IRS Domestic Partner Tax: Filing, Dependents, and Deductions

The IRS does not recognize a registered domestic partnership as a marriage, so the IRS domestic partner tax rules require each partner to file an individual federal return. Neither Married Filing Jointly nor Married Filing Separately is available to you, no matter what your state calls the relationship.¹ That single fact drives almost every other decision on your return.

Your Filing Status: Single or Head of Household

Most domestic partners file as Single. For 2026, the Single standard deduction is $16,100. If you qualify for Head of Household instead, the standard deduction rises to $24,150 and the brackets widen, which lowers your effective rate on the same income.²

Three conditions have to be met to claim Head of Household:³

You were unmarried on December 31. A domestic partnership isn’t a marriage for federal purposes, so this test is automatic.
You paid more than half the cost of keeping up the home, counting rent or mortgage, property taxes, insurance, utilities, and food eaten at home.
A qualifying person lived with you for more than half the year, usually a dependent child. Your partner only counts if they meet the full qualifying relative tests below.

If your partner doesn’t qualify but a child or other relative does, you can still claim Head of Household through that person. Keep documentation showing you paid the majority of household costs.

Claiming Your Partner as a Dependent

A domestic partner can only be claimed under the qualifying relative rules. All four tests must be met:⁴

Member of household. Your partner must live with you as a member of your household for the entire year. Short absences for travel or medical care generally don’t break the test; a long separation can.
Gross income. Your partner’s gross income must stay below the exemption amount, which was $5,200 for 2025 and adjusts each year. A partner working full time will almost certainly exceed it.³
Support. You must provide more than half of your partner’s total support for the year, including housing, food, clothing, medical care, and education. Money your partner earns but saves doesn’t count toward their own support.
Not a qualifying child. Your partner can’t already be claimed as a qualifying child by someone else.

What Dependent Status Actually Gets You

Expectations here need recalibrating. Under the One Big Beautiful Bill Act, the personal exemption deduction remains at $0, so claiming your partner as a dependent no longer cuts your taxable income directly the way it did before 2018.² What dependent status still gets you is real money through other doors: it can qualify you for Head of Household, strip the imputed income off employer health coverage, and let you deduct medical expenses you pay on your partner’s behalf. Together, those can save thousands a year.

Employer Health Coverage and Imputed Income

When your employer covers your domestic partner under its health plan, the fair market value of that coverage is usually added to your taxable wages as imputed income. It lands in Box 1 of your W-2 alongside your regular pay, and you owe federal income tax plus FICA on it. The hit shows up in every paycheck, not just at filing time.

The numbers add up fast. If your employer’s share of your partner’s premium is $230 per biweekly pay period, that’s roughly $6,000 added to your annual taxable income. A worker in the 22% bracket owes about $1,320 in extra income tax plus roughly $460 in additional FICA, purely for covering a partner. A married employee covering a spouse owes nothing extra on the same benefit.

The Dependent Exception

If your partner qualifies as your tax dependent, the imputed income disappears. Employer-provided health coverage for an employee’s dependents is excluded from gross income under federal regulations.⁵ Your employer will typically ask you to certify your partner’s dependent status before removing the imputed amount from your wages. If your partner stops qualifying mid-year, the exclusion ends and imputed income kicks back in.

A Broader Definition for Health Coverage

The dependent definition for health coverage is more generous than the general one. The regulations drop the gross income test when determining dependent status for employer health benefits.⁵ Your partner still has to live with you all year and you still have to provide more than half their support, but they can earn above the usual threshold and still qualify for the health exclusion. The same broader definition applies to medical expense deductions.

Deducting Medical Expenses You Pay for Your Partner

If your partner meets the dependent tests for medical purposes (member of household and support, without the gross income limit), you can include medical expenses you pay for them when calculating your own medical expense deduction. That covers doctor visits, prescriptions, dental work, and health insurance premiums paid out of pocket.

The usual threshold applies: only the portion of total medical expenses that exceeds 7.5% of your adjusted gross income is deductible. Keep receipts and records showing the money came from your funds. The IRS can disallow the deduction if you can’t demonstrate who paid.

Splitting Income and Shared Deductions

Because you file separately, income is taxed to whoever earned it, regardless of which bank account the paycheck lands in. If one of you earns $80,000 and the other $30,000, each reports their own figure. Investment income from a jointly held brokerage account is generally split equally unless you can document unequal ownership.

Mortgage Interest and Property Taxes

To deduct mortgage interest you must be legally liable on the debt and actually make the payment.⁶ If both of you are on the note, each deducts the share you actually paid. One paid 60% of the year’s interest and the other 40%? Each takes that portion on their own Schedule A.

When only one partner is on the mortgage, only that partner can claim the deduction, even if the other contributed cash toward the payments. The contributing partner is effectively making a gift (see below). If both of you are liable but only one received the Form 1098, the IRS tells you to attach a statement to your paper return showing how you split the interest.⁶

Property taxes work the same way. The partner legally liable who makes the payment claims the deduction. Keep bank statements showing which account each payment came from.

