A cohabitation agreement in California is a contract between unmarried partners that spells out how they’ll handle property, debts, shared expenses, and financial support if the relationship ends. California doesn’t recognize common-law marriage, so no matter how long you live together, you never acquire automatic rights to each other’s earnings or property. The 1976 California Supreme Court decision in Marvin v. Marvin confirmed that unmarried partners can enter enforceable contracts about their finances, but those protections only exist if you actually create them.1Justia. Marvin v. Marvin (18 Cal. 3d 660)
What the Agreement Can Cover
The core job is spelling out who owns what. You can identify which assets each partner brought into the relationship and confirm they stay separate. You can also decide in advance how jointly acquired property — a home, a car, a shared savings account — will be divided if you separate. Without that clarity, a breakup can turn into a lawsuit where a judge tries to reconstruct what the two of you intended.
Debt allocation deserves the same treatment. The agreement can say that each partner remains responsible for debts they came in with and lay out how you’ll split debts you took on together. Creditors aren’t bound by your private arrangement, so this section mainly governs what you owe each other, not what a lender can collect from either of you.
Day-to-day expenses are another common feature. You can agree to split rent or mortgage payments, utilities, and groceries equally or in proportion to income. Putting this in writing prevents the slow-building resentment that comes from one partner quietly subsidizing the other.
Post-separation financial support can be included or explicitly excluded. In Marvin, the court recognized an agreement where one partner gave up a career in exchange for lifetime support from the other.1Justia. Marvin v. Marvin (18 Cal. 3d 660) If one of you plans to reduce work hours or leave the workforce for the household’s benefit, this is where that tradeoff gets documented.
The agreement can also address what happens if one partner dies: how jointly held assets transfer and whether the surviving partner has any claim on the deceased partner’s estate. These provisions work alongside a will or trust, not in place of them.
What the Agreement Cannot Cover
Custody and child support can’t be locked in by contract. California courts decide both issues at the time of separation based on the best interest of the child, weighing factors like each parent’s health, any history of abuse, substance use, and the child’s existing relationship with each parent.2California Legislative Information. California Family Code 3011 – Best Interest of Child A judge won’t defer to what you wrote years earlier.
The agreement also can’t rest on an exchange of support for sexual services. The Marvin court was explicit that courts will enforce contracts between unmarried partners “except to the extent that the contract is explicitly founded on the consideration of meretricious sexual services.”1Justia. Marvin v. Marvin (18 Cal. 3d 660) The consideration has to be the couple’s financial and property arrangement.
A court can also refuse to enforce any provision it finds unconscionable. If a clause was fundamentally unfair at the time of signing, the court can strike it or decline to enforce the whole contract.3California Legislative Information. California Civil Code 1670.5 An agreement that leaves one partner with nothing after a long relationship while the other keeps everything is the kind of provision that invites a challenge.
What Makes It Enforceable
California doesn’t technically require a cohabitation agreement to be in writing. The Marvin court noted that most of the enforced agreements between unmarried partners had been oral and rejected the argument that the statute of frauds barred such claims.1Justia. Marvin v. Marvin (18 Cal. 3d 660) Relying on an oral agreement is still a bad idea. Proving what two people said to each other years ago, when memories differ and emotions run high, is exactly the fight you’re trying to avoid. Put it in writing and sign it.
Both signatures must be voluntary. If either partner signed under duress, fraud, or undue influence, California law allows the contract to be rescinded.4California Legislative Information. California Civil Code 1689 Presenting a finished draft the night before a move-in and pressuring your partner to sign is the kind of scenario that can sink the document later. Both people need time to read, ask questions, and think.
Full financial disclosure is essential. Before signing, both partners should share a complete picture of assets, debts, and income. If a court later finds that one partner hid significant assets, that omission alone can void the agreement.
Each partner should also have their own attorney review the document. It’s not legally required, but it’s the single most effective way to make the agreement stick. When each person has received independent advice about what the terms mean for them specifically, it becomes much harder for either side to argue later that they didn’t understand what they were signing.
Domestic Partnership as an Alternative
Before committing to the contract route, know what a California registered domestic partnership offers, because it may accomplish some of what you’re trying to build. Registered domestic partners receive the same rights, protections, and obligations as married spouses under California law.5California Legislative Information. California Family Code 297.5 That includes community property rules, mutual support obligations, and the right to divide property through family court if the partnership ends.
