There is no common law marriage in Washington state. The Washington Supreme Court rejected the doctrine in 1892, and no amount of time living together, sharing finances, or calling each other spouses will make you legally married here without a license and a ceremony. What Washington does offer is a separate legal concept called a “committed intimate relationship,” which lets a court divide jointly acquired property when an unmarried couple splits up or one partner dies. The state also recognizes valid common law marriages formed in other states, and it offers a registered domestic partnership for couples where at least one partner is 62 or older.
The One Exception: Common Law Marriages From Other States
If you formed a valid common law marriage in a state that allows them and then moved to Washington, Washington will recognize your marriage. The Full Faith and Credit Clause of the U.S. Constitution drives this result, and the IRS follows the same logic, so a couple legally married under any state’s law can file joint federal returns regardless of where they currently live.1IRS. Revenue Ruling 2013-17
The catch is that the marriage has to have been valid where it was formed. You need to have met that state’s requirements, typically a present agreement to be married, cohabitation, and holding yourselves out publicly as spouses, while you actually lived there. You cannot create a common law marriage retroactively by claiming you would have qualified somewhere else.
As of 2026, the states that still permit new common law marriages are Colorado, Iowa, Kansas, Montana, New Hampshire (for inheritance purposes only), Oklahoma, Rhode Island, South Carolina, Texas, and Utah.2National Conference of State Legislatures. Common Law Marriage by State
What a Committed Intimate Relationship Does
Because common law marriage does not exist here, Washington courts developed the committed intimate relationship (CIR) doctrine to address what happens to jointly acquired property when unmarried couples separate.3Justia Law. Olver v Fowler – 2007 – Washington Supreme Court Decisions When a court finds that a CIR existed, it can divide property and debts the couple acquired during the relationship in a way that resembles a divorce proceeding.4Digital Commons. Cohabiting with Property in Washington – Washingtons Committed Intimate Relationship Doctrine
A CIR is not a back door to marriage. It does not give you inheritance rights, the ability to make medical decisions for your partner, or any federal tax benefits. It is narrowly focused on dividing property at the end of the relationship, which is exactly where unmarried couples tend to get blindsided.
How a CIR Gets Established
There is no form to fill out and no registry. A CIR is established retroactively, in court, when one partner asks a judge to recognize the relationship after a breakup or a death. Washington courts weigh five factors from the state Supreme Court’s decision in Connell v. Francisco, though no single factor is required and the list is not exhaustive:5Washington Law Review. Beyond Marvin v Marvin – How Washington Leads the Way in Protecting Unmarried Cohabitants
- Continuous cohabitation on a consistent, ongoing basis.
- Duration of the relationship. Courts do not impose a minimum number of years. A shorter relationship that quickly became stable and marriage-like can qualify, while a longer one missing other factors may not.
- Purpose of the relationship, meaning whether both partners treated it as a marriage-like commitment rather than a casual arrangement.
- Pooling of resources for shared goals, such as joint bank accounts, shared credit cards, or co-owned property.
- Intent of the parties, including whether they discussed or planned a future together.
Courts also look at whether the couple included each other in wills, named each other as beneficiaries on insurance policies, or held themselves out to friends and family as a committed couple. The analysis is heavily fact-dependent, and outcomes can vary significantly even between relationships that look similar from the outside. Most CIR claims turn into a project of assembling years of financial records, testimony from friends, and documentary evidence to prove what the relationship actually looked like.
How Property Gets Divided
When a court recognizes a CIR, it treats property acquired during the relationship much like community property in a divorce. Each partner is generally entitled to half the value of assets acquired while the couple lived together, regardless of whose name is on the title. Property one partner owned before the relationship, or received as a gift or inheritance, typically stays with that partner, the same way separate property works in a Washington divorce.
This applies whether the relationship ends through separation or through death. A surviving CIR partner already owns their share of jointly acquired property, and that share does not pass through the deceased partner’s estate or probate. Only the deceased partner’s half of the jointly acquired property, plus their separate property, can be distributed to heirs. A surviving partner who wants to claim CIR property rights after a death will almost certainly end up in court proving the relationship existed, which can be expensive and draining during an already difficult time.
What a CIR Will Not Do for You
The CIR doctrine handles property division and little else. Several rights that married couples take for granted simply do not exist for unmarried partners in Washington.
No Automatic Inheritance
Washington’s intestate succession law distributes a deceased person’s estate to a surviving “spouse or state registered domestic partner.”6Washington State Legislature. RCW 11.04.015 – Descent and Distribution of Real and Personal Estate An unmarried partner who is not a registered domestic partner is not mentioned. If your partner dies without a will, the estate goes to their children, parents, siblings, or more distant relatives, not to you. A CIR claim can protect your share of jointly acquired property, but anything that was your partner’s separate property goes to their legal heirs.
