Prenup to Protect an Inheritance in California

By Eric Ridley, attorney, Ridley Law. Updated October 2026.

If you’re getting married and you have an inheritance, or expect one, you may be wondering whether you need a prenup to protect it. Usually you don’t need one to make the inheritance yours. A prenup is worth considering when you expect to mix the money into married life, when the inheritance is large compared with everything else you own, or when you want the death-side rules to come out a particular way. For what a prenup can do to a will or trust, see whether a prenup overrides a will or trust, and for the property categories, separate property and community property.

The law already protects the inheritance, and what puts it at risk

Separate property of a married person includes property acquired after marriage by gift, bequest, devise or descent, and the rents, issues and profits of that property (Fam. Code, § 770(a)(2), (3)). Other property acquired during marriage while you live in California is community property unless a statute says otherwise (Fam. Code, § 760).

Take a hypothetical spouse who inherits $400,000 and uses all of it as the down payment on a $1,000,000 house, with a $600,000 mortgage. The house is titled in both spouses’ names. Years later the couple divorces. The house is worth $1,600,000, the mortgage is still $600,000, and the net equity is $1,000,000. Assume the court divides the community estate equally. These numbers are invented to show how the statutes work.

For a division on divorce, property acquired during marriage in joint form is presumed to be community property. The presumption can be rebutted by a clear statement in the deed that the property is separate, or by proof of a written agreement that it is (Fam. Code, § 2581). The inheriting spouse still has a claim. A spouse who traces contributions to the acquisition of community property to a separate property source is reimbursed for them, unless the spouse has signed a waiver of reimbursement or a writing that has that effect (Fam. Code, § 2640(b)). The reimbursement comes without interest or adjustment for changes in value, and it can’t exceed the net value of the property at the time of division. So the inheriting spouse gets the $400,000 back first, and the remaining $600,000 of equity is split, $300,000 each. That’s $700,000 for the inheriting spouse and $300,000 for the other.

Suppose instead that the inheritance went into a joint checking account, mixed with both spouses’ paychecks, and the down payment came out of that account. If the inheriting spouse can’t trace the down payment to the inheritance, no reimbursement is available, and the equity splits $500,000 each. The inheritance was identical in both versions. Tracing made the $200,000 difference.

The two ways an inheritance becomes shared

Separate property turns into community property in two different ways, and the law treats them differently.

Mixing it with community money

California puts the burden on the spouse who mixes. In See v. See (1966) 64 Cal.2d 778, a divorce case about a husband’s separate funds deposited into accounts with community earnings, the Supreme Court said property bought during marriage is presumed community and the spouse claiming it is separate has to overcome the presumption. The court added that a spouse may protect separate property by not commingling it, and that once a spouse commingles, the spouse takes on the burden of keeping records good enough to trace it. Where funds can’t be traced, the community presumption controls. The statute that governs written transmutations says it doesn’t affect the law on property where separate and community property are commingled (Fam. Code, § 852(d)), so the transmutation statute does not displace that rule.

In practice, tracing means statements. The inheritance wires into an account that has nothing else in it, and the account is used for nothing else. When you do spend it, you can show where it went.

Signing something that says it’s shared

A transmutation of property between spouses isn’t valid unless it’s in writing, by an express declaration made, joined in, consented to or accepted by the spouse whose interest is adversely affected (Fam. Code, § 852(a)). Transmuting real property doesn’t bind third parties without notice unless it’s recorded (§ 852(b)). The Supreme Court read the express-declaration requirement strictly in Estate of MacDonald (1990) 51 Cal.3d 262. A writing isn’t an express declaration unless it contains language that expressly states that the characterization or ownership of the property is changing. A wife’s signed consent paragraphs on IRA adoption agreements, which held pension money she had a community interest in, didn’t qualify, because nothing on their face said the signer was changing the character or ownership of her interest.

That rule protects you from the casual transmutation. A casual statement that the money is “ours” doesn’t state that the character or ownership is changing. A signed trust, loan document or deed that does contain the words is another matter, and it can change the character of property you thought was safe. Read the characterization language before you sign, and see transmutation agreements and trust assets for how those documents work.

For what happens when this goes wrong inside a trust, see commingled assets in trust administration and community property versus separate property in trust administration.

