Prenups often seem like something only celebrities or the ultra-wealthy need. But in reality, they’re useful planning tools for anyone getting married, especially in a state like California. A family law attorney can give you tips what to include and what not in your prenup.

Writing your own prenup is doable, but risky without understanding what California courts require. Let’s walk through how it works, what’s allowed, and when to bring in legal backup.

Is A DIY Prenup Legal In California?

Technically, yes, you can write your own prenuptial agreement in California. But whether that agreement will hold up in court is another matter entirely. The law doesn’t prohibit self-drafted prenups, but it does hold them to specific standards.

Full Financial Disclosure Is Required

Under California’s Uniform Premarital Agreement Act (Family Code §§ 1600–1617), both parties must provide full and honest disclosure of assets, debts, income, and liabilities before signing the prenup.

If either person hides information or even accidentally leaves something out, the entire agreement can be challenged and possibly thrown out. Transparency is one of the biggest deal-breakers in court challenges to prenups.

There Must Be Time To Review

California requires that both parties have a reasonable period of time to review the agreement before signing. That means no handing over a prenup the day before the wedding.

The law mandates at least seven days between the time one party receives the final draft and when they sign it. This is meant to prevent rushed or pressured agreements.

Any appearance of coercion can make a prenup unenforceable.

Independent Legal Counsel Is Strongly Advised

While not mandatory for both parties, California strongly encourages that each person has their own attorney before signing. In fact, if the agreement includes spousal support waivers, the court will almost always require proof that each person had legal advice.

Without it, the judge may ignore certain provisions or toss the agreement altogether.

Writing your own prenup might seem simple, but a court won’t care how much effort you put in if the document doesn’t follow the rules. Legal validity always comes before personal intent in California’s family courts.

5 Common Mistakes That Can Invalidate A Prenup

You can follow all the rules and still end up with a prenup that doesn’t hold up in court, especially if you miss a few key legal and procedural steps. Here are the most common pitfalls that turn well-meaning agreements into useless paperwork.

Rushing The Signing Process

One of the most frequent mistakes is presenting a prenup too close to the wedding date. California law requires a minimum seven-day review period, but even that can feel rushed if one party didn’t see it coming.

Courts are skeptical of any agreement signed under pressure. The closer the prenup is signed to the wedding, the more likely a judge will question its legitimacy.

One-Sided Or Grossly Unfair Terms

California courts won’t enforce prenups that are “unconscionable” at the time of signing. That means if one spouse is left with everything and the other gets nothing, not even temporary support, a judge might throw out all or part of the agreement.

Even if both parties signed willingly, fairness still matters. Judges will ask whether the deal was reasonable based on what each person brought into the marriage.

No Independent Legal Counsel

While you’re not legally required to have a family law lawyer to sign a prenup, you are if the agreement limits or waives spousal support. Without legal counsel, that clause is almost always invalid in California.

Having separate attorneys for both parties helps prove that the agreement was entered knowingly, voluntarily, and with full understanding of the consequences.

Incomplete Or Inaccurate Financial Disclosure

Leaving out income, debts, or assets, even unintentionally, can be fatal to a prenup’s validity. Both parties must provide full and accurate financial information before signing. Anything less opens the door to future challenges.

Judges assume hidden information means the agreement wasn’t fully informed.

Not Updating The Agreement When Life Changes

If your financial situation changes dramatically, due to inheritance, children, or starting a business, an old prenup might no longer make sense. Courts will still look at the original terms, so it’s smart to revise or update the agreement when major life shifts occur.

The law gives you the right to draft your own prenup, but it doesn’t excuse mistakes. Avoiding these common errors gives your agreement the legal weight you’re counting on.

What Should Be Included In A California Prenup?

A well-drafted prenup isn’t just about protecting assets; it’s about setting expectations. In California, certain topics can be legally enforced in a prenuptial agreement, while others are either restricted or outright prohibited.

Here’s a side-by-side look at what your prenup can and can’t cover:

Can Be IncludedCannot Be Enforced
Division of separate and community property.Agreements about child custody or child support.
Protection of premarital assets or debts.Waiving child support obligations in advance.
Spousal support (if both parties had independent legal counsel).Personal lifestyle rules (e.g., who does chores, how often to travel).
Estate planning terms are aligned with a will or trust.Penalties for infidelity or non-financial behavior.
Business ownership and control in the event of divorce.Agreements made under duress or signed too close to the wedding.
Provisions about retirement accounts or future earnings.Terms that are “unconscionable” or heavily one-sided at the time of signing.

