Marvin Claims – Property Rights of Unmarried Partners

California does not recognize common-law marriage. Living together for any length of time, even decades, does not create community property or a right to spousal support. What unmarried partners do have is the ability to make agreements with each other, and the courts will enforce them.

In Marvin v. Marvin (1976) 18 Cal.3d 660, the California Supreme Court held that adults who live together may contract about their earnings and property, expressly or by conduct, and that such agreements are enforceable unless they rest on an exchange of sexual services. The court also recognized that a partner may recover under theories such as implied contract or quantum meruit for the reasonable value of services rendered.

A Marvin claim is a civil action, not a family law case, and it is governed by the rules of contract. The claimant must prove that an agreement existed and what its terms were. Written agreements are rare in these relationships, so the evidence is usually conduct: joint accounts, how property was titled, what the parties said to each other and to others about their arrangement, and who contributed what.

Unmarried couples who want certainty about property, especially a home, are far better served by a written cohabitation agreement than by litigating what was understood years later. Registered domestic partners are in a different position: they have the rights of spouses under California Code Family Code § 297.5.