What a prenup adds

A premarital agreement is an agreement between prospective spouses, made in contemplation of marriage, that takes effect on marriage (Fam. Code, §§ 1610(a), 1613). Parties can contract about their rights in any property of either of them, whenever and wherever acquired. They can also agree on what happens to property on separation, divorce or death, and on making a will, trust or other arrangement to carry out the agreement (Fam. Code, § 1612(a)(1), (3), (4)). “Property” under the chapter includes a future or contingent interest, and income and earnings (§ 1610(b)). That language is why a prenup can address an inheritance you expect but haven’t received.

In practice, the agreement can say the inheritance, its income and anything bought with it are separate, say how contributions to a shared asset get repaid, and say that neither spouse’s casual conduct changes the character of property. The agreement can waive the reimbursement right in § 2640, but only if the waiver is written, so be careful with what you waive. That’s the part most worth reading line by line.

A prenup doesn’t do everything. It can’t affect a child’s right to support, and a spousal support waiver isn’t enforceable if the spouse it’s enforced against didn’t have independent counsel when signing or if the provision is unconscionable at enforcement (Fam. Code, § 1612(b), (c)). It doesn’t bind your parents either. If your parent wants to leave you money in a way that survives a divorce, that depends on how your parent’s trust is written, which is the next section.

On the death side, a spouse can waive rights in the other’s estate, including the omitted spouse’s share, a probate homestead and family allowance, and an interest in nonprobate transfers (Prob. Code, § 141(a)). A premarital property agreement that affects those rights is judged under the law that otherwise applies to premarital agreements, which is the Family Code chapter described below, not the Probate Code waiver rules (Prob. Code, § 147(c)). A separate waiver made under the Probate Code chapter has to be in writing and signed by the surviving spouse (§ 142(a)), and it’s enforceable under § 143 or § 144. The prenup and will page covers how the prenup and the will or trust have to agree.

Making the prenup hold up

A premarital agreement must be in writing and signed by both parties, and it needs no consideration (Fam. Code, § 1611). It isn’t enforceable if the person it’s enforced against proves they didn’t sign voluntarily, or that it was unconscionable when signed and that person had no fair, reasonable and full disclosure, hadn’t waived disclosure in writing, and didn’t have adequate knowledge of the other person’s property and obligations (Fam. Code, § 1615(a)). Unconscionability is for the judge to decide (§ 1615(b)).

The voluntariness test is the one that fails. Section 1615(c) says an agreement is deemed not voluntary unless the court finds each of a list of things in writing or on the record. The list includes independent counsel for the person it’s enforced against at signing, or an express waiver of counsel, in a separate writing, after being advised to seek it. The advisement has to come at least seven calendar days before the final agreement is signed (§ 1615(c)(1)). For an agreement signed on or after January 1, 2020, that person must also have had at least seven calendar days between first being presented with the final agreement and signing, whether or not represented. The seven days don’t apply to nonsubstantive amendments (§ 1615(c)(2)(B)). The two seven-day periods are separate requirements, so a late advisement can fail even when the draft arrived early, and the reverse.

If the person isn’t represented, the agreement needs more. The unrepresented person must be fully informed of the terms and basic effect and of the rights and obligations given up, and must be proficient in the language of the explanation and the agreement. The explanation must be written and delivered before signing, and that person must sign, on or before signing the agreement, a document declaring they received it and saying who provided it (§ 1615(c)(3)). The court must also find that the documents weren’t signed under duress, fraud or undue influence and that no one lacked capacity (§ 1615(c)(4)).

After the wedding, the agreement can be amended or revoked only by a written agreement signed by the parties (Fam. Code, § 1614). Plan the calendar backward from the wedding, not forward from the engagement. For an agreement signed on or after January 1, 2020 inside the seven-day window (other than a nonsubstantive amendment), the court can’t make the findings § 1615(c) requires, and without them the agreement is deemed not voluntary. Ridley Law drafts premarital agreements and coordinates them with the estate plan, so the two documents are written to match and read side by side. Ridley Law represents one party to the agreement. The other party needs separate, independent counsel, or has to sign an express waiver of counsel in a separate writing after being advised to seek it, with that advisement made at least seven calendar days before the final agreement is signed (Fam. Code, § 1615(c)(1)). The lawyer who drafts for one spouse can’t also be the other spouse’s independent counsel.

Protections that don’t depend on your spouse

Most of the daily work of protecting an inheritance happens outside the prenup.

• Open an account in your name alone for the inheritance and use it for nothing else. Don’t add your spouse, and don’t deposit paychecks.
• Keep statements. If you buy something with the money, buy it from that account and keep the closing documents.
• Be careful with title. A house titled in both names is the kind of joint-form property § 2581 presumes to be community property on divorce.
• Read every deed, loan document and trust before you sign. Look for a sentence that characterizes the property, and ask what it does.
• Tell your lawyer about an expected inheritance before the wedding. A prenup can address an interest that’s future or contingent (Fam. Code, § 1610(b)).

