Being in a domestic partnership affects your taxes in one overriding way: the IRS treats you and your partner as two unmarried individuals, no matter what your state calls the relationship.1Internal Revenue Service. Answers to Frequently Asked Questions for Registered Domestic Partners and Individuals in Civil Unions That single rule drives everything else. You file separate federal returns, you lose the spousal breaks married couples take for granted, and you pick up a surprising amount of extra paperwork around shared income, employer benefits, gifts, and inherited retirement accounts.
Your Federal Filing Status
Neither “Married Filing Jointly” nor “Married Filing Separately” is available to you. Each partner files their own Form 1040, and the default status is Single.
You may qualify for Head of Household, but only if you pay more than half the cost of keeping up your home and a qualifying child or qualifying relative (someone other than your partner) lives with you for more than half the year.2Internal Revenue Service. Publication 501 (2025), Dependents, Standard Deduction, and Filing Information Your partner alone cannot be the person who makes you Head of Household, even if you claim them as a dependent.1Internal Revenue Service. Answers to Frequently Asked Questions for Registered Domestic Partners and Individuals in Civil Unions
The dollars matter. For 2026, a Single filer gets a $16,100 standard deduction; Head of Household gets $24,150.3Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill A married couple filing jointly gets a larger combined deduction and wider tax brackets. Two domestic partners with incomes similar to a married couple’s often end up paying more total federal tax.
State Returns and Community Property
Some states that recognize domestic partnerships require or allow partners to file their state return using a married status. If that applies to you, you end up single on the federal return and married on the state return. Preparers usually handle this by building a “mock” federal joint return just to generate the numbers the state form needs, then filing the real federal returns separately. Expect extra time and, if you pay someone, extra cost.
Community property states add another layer. In California, Nevada, and Washington, registered domestic partners are subject to community property rules, which generally treat income earned by either partner during the relationship as belonging equally to both. For federal purposes, each partner reports half of the combined community income on their own return. IRS Publication 555 sets out the rules, and each partner must attach Form 8958 showing how income was split.4Internal Revenue Service. Publication 555 (2024), Community Property Allocating this incorrectly is one of the more common audit triggers for registered partners in those states.
Claiming Your Partner as a Dependent
You may be able to claim your partner as a “qualifying relative.” No family relationship is required, but every one of these tests must be met in the same year:
- Your partner’s gross income is less than $5,050 for the year.
- You provide more than half of their total support.
- They live with you all year as a member of your household.
- They are a U.S. citizen, U.S. national, or resident of the U.S., Canada, or Mexico.
- They are not a qualifying child of another taxpayer.
All five must hold at once.5Internal Revenue Service. Dependents The gross income cap is what disqualifies most partners; any meaningful wages blow past it. If your partner does qualify, you can claim the Credit for Other Dependents, a nonrefundable credit worth up to $500.6Internal Revenue Service. Understanding the Credit for Other Dependents Your partner’s child may also qualify as your dependent under either the qualifying child or qualifying relative rules, and when a child lives with both of you, choosing which partner claims them can meaningfully change each return.
Employer Health Coverage Becomes Taxable
Many employers extend health insurance to domestic partners. Because the IRS does not treat your partner as a spouse, that coverage does not get the same tax-free treatment a spouse’s would.7Office of the Law Revision Counsel. 26 U.S. Code 106 – Contributions by Employer to Accident and Health Plans The fair market value of the coverage your employer provides for your partner is added to your taxable wages as “imputed income.” It shows up on your W-2 and is subject to federal income tax, Social Security, and Medicare. If covering your partner costs the employer $6,000 a year, you pay tax on $6,000 you never see. A married employee with identical coverage for a spouse pays no additional tax.
There is one exception. If your partner qualifies as your tax dependent under the qualifying relative tests, the coverage can be excluded from your income.1Internal Revenue Service. Answers to Frequently Asked Questions for Registered Domestic Partners and Individuals in Civil Unions The gross income limit makes that exception hard to use for most working partners.
