Postnuptial Agreements in Washington State: What You Need to Know

Considering a postnuptial agreement? While less talked about than prenups, a postnuptial agreements in Washington State (or “postnups”) can play a crucial role in protecting your financial future—especially if circumstances in your marriage have changed. At Weintraub Law Office, PLLC, our experienced Seattle postnuptial agreements lawyer provides trusted guidance and drafts enforceable postnuptial agreements (or “postnups”) that play a crucial role in protecting your financial future—especially if circumstances in your marriage have changed.

At Weintraub Law Office, PLLC, our experienced Seattle postnuptial agreements lawyer helps couples across King and Snohomish Counties create sound, enforceable agreements that clarify financial rights and reduce conflict.

What Is a Postnuptial Agreement?

A postnuptial agreement is a legal contract between spouses entered into after marriage. It outlines how assets, debts, property, or even spousal support would be handled in the event of divorce or death.

Unlike a prenuptial agreement (signed before the wedding), a postnup is done after you’re already legally married.

Why Do Couples Consider a Postnup?

• A business grows significantly during the marriage.
• One spouse receives a large inheritance and wants to keep it separate.
• Marital challenges arise and you want to clarify terms without divorcing.
• Blended families wish to protect children from prior relationships.
• Financial roles shift, such as one spouse leaving work to raise children.

Are Postnuptial Agreements Enforceable in Washington?

Yes—but Washington courts scrutinize postnups more closely than prenups. To be enforceable, a postnup must:

• Be voluntary, with no coercion.
• Include full financial disclosure by both spouses.
• Be fair and reasonable at the time of signing.
• Be in writing.
• Be reviewed by independent legal counsel (highly recommended).

What Can Be Included in a Postnup?

A well-drafted postnuptial agreement can address:

• Division of marital vs. separate property.
• Business ownership and income.
• Responsibility for debts and liabilities.
• Spousal support (alimony).
• Real estate, investment accounts, and retirement funds.

Note: Child custody and child support cannot be addressed in a postnup—they must comply with Washington law at the time of divorce.

When a Postnup May Not Hold Up

Washington courts may invalidate a postnup if:

• A spouse was not represented by an attorney to advise and inform them, and didn’t understand the terms
• There was pressure or manipulation (coercion).
• There was not full financial disclosure (e