California’s new marriage laws center on three recent changes: as of January 1, 2025, no one under 18 can marry in the state; couples who agree on their divorce terms can now file a single joint dissolution petition instead of the traditional petition-and-response sequence; and, since January 1, 2020, any two adults aged 18 or older can register as domestic partners. Two related updates round out the picture — stricter procedural rules for prenuptial agreements signed on or after January 1, 2020, and a federal tax change that removed the deduction for spousal support in divorces finalized after 2018.
Minimum Marriage Age Is Now 18
For decades, California had no minimum marriage age. A minor could marry with parental consent and a judge’s approval, which put California among a small group of states without a floor. AB 2924 changed that. Effective January 1, 2025, the law repealed Family Code Sections 302 and 303, which had authorized county clerks to issue marriage licenses to people under 18.1LegiScan. California AB 2924 2023-2024 Regular Session
Under the new rule, any marriage where one party was under 18 at the time of the ceremony is voidable, unless it was entered under the former provisions before the January 1, 2025 cutoff. Nine states had already enacted absolute bans on underage marriage before California joined them. Advocates had been pushing for this change since at least 2017, when an earlier bill was weakened during the legislative process.
The ban applies equally to domestic partnerships. No one under 18 can register a domestic partnership in California either. There is no longer any parental-consent or judicial-approval pathway around the age requirement.
Joint Dissolution Petitions
SB 1427, part of the same 2025 legislative cycle, gives couples who agree on the terms of their divorce a new procedural option. Under the traditional process, one spouse files a petition and the other is served and files a response. The joint petition collapses that into one filing signed by both spouses.
This skips the formal service requirement and eliminates the need for a separate response. For couples who have already worked out property division and support arrangements, that can shorten the timeline and reduce legal costs. Couples who disagree on any of the terms still use the standard petition-and-response process.
Domestic Partnerships Open to All Adults
Since January 1, 2020, California has allowed any two adults to register as domestic partners regardless of sex, as long as both are at least 18. SB 30 removed the previous restrictions that limited domestic partnerships to same-sex couples, or to opposite-sex couples where at least one partner was 62 or older.2California State Controller. Domestic Partnership FAQs The expansion gives couples an alternative to marriage that carries the same state-level rights and obligations.
To register, both people must be unmarried and not already in another domestic partnership. Neither can be related by blood in a way that would prevent them from marrying, and both must be capable of consenting.3California Secretary of State. Domestic Partners Registry Frequently Asked Questions Registration goes through the California Secretary of State’s office rather than a county clerk. The registration forms must include an explanation that domestic partners receive the same rights and obligations as married spouses under state law.
Ending a domestic partnership follows the same process as divorce, including financial disclosures, property division under community property rules, and potential support. A simplified dissolution option exists for short partnerships without children or significant shared assets; otherwise the process mirrors marital dissolution.
Prenuptial Agreements: The Seven-Day Rule
For prenuptial agreements signed on or after January 1, 2020, California added procedural safeguards that apply whether or not each party hires a lawyer. The person signing must have at least seven calendar days between receiving the final agreement and signing it.4California Legislative Information. California Family Code FAM Section 1615 Before that window even starts, the person must be advised to seek independent legal counsel.
If they choose not to hire a lawyer, they must waive that right in a separate written document, and they must receive a written explanation of the terms they’re giving up in a language they can fully understand. The underlying enforceability rules haven’t changed: a prenup is unenforceable if the person challenging it can show they didn’t sign voluntarily, or that the agreement was unconscionable and they didn’t receive adequate financial disclosure beforehand.
One boundary worth noting. Under federal ERISA rules, a prenup signed before marriage cannot effectively waive survivor benefits in a qualified pension or 401(k) plan. Federal law requires that the waiver be executed by a spouse, meaning after the wedding. Couples who include retirement waivers in a prenup often need to confirm those waivers in a postnuptial agreement to make them enforceable.
Spousal Support Is No Longer Tax-Deductible
This one is federal rather than state, but it changed the financial reality of every California divorce finalized after December 31, 2018. Spousal support payments are neither tax-deductible for the payer nor taxable income for the recipient. Under the Tax Cuts and Jobs Act, the old treatment flipped, and it altered the calculus of support negotiations because the payer no longer gets a deduction to offset the outflow.
Older agreements from before 2019 still follow the prior rules, where the payer deducted payments and the recipient reported them as income. If you’re negotiating support now, or modifying an older order, the tax treatment depends on when the order was finalized.
What Hasn’t Changed
The core framework around marriage in California is the same as it has been for years. Both people still apply together in person at a county clerk’s office with valid photo ID, the license is valid for 90 days from issuance, and a public marriage still requires at least one witness in addition to the couple and officiant.5Sacramento County Clerk/Recorder. Apply for a Marriage License Confidential marriage licenses remain available to couples who are both 18 or older and have been living together as spouses.6San Mateo County Assessor-County Clerk-Recorder. What Is the Difference Between a Confidential and a Public Marriage License
California’s community property rules under Family Code Section 760 continue to govern property acquired during marriage,7California Legislative Information. California Family Code Section 760 and the spousal support factors in Family Code Section 4320 still guide judges’ decisions on amount and duration.8California Legislative Information. California Family Code Section 4320 The fiduciary duty of full financial disclosure during divorce, and the 60-day deadlines for serving preliminary declarations of disclosure, are unchanged.9California Legislative Information. California Family Code FAM Section 2104
If you’re planning a wedding, entering a domestic partnership, or negotiating a prenup in California, the recent changes to watch are the flat age-18 rule, the joint dissolution option if a marriage ends amicably, the broadened domestic partnership eligibility, and the seven-day waiting period built into prenuptial agreements. Each one narrows or expands a choice that used to work differently, and each one takes effect regardless of what your paperwork or your county clerk did before.