If you haven’t married yet, the prenup is the document. If you’re already married and the inheritance is already in hand, a prenup isn’t available, because the statute defines it as an agreement between prospective spouses. A written agreement between the spouses, with the express declaration § 852 requires, is the tool, and the transmutation page explains it.

Your own living trust deserves a careful look. Community property transferred in trust remains community property during the marriage if the trust is revocable as to it and meets the conditions in Fam. Code, § 761(a). The trust doesn’t turn community property into separate property. Whether the trust document keeps inherited property separate depends on what it says. It should list the inheritance as yours and shouldn’t contain a sentence that does the opposite. If the trust you’re drafting is the question, see estate planning after marriage and the blended family estate plan.

The best protection for an inheritance often comes from the person leaving it. A parent can leave money in trust instead of outright. If the trustee has sole discretion over payments, your creditors can’t compel a payment (Prob. Code, § 15303(a)), and a spendthrift clause shields your interest in income and principal until it’s paid to you (Prob. Code, §§ 15300, 15301). Those sections deal with creditors. A court can also order the trustee to pay a support judgment for a spouse, former spouse or minor child out of the trust (Prob. Code, § 15305), and none of the rules says how a distribution is characterized once you receive it. Keep distributions in your own account, because the tracing rules above apply to what you receive. If you’re a parent planning to leave a child money, see second marriage and the family house and spendthrift trusts and creditor protection.

Frequently asked questions

Is an inheritance separate property in California?

Yes. Property a married person acquires after marriage by gift, bequest, devise or descent is separate property, along with the rents, issues and profits of that property (Fam. Code, § 770(a)(2), (3)). It stays separate unless it is mixed with community money in a way you can’t trace, put into joint title, or transmuted by a signed writing that expressly changes its character (Fam. Code, §§ 852, 2581).

Do I need a prenup to protect my inheritance?

Not to make the inheritance separate, because the statute already does that. A prenup helps when you expect to mix the money into joint accounts or joint-title property, when the inheritance is large relative to other assets, or when you want specific rules at divorce and death. A premarital agreement can address rights in property whenever acquired, including a future or contingent interest (Fam. Code, §§ 1610(b), 1612(a)(1)).

What makes a California prenup unenforceable?

The person it’s enforced against can defeat it by proving they didn’t sign voluntarily, or that it was unconscionable and they hadn’t received fair disclosure or waived it (Fam. Code, § 1615(a)). An agreement is deemed involuntary unless the court finds, among other things, independent counsel or a written waiver, advice to get counsel at least seven calendar days before signing, and at least seven days with the final agreement (§ 1615(c)).

Does the seven-day rule apply if both of us have lawyers?

Yes, for an agreement signed on or after January 1, 2020. The person the agreement is enforced against must have had at least seven calendar days between first being presented with the final agreement and signing it, whether or not they have a lawyer. Nonsubstantive amendments don’t restart the period (Fam. Code, § 1615(c)(2)(B)). A separate rule requires advice to get independent counsel at least seven calendar days before signing.

What happens if I put my inheritance in a joint account?

You risk losing the ability to prove it was separate. California presumes property bought during marriage is community, and a spouse who commingles separate and community funds has the burden of tracing (See v. See (1966) 64 Cal.2d 778). Property bought during marriage in joint form is presumed community (Fam. Code, § 2581), though a spouse who can trace contributions may be reimbursed under § 2640.

Can I protect an inheritance after I’m already married?

A premarital agreement has to be made before the wedding (Fam. Code, § 1610(a)). After marriage, the tools are keeping the money in an account in your name alone, keeping records, and, if you and your spouse agree, a written transmutation with an express declaration that meets Fam. Code, § 852(a). A court reads that writing strictly, so the language has to state the change expressly (Estate of MacDonald (1990) 51 Cal.3d 262).

Does a prenup control who inherits when I die?

A prenup can include a waiver of the surviving spouse’s rights in your estate (Prob. Code, § 141(a)). A premarital agreement that affects those rights is judged under the law that applies to premarital agreements, which means Fam. Code, § 1615 (Prob. Code, § 147(c)). A separate waiver signed under the Probate Code must be in writing, signed by the surviving spouse and enforceable under § 143 or § 144 (Prob. Code, § 142). Neither can force your will or trust to leave your spouse anything. The will or trust has to be written to match.