<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-09-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001196298</issuerCik>
        <issuerName>NEPHROS INC</issuerName>
        <issuerTradingSymbol>NEPH</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001048462</rptOwnerCik>
            <rptOwnerName>WEXFORD CAPITAL LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>777 SOUTH FLAGLER DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 602 EAST</rptOwnerStreet2>
            <rptOwnerCity>WEST PALM BEACH</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33401-6122</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001472112</rptOwnerCik>
            <rptOwnerName>Wexford GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O WEXFORD CAPITAL LP</rptOwnerStreet1>
            <rptOwnerStreet2>777 SOUTH FLAGLER DRIVE, SUITE 602 EAST</rptOwnerStreet2>
            <rptOwnerCity>WEST PALM BEACH</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001001391</rptOwnerCik>
            <rptOwnerName>DAVIDSON CHARLES E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O WEXFORD CAPITAL LP</rptOwnerStreet1>
            <rptOwnerStreet2>777 SOUTH FLAGLER DRIVE, SUITE 602</rptOwnerStreet2>
            <rptOwnerCity>WEST PALM BEACH</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001048485</rptOwnerCik>
            <rptOwnerName>JACOBS JOSEPH</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O WEXFORD CAPITAL LP</rptOwnerStreet1>
            <rptOwnerStreet2>777 SOUTH FLAGLER DRIVE, SUITE 602 EAST</rptOwnerStreet2>
            <rptOwnerCity>WEST PALM BEACH</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-09-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3355111</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>189377</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-09-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>22710</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>166667</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents an in-kind distribution of certain shares of common stock from Wexford Partners 11, L.P. (&quot;WP11&quot;), Wexford 11 Advisors LLC (&quot;WP Advisors&quot;) and WPIC 2 LLC (&quot;WPIC2&quot;, and together with WP11 and WP Advisors, the &quot;Distributing Entities&quot;) that does not involve (i) a purchase or a sale of securities or (ii) any additional consideration.</footnote>
        <footnote id="F2">Represents the common stock of the Issuer held by the Distributing Entities and Wexford Spectrum Trading Limited (&quot;WST&quot;).</footnote>
        <footnote id="F3">Represents a sale of certain shares of common stock from the Distributing Entities to an entity controlled by Arthur Amron, a current director of the Issuer and a former employee of Wexford Capital LP (&quot;Wexford Capital&quot;), the proceeds of which were distributed to certain underlying investors of the Distributing Entities. No Distributing Entities shall receive any compensation, directly or indirectly, in connection with the transaction described herein.</footnote>
        <footnote id="F4">Represents the common stock of the Issuer held by WST.</footnote>
        <footnote id="F5">Wexford Capital may, by reason of its status as (i) sub-advisor of WST, (ii) investment manager of WP11 and (iii) manager of WPIC2, (WPIC2, together with WST and WP11, the &quot;Wexford Entities&quot;), be deemed to own beneficially the shares of Common Stock held by the Wexford Entities. Wexford GP may, by reason of its status as General Partner of Wexford Capital, be deemed to own beneficially the shares of Common Stock held by the Wexford Entities. Each of Messrs. Davidson and Jacobs may, by reason of his status as a controlling person of Wexford GP and WP Advisors, be deemed to own beneficially the shares of Common Stock held by the Wexford Entities and WP Advisors.</footnote>
        <footnote id="F6">Each of Wexford Capital, Wexford GP, Davidson and Jacobs shares the power to vote and to dispose of the shares of Common Stock held by the Wexford Entities. Each of Davidson and Jacobs shares the power to vote and to dispose of the shares of Common Stock held by WP Advisors. Each of Wexford Capital, Wexford GP and Messrs. Davidson and Jacobs disclaims beneficial ownership of the shares of Common Stock held by the Wexford Entities and/or WP Advisors, as applicable, and this report shall not be deemed as an admission that they are the beneficial owner of such securities except, in the case of Davidson and Jacobs, to the extent of their respective pecuniary interests therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Wexford Capital LP, By: Wexford GP LLC, its general partner, By: Mark E. Ahern, Vice President and Assistant Secretary</signatureName>
        <signatureDate>2026-09-16</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Wexford GP LLC, By: Mark E. Ahern, Vice President and Assistant Secretary</signatureName>
        <signatureDate>2026-09-16</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Charles E. Davidson</signatureName>
        <signatureDate>2026-09-16</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Joseph M. Jacobs</signatureName>
        <signatureDate>2026-09-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