California courts focus heavily on fairness, full disclosure, and voluntary agreement. You can use a prenup to protect your financial future and manage potential disputes.

You can even reinforce estate plans, but not to control parenting decisions or dictate personal conduct. If your prenup tries to include unenforceable clauses, those sections can be struck down, or in some cases, the entire agreement could be voided.

A strong prenup focuses on the financial, not the emotional. It’s a legal document, not a relationship contract, so it needs to follow the law, not just your preferences.

When Should You Start Drafting A Prenup In California?

A prenup isn’t something you want to throw together at the last minute. Timing plays a big role in whether your agreement will be enforceable and how smoothly the conversation goes.

Start The Conversation Early

Ideally, couples should begin discussing a prenuptial agreement at least three to six months before the wedding. That gives both people time to understand what they want to include, gather financial documents, and talk through any concerns.

It also keeps the process emotionally grounded. The closer you get to the wedding, the more pressure and stress you both feel, and the more likely a court might question whether one party signed under duress.

Build In California’s Required Waiting Period

California requires a minimum 7-day waiting period between when one party receives the final version of the agreement and when they sign it. That’s the bare minimum, but more time is better.

Starting early allows both partners to review drafts, make adjustments, and consult with independent legal counsel (which is especially important if the prenup includes spousal support clauses). Rushing this part can create grounds for a future challenge in court.

Don’t Let Emotions Or Deadlines Control The Process

It’s easy to put off discussing a prenup because it feels awkward or unromantic. But if you wait too long, you may end up making rushed decisions just to keep your wedding on schedule.

A rushed prenup is not just emotionally difficult; it’s also more likely to be overturned in court. Judges want to see that both parties had plenty of time and space to understand what they were signing.

If either person felt pressured or if the wedding date loomed too closely, the agreement might not hold up, even if everything else was done correctly.

Start early, stay open, and be honest about your goals. A prenup done right gives both partners peace of mind and keeps future complications to a minimum.

How Courts Decide If A Prenup Is Enforceable

Even with the best intentions, a prenup won’t help if a judge doesn’t enforce it. California courts evaluate several factors to decide whether to uphold or reject the agreement, and these checks are applied carefully.

Voluntariness & Duress

One of the first things a judge will consider is whether both parties signed the agreement willingly. If either person claims they felt pressured, whether emotionally or logistically, the court may scrutinize the timeline and context.

Was the prenup presented right before the wedding? Was there time for review? Any sign of coercion, even subtle, can affect enforceability.

Fairness & Disclosure

California law requires that both parties exchange complete financial disclosures before signing. This means full transparency about income, debts, assets, and business interests.

If either person withheld or misstated key financial details, the court may deem the prenup unfair or invalid. Judges also examine whether the agreement was “unconscionable” at the time of signing, meaning so one-sided it would be unjust to enforce.

Legal Representation & Language

While you can technically sign without a family law attorney, courts look more favorably on agreements where both parties have independent legal counsel. This is especially important for any clauses about waiving spousal support.

In addition, the language in the prenup must be clear, specific, and legally sound. Vague terms or ambiguous provisions often don’t hold up, even if both parties had good intentions.

In short, enforceability isn’t just about what’s in the prenup; it’s about how you got there. California courts protect fairness above all, especially when one spouse is more financially or legally informed than the other.

Love Is About Trust, A Prenup Is About Clarity

A well-crafted prenup doesn’t signal doubt; it shows respect for both partners and the future you’re building together. When done correctly, it creates peace of mind, not tension.

At Werno Family Law Solutions, we help couples throughout Orange County. We create prenuptial agreements that reflect fairness, transparency, and long-term protection. 

Whether you’re starting from scratch or revisiting an existing draft, we’ll walk you through every detail. So your agreement holds up in court and makes sense for your relationship.

If you’re planning to marry and want clarity about your financial future, let’s talk. Schedule a consultation with Werno Family Law Solutions, and together, we move forward with confidence. Call 714.942.5932