Gifts and Estates
Married couples can move unlimited assets to each other during life or at death with no gift or estate tax. That unlimited marital deduction is available only to legal spouses.8Office of the Law Revision Counsel. 26 USC 2056 – Bequests, Etc., to Surviving Spouse Domestic partners do not get it.
For 2026, you can give your partner up to $19,000 without filing a gift tax return. Anything above that counts against the lifetime exemption of $15,000,000.3Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill Few people owe actual gift tax because the lifetime number is so high, but gifts above the annual exclusion still require Form 709, and every dollar you move to your partner reduces the exemption you have left.9Internal Revenue Service. What’s New – Estate and Gift Tax
Watch the hidden gifts. Adding your partner to your home’s title by quitclaim deed is a taxable gift of half the fair market value. On a $500,000 house, that is a $250,000 gift, well above the annual exclusion and requiring Form 709.
The estate side bites harder. If one partner dies and leaves assets to the other, the full value sits in the decedent’s taxable estate. A spouse would inherit the same assets tax-free. For partners whose combined assets approach the lifetime exemption, the difference can run into hundreds of thousands of dollars. If that describes you, bring in an estate planning attorney.
Retirement Accounts
If one spouse in a marriage has no earned income, the working spouse can still fund a “spousal IRA” on their behalf, up to $7,500 for 2026 or $8,600 if the account holder is 50 or older.10Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026; IRA Limit Increases to $7,500 That option requires a joint return. You cannot fund an IRA for a non-working partner. Each of you needs your own earned income to contribute.
Inheritance is where the gap really hurts. A surviving spouse who inherits an IRA or 401(k) can roll it into their own account and keep deferring. A domestic partner is a non-spouse beneficiary. Unless you qualify as an “eligible designated beneficiary” (disabled, chronically ill, or no more than 10 years younger than your partner), you must empty the inherited account within 10 years of their death.11Internal Revenue Service. Retirement Topics – Beneficiary A $500,000 traditional IRA has to come out within a decade, every dollar as ordinary income. A spouse could spread the same balance across a lifetime at far lower annual rates.
Reporting Shared Income and Deductions
Mortgage interest and property taxes work by payment, not by name on the loan. If you co-own and both contribute from a joint account, splitting 50/50 is the standard approach.12Internal Revenue Service. Other Deduction Questions 2 Only one of you will receive the Form 1098. The partner who got it claims their share on Schedule A; the other claims their share on the line for interest not reported on a 1098 and attaches a statement identifying you and the split.13Internal Revenue Service. Publication 936 (2025), Home Mortgage Interest Deduction Keep records showing who paid what.
Joint bank interest requires more work than most people realize. The bank issues one Form 1099-INT, usually in the primary holder’s name. Married spouses can just report it. You cannot. The partner who received the 1099-INT is a “nominee” for the other partner’s share and must file a separate 1099-INT with the IRS allocating that share, then send a copy to the other partner.14Internal Revenue Service. Topic No. 403, Interest Received Skip the nominee filing and the IRS will treat all the interest as belonging to the name on the form.
For charitable contributions, medical expenses, and other itemized deductions, the rule is simple: you deduct what you personally paid with your own funds. If your partner writes the check, the deduction is theirs.
Social Security Benefits
Social Security is built around legal marriage. A spouse can claim spousal benefits on the other’s work record and survivor benefits after death. Domestic partners generally cannot. The Social Security Administration has recognized limited exceptions for some same-sex couples in civil unions or domestic partnerships under specific circumstances, but those are narrow and fact-dependent. For most domestic partners, each partner’s benefits depend entirely on their own earnings history, with no ability to claim on the other’s record. Where one partner earned far more over a career, that gap can mean tens of thousands of dollars in lifetime benefits a surviving spouse would have received automatically.