No Healthcare Decision-Making Authority
When someone cannot make their own medical decisions, Washington law assigns that authority to a priority list of family members. An unmarried partner who is not a registered domestic partner does not automatically appear on that list. Without a durable power of attorney for healthcare, your partner’s parents or adult children would make medical decisions, even if you have lived together for decades. Federal regulations do protect your right to visit your partner in the hospital, since patients can designate any visitor they choose regardless of legal relationship.7U.S. Department of Health and Human Services. FAQs on Patient Visitation at Certain Federally Funded Entities and Facilities Visitation and decision-making authority are not the same thing.
No Federal Tax Benefits
Unmarried couples cannot file a joint federal tax return. The IRS recognizes marital status as determined by state law, and since Washington does not consider you married without a license, you file as single or head of household.1IRS. Revenue Ruling 2013-17 You also miss the unlimited marital deduction on estate and gift taxes, meaning transfers between unmarried partners are taxable once they exceed the standard gift tax exclusion or lifetime exemption, while married couples can transfer unlimited assets to each other tax-free.8Legal Information Institute. Marital Deduction
There is also a hidden tax cost if your employer provides health insurance for your unmarried partner. Unless your partner qualifies as your tax dependent, the employer’s share of the premium counts as imputed income on your W-2, so you pay income tax and payroll taxes on money you never actually received. Your share of the premium must also be paid with after-tax dollars, since it cannot run through a pre-tax cafeteria plan. Registered domestic partnerships do not change this result at the federal level; only marriage or tax-dependent status eliminates the extra tax hit.
Parental Rights Do Not Depend on Marriage
Marital status has no effect on your legal rights as a parent in Washington. Under the state’s Uniform Parentage Act, a parent-child relationship “extends equally to every child and parent, regardless of the marital status of the parent.”9Washington State Legislature. Chapter 26.26A RCW – Uniform Parentage Act Married parents are automatically presumed to be legal parents, but unmarried parents need to take an extra step.
The simplest method is a voluntary acknowledgment of parentage, a signed document in which the birth parent and the other parent both affirm the parent-child relationship. The signatures must be notarized or witnessed, and both parents must be informed of the legal consequences before signing, because a signed acknowledgment carries the same legal weight as a court order establishing parentage. Challenges to the acknowledgment are barred four years after it takes effect.9Washington State Legislature. Chapter 26.26A RCW – Uniform Parentage Act Hospitals typically offer this paperwork at birth, and it can also be completed later through the state registrar of vital statistics.
Washington also recognizes a presumption of parentage for someone who lived with a child for the first four years of the child’s life and openly treated the child as their own.9Washington State Legislature. Chapter 26.26A RCW – Uniform Parentage Act If neither voluntary acknowledgment nor presumption applies, parentage can be established through a court proceeding, which may involve genetic testing.
How To Get Real Legal Protection
If common law marriage is off the table and you want more than a CIR can give you, three paths cover the range of situations.
Marriage
Marriage remains the most comprehensive way to protect both partners under state and federal law. Washington requires a marriage license, a three-day waiting period after the license is issued, and a ceremony performed by an authorized officiant in the presence of at least two witnesses.10Washington State Legislature. Chapter 26.04 RCW – Marriage The license is valid for 60 days after issuance, and the three-day waiting period cannot be waived for any reason.11King County, Washington. Marriage Licensing Both parties must be at least 18 years old. The license fee is approximately $172 as of mid-2025, following a state surcharge increase.
Registered Domestic Partnership (Age 62+)
Washington’s domestic partnership is available when both partners are at least 18 and at least one is 62 or older.12Washington State Legislature. RCW 26.60.030 – Requirements The legislature preserved this option specifically for older couples who might lose Social Security or pension benefits by remarrying. Both partners must share a common residence, neither can be married or in another domestic partnership, and neither can be a close blood relative of the other.
Under Washington law, registered domestic partners receive the same rights, benefits, and responsibilities as married spouses for all state-law purposes.13Washington State Legislature. Chapter 26.60 RCW – State Registered Domestic Partnerships That includes inheritance rights under intestate succession, healthcare decision-making authority, and community property protections.14Social Security Administration. POMS PR 05005.053 – Washington The registration fee is $50. One important limitation: federal law does not treat registered domestic partners as spouses, so you cannot file joint federal tax returns or claim the unlimited marital deduction through a domestic partnership alone.
Cohabitation Agreement and Powers of Attorney
For couples who are not ready to marry or who do not qualify for a domestic partnership, a written cohabitation agreement is the single most important protective step you can take. These contracts spell out who owns what, how expenses are shared, how property would be divided if the relationship ends, and how jointly held debts are handled. Washington courts look to the terms of such agreements when disputes arise, and having one in place is far less expensive than litigating a CIR claim after a breakup. Both partners should sign and date the agreement, and if it involves any real property, get it notarized.
Just as important, and often overlooked, is a durable power of attorney for healthcare. This document names your partner as the person authorized to make medical decisions if you cannot make them yourself. Without it, Washington’s default priority list will hand that authority to your blood relatives. A financial power of attorney serves the same function for bank accounts, bills, and other financial matters. These documents are inexpensive to prepare and can be the difference between your partner having a voice in a crisis and being shut out entirely.