<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-07-15</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000868271</issuerCik>
        <issuerName>SEVERN BANCORP INC</issuerName>
        <issuerTradingSymbol>SVBI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001224589</rptOwnerCik>
            <rptOwnerName>KIRKLEY S SCOTT</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-07-15</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>P</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>400</value>
            </transactionShares>
            <transactionValue>
                <value>24</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>139819</value>
                <footnoteId id="F1"/>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <footnotes>
        <footnote id="F1">Mr. Kirkley claims indirect ownership of 30,237 shares of Common Stock through the Severn Savings Bank, FSB Employee Stock Ownership Plan (ESOP).  The ESOP has 376,593 shares outstanding of which 30,237 had been allocated to Mr. Kirkley as of 12/31/02.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Scott Kirkley</signatureName>
        <signatureDate>2003-07-15</signatureDate>
    </ownerSignature>

</ownershipDocument>

