Quick answer
To add a domestic partner to your health plan, you usually need to show that you’re in a committed relationship and share a home and finances. Most employers ask for a signed affidavit, plus documents like a joint lease or mortgage, a joint bank account, or a state domestic partnership certificate if your state offers one. Each employer or insurer sets its own rules, so ask for its checklist first.
Key takeaways
- Employers aren’t required to cover domestic partners, but many do.
- Typical requirements: 18 or older, not married to anyone else, not closely related, living together for a set time, and sharing finances.
- Common proof includes an affidavit, a shared address and joint financial accounts.
- If your partner isn’t your tax dependent, the value of their coverage is usually taxable income to you.
- Marketplace plans generally cover unmarried partners on separate applications.
On this page
Who counts as a domestic partner
Definitions vary by employer, but most require that you and your partner:
- are at least 18 and able to consent,
- aren’t married to or in a domestic partnership with anyone else,
- aren’t related by blood in a way that would bar marriage,
- have lived together for a minimum period, often 6 to 12 months,
- share responsibility for each other’s welfare and living expenses.
Documents that usually prove a domestic partnership
| Type of proof | Examples |
|---|---|
| Sworn statement | The employer’s or insurer’s domestic partner affidavit, sometimes notarized |
| State or local registration | A domestic partnership or civil union certificate, where available |
| Shared residence | A joint lease or mortgage, or utility bills or IDs showing the same address |
| Shared finances | A joint bank account or credit card, a shared loan, or naming each other as beneficiaries |
| Legal ties | Health care powers of attorney for each other, or a child you’re raising together |
State registration
Some states and cities let couples register as domestic partners or enter civil unions. In California, registered domestic partners have the same rights as spouses under state law, including for state-regulated health insurance. If you live there, see how much health insurance costs in California. Registration rules vary, and self-funded employer plans aren’t bound by state law.
Taxes on domestic partner coverage
Health coverage for a spouse or tax dependent is tax-free. If your domestic partner isn’t your tax dependent, the value of the employer-paid part of their coverage is usually added to your taxable income (called imputed income), and your share of their premium is taken out after taxes. Ask HR how much will be added to your pay stub.
Other options
If your employer doesn’t cover domestic partners, your partner can get their own coverage through their job, the marketplace or Medicaid. Unmarried partners usually apply for marketplace coverage separately, each based on their own tax household. See can I add my girlfriend or boyfriend to my health insurance and covering all family members under the same policy.
Comparing plans for yourself and a partner? See quotes by ZIP code.
Frequently asked questions
Do I have to be registered to add a domestic partner?
Not always. Many employers accept an affidavit and proof of a shared home and finances. Some require state registration where it’s available.
How long do we have to live together?
It depends on the employer or insurer. Six to 12 months is common.
Is domestic partner health coverage taxable?
Usually, unless your partner qualifies as your tax dependent. The employer-paid value of their coverage is added to your taxable income.
Sources
This article is general information, not legal or tax advice. Requirements vary by employer, insurer and state. Last reviewed September 2026.