Community Property States: California, Nevada, and Washington

Three states treat registered domestic partners the same as married spouses for community property: California, Nevada, and Washington.⁷ If you’re registered in one of these states, federal tax law requires you to apply the state’s community property rules on your separate federal returns. Each partner reports half of the couple’s combined community income, regardless of who earned it.

Community income generally includes wages, self-employment earnings, and investment income earned while domiciled in the state. Separate property income (from assets you owned before the partnership or received by gift or inheritance) stays on the owning partner’s return.

Partners in these three states file Form 8958 with their federal returns to document the allocation of each income item and tax withholding.⁸ Each partner gets credit for half of the federal income tax withheld on community wages. The form walks through wages, interest, self-employment income, withholding, and estimated payments line by line.

Gift and Estate Tax Between Partners

Married couples get an unlimited marital deduction: one spouse can transfer any amount to the other, during life or at death, with no gift or estate tax. Domestic partners get none of that. Every transfer between you is treated the same as a transfer between unrelated people.⁹

Lifetime Gifts

You can give your partner up to $19,000 in 2026 (the annual exclusion) without filing a gift tax return. Gifts above that require filing Form 709, though no tax is actually owed until your cumulative lifetime gifts exceed the basic exclusion of $15,000,000.¹⁰

This matters more than most couples realize. If one partner pays the full mortgage on a jointly owned home, the portion tied to the other partner’s ownership share is technically a gift. Same with paying off a partner’s credit cards, student loans, or car payments. Small amounts rarely cause trouble; large, ongoing transfers chip away at your lifetime exclusion.

Transfers at Death

When a domestic partner dies, everything they leave the surviving partner counts toward the taxable estate, with no marital deduction to shelter it. The $15,000,000 basic exclusion covers most estates, but partners whose combined assets approach that level need planning. A married couple can shelter up to $30,000,000 using both spouses’ exclusions through portability; domestic partners cannot, because the portability election is only available to surviving spouses.

Some states with their own inheritance taxes charge roughly 10% to 16% on transfers to non-relatives, and a few classify domestic partners as non-relatives even when they recognize the partnership for other purposes. State exemption thresholds are far lower than the federal amount.

Retirement Accounts and Social Security

Federal retirement law is built around marriage, and domestic partners sit outside most of the automatic protections.

Spousal IRA Contributions

A married couple with one non-working spouse can still fund that spouse’s IRA using the working spouse’s income. Domestic partners cannot do this.¹¹ If your partner has no earned income, they generally can’t contribute to a traditional or Roth IRA at all.

401(k) Beneficiary Designations

A married spouse is typically the automatic beneficiary of an employer-sponsored plan like a 401(k), and the plan must get the spouse’s written consent before naming someone else. Domestic partners have no such default. If your partner never names you, or a beneficiary form gets lost during a job change, the account could pass to a default beneficiary (often a parent or the estate) instead of to you. Update beneficiary forms proactively and keep copies.

Social Security

Married spouses can claim Social Security benefits on each other’s earnings records, including survivor benefits. Domestic partners generally cannot. The SSA has recognized some non-marital same-sex relationships in narrow circumstances tied to prior unconstitutional state marriage bans; if that might describe you, contact the SSA directly.¹² Otherwise, each partner’s benefit depends solely on their own work record.

Earned Income Tax Credit

Because you file separately, EITC eligibility is determined for each partner independently. If you have a qualifying child living with you, you can claim the EITC on your own return based on your own earned income, even though your partner also lives in the home.¹³

When both partners have qualifying children, each partner can potentially claim the credit based on their own child. With two children in the home, one parent can claim EITC on one child and the other parent on the second. Both partners cannot claim the same child. If they do, the IRS tiebreaker awards the child to the parent the child lived with longer during the year, or to the parent with the higher adjusted gross income if the time was equal.¹³

One catch surprises people: EITC income limits are lower for Single and Head of Household filers than for married couples filing jointly. Two domestic partners with moderate incomes might both qualify individually, or one might be pushed over the limit by their own earnings. Run the numbers for each partner separately.

1
Internal Revenue Service. Answers to Frequently Asked Questions for Registered Domestic Partners and Individuals in Civil Unions
2
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
3
Internal Revenue Service. Publication 501, Dependents, Standard Deduction, and Filing Information
4
Office of the Law Revision Counsel. 26 USC 152 – Dependent Defined
5
eCFR. 26 CFR 1.106-1 – Contributions by Employer to Accident and Health Plans
6
Internal Revenue Service. Publication 936, Home Mortgage Interest Deduction
7
Internal Revenue Service. Publication 555, Community Property
8
Internal Revenue Service. Form 8958 – Allocation of Tax Amounts Between Certain Individuals in Community Property States
9
Office of the Law Revision Counsel. 26 USC 2056 – Bequests, Etc., to Surviving Spouse
10
Internal Revenue Service. Whats New – Estate and Gift Tax
11
Internal Revenue Service. Retirement Topics – IRA Contribution Limits
12
Social Security Administration. What Same-Sex Couples Need to Know
13
Internal Revenue Service. Other EITC Issues