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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-02-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001506401</issuerCik>
        <issuerName>InfraREIT, Inc.</issuerName>
        <issuerTradingSymbol>HIFR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000315038</rptOwnerCik>
            <rptOwnerName>TEACHERS INSURANCE &amp; ANNUITY ASSOCIATION OF AMERICA</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>730 THIRD AVENUE, 4TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class A common stock, $0.01 par value per share</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2015-02-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6280245</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6280245</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6280245</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">See explanation under the Remarks section herein.</footnote>
    </footnotes>

    <remarks>As of the effective time of the transactions contemplated by the Merger and Transaction Agreement (the &quot;Merger Agreement&quot;), by and among InfraREIT, Inc., InfraREIT Partners, LP and InfraREIT, L.L.C., pursuant to the terms of the Merger Agreement, 6,280,245 common shares of InfraREIT, L.L.C. held by the reporting person were converted into the right to receive shares of Class A common stock of InfraREIT, Inc. (&quot;Class A Common Stock&quot;) on a one-for-one basis.  Pursuant to the amended and restated charter of InfraREIT, Inc., on or around the 32nd day following the completion of InfraREIT Inc.'s initial public offering, a number of the shares of Class A Common Stock held by the reporting person may be cancelled if it is determined that Hunt-InfraREIT, L.L.C. is owed additional carry pursuant to the terms of the partnership agreement of InfraREIT Partners, LP.  Following any such cancellation, each remaining share of Class A Common Stock will convert into one share of common stock of InfraREIT, Inc.</remarks>

    <ownerSignature>
        <signatureName>/s/ Benjamin D. Nelson as Attorney-In-Fact for Teachers Insurance and Annuity Association of America</signatureName>
        <signatureDate>2015-02-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
