.0001 par value</value>
        </securityTitle>
        <transactionDate>
            <value>2003-06-30</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>J</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>2867286</value>
                <footnoteId id="F1"/>
            </transactionShares>
            <transactionValue>
                <value>0.08</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>15615799</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock, $.0001 par value</value>
        </securityTitle>
        <transactionDate>
            <value>2003-06-30</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>J</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>587500</value>
                <footnoteId id="F2"/>
            </transactionShares>
            <transactionValue>
                <value>0.08</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>16203299</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>Owned by a corporation controlled by spouse</value>
            </natureOfOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <footnotes>
        <footnote id="F1">One June 30, 2003, Mr. Mohlman elected to convert the aggregate principal amount of $229,382.88 due under four promissory notes issued by the Company to Mr. Mohlman into shares of the Company's restricted Common Stock at the conversion rate of $0.08 per share.  Mr. Mohlman waived all interest due under the notes.  Upon issue of the 2,867,286 shares, the notes were cancelled on the books and records of the Company.</footnote>
        <footnote id="F2">One June 30, 2003, Camelot, Ltd. elected to convert the  principal amount of $47,000 due under a promissory note issued by the Company to Camelot, Ltd. into shares of the Company's restricted Common Stock at the conversion rate of $0.08 per share.  Camelot, Ltd. agreed to waive all interest due under the note.  Upon issue of the 587,500 shares, the note was cancelled on the books and records of the Company.  The sole officer and director of Camelot is the spouse of Mr. Mohlman.  Therefore, Mr. Mohlman is deemed to beneficially own the shares owned by Camelot, Ltd.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Roger Mohlman</signatureName>
        <signatureDate>2003-07-02</signatureDate>
    </ownerSignature>

</ownershipDocument>

