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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2010-04-07</periodOfReport>

    <dateOfOriginalSubmission>2010-07-15</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000764839</issuerCik>
        <issuerName>PureSafe Water Systems, Inc.</issuerName>
        <issuerTradingSymbol>PSWS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001269483</rptOwnerCik>
            <rptOwnerName>KESSLER LESLIE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>25 FAIRCHILD AVE.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 250</rptOwnerStreet2>
            <rptOwnerCity>PLAINVIEW</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11803</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrants</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>.059</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-04-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>431034</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-04-07</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-04-07</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>431034</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10041611</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Note</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>.059</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-04-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1694915</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>100000</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-04-07</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-10-07</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1694915</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11736526</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Ms. Leslie Kessler holds (a) warrants expiring 10/14/2010 to purchase 256,410 shares of common stock at an exercise price of $0.047 per share; (b) warrants expiring 11/17/2013 to purchase 250,000 shares of common stock at an exercise price of $0.048 per share; (c) warrants expiring 4/17/2014 to purchase 4,000,000 shares of common stock at an exercise price of $0.041 per shares of common stock at an exercise price of $0.041 per share; (d) options expiring 4/17/2014 to purchase 3,000,000 shares of common stock at an exercise price of $0.041 per share; (e) warrants expiring 10/21/14 to purchase 104,167 shares of common stock at an exercise price of $0.0576 per share; and (f) warrants expiring 3/8/2015 to purchase 2,000,000 shares of common stock at an exercise price of $0.052 per share; and (g) warrants expiring April 7, 2015 for the purchase of 431,034 shares of common stock at an exercise price of $0.059 per share.</footnote>
        <footnote id="F2">Ms. Kessler also holds a $100,000 principal amount promissory note of the Company, due October 7, 2010, and convertible into 1,694,915 shares of common stock.</footnote>
        <footnote id="F3">On March 8, 2010, the Board of Directors of the Company cancelled the common stock purchase warrants issued to Ms. Leslie Kessler on March 29, 2007, and expiring March 29, 2010, for the purchase of 2,000,000 shares of common stock at an exercise price of $0.11 per share and issued to Ms. Kessler warrants expiring March 8, 2015 for the purchase of 2,000,000 shares of common stock at an exercise price of $0.052 per share.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Leslie Kessler</signatureName>
        <signatureDate>2010-12-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