To register, both partners must be at least 18, neither can be married or in another domestic partnership, and both must be capable of consenting.6California Legislative Information. California Family Code 297 You file a Declaration of Domestic Partnership with the Secretary of State.7California Secretary of State. Frequently Asked Questions – Domestic Partners Registry
The tradeoff is real. Community property means earnings during the partnership belong equally to both partners, and ending it requires a legal dissolution similar to divorce. A cohabitation agreement lets you customize the arrangement instead of taking the whole spousal package. Some couples register as domestic partners and also sign a cohabitation agreement to modify specific default rules. The right choice depends on how much legal structure you want around the relationship.
Gaps No Contract Can Close
A cohabitation agreement can’t fix every disadvantage of being unmarried. Several federal rules create financial consequences that no private contract can override, and understanding them helps you plan around them.
Income Tax Filing
Unmarried partners must file federal income taxes as single filers or, if they have a qualifying dependent, as head of household.8Internal Revenue Service. Filing Status You cannot file jointly regardless of how intertwined your finances are.
Property transfers between unmarried partners can also trigger taxes that married couples avoid. Federal law allows tax-free transfers of property between spouses and between former spouses as part of a divorce, but that rule doesn’t extend to unmarried partners.9Office of the Law Revision Counsel. 26 U.S. Code 1041 – Transfers of Property Between Spouses or Incident to Divorce If your agreement requires transferring an appreciated asset at separation, that transfer can create a taxable event. Involve a tax professional when drafting provisions like this.
Retirement Accounts
Under most employer-sponsored retirement plans, benefits automatically pass to a surviving spouse, and naming a different beneficiary requires the spouse’s written, witnessed consent.10Office of the Law Revision Counsel. 29 U.S. Code 1055 – Requirement of Joint and Survivor Annuity and Preretirement Survivor Annuity If you’re unmarried, none of that applies. Your partner receives nothing from your retirement plan unless you affirmatively name them as beneficiary. A cohabitation agreement can promise to maintain beneficiary designations, but the actual designation on the plan’s paperwork is what controls.
Social Security Survivor Benefits
Social Security survivor benefits are available to widows, widowers, and surviving divorced spouses who were married at least ten years, but not to unmarried partners regardless of how long the relationship lasted.11Office of the Law Revision Counsel. 42 U.S. Code 402 No contract can change federal benefit eligibility. If one partner earns significantly more, this gap is a long-term risk the lower earner should account for in their own retirement planning.
Companion Documents You Still Need
A cohabitation agreement addresses finances between the two of you. It doesn’t give your partner the authority to make medical decisions for you, and it doesn’t guarantee they’ll inherit anything.
Without an advance healthcare directive, California law dictates who makes medical decisions if you’re incapacitated, and an unmarried partner often ranks below relatives you may not be close to. California’s statutory advance directive form lets you name your partner as your healthcare agent.12California Legislative Information. California Probate Code 4701 It’s a straightforward document to complete.
On inheritance, unmarried partners have no automatic rights in California. If your partner dies without a will, everything passes to blood relatives under intestacy rules. Even with a will, unmarried partners don’t qualify for the federal estate tax marital deduction that allows spouses to transfer unlimited assets tax-free at death. A cohabitation agreement can express intent, but a will, trust, and up-to-date beneficiary designations are what actually move assets. Draft the cohabitation agreement and your estate plan together.
How to Create the Agreement
Start with an honest conversation about finances before anyone drafts anything. Exchange complete information on income, assets, and debts. This is the foundation of the full disclosure requirement, and treating it as a formality is where many agreements start to fail.
Once you’ve agreed on the key terms, have a qualified California family law attorney draft the document. Templates exist, but a cohabitation agreement is only as useful as its enforceability, and an attorney familiar with California case law since Marvin will know which provisions courts uphold and which they routinely strike down.
Each partner should then take the draft to their own separate attorney for review. Your drafting attorney represents the couple’s shared interests; your review attorney represents you alone and can flag terms that put you at a disadvantage. This step is the strongest evidence of voluntariness if the agreement is ever challenged.
Sign the final version after both attorneys are satisfied. Notarization isn’t legally required, but having a notary witness the signatures makes it harder for either side to later claim a signature was forged or improperly obtained. Each partner should keep a signed original.
Keeping It Current
A cohabitation agreement isn’t a set-it-and-forget-it document. One partner starts a business, you buy a house together, a child arrives, income shifts dramatically. An agreement written when you were both renting and splitting expenses evenly may not make sense five years later when one of you owns a home and the other has tripled their salary.
Any changes should be made through a written amendment signed by both partners, following the same basic process as the original: full disclosure, adequate time to review, and independent legal advice. Verbal agreements to modify the original terms carry the same risks as any verbal contract. Set a regular interval to review the agreement together, even just to confirm it still reflects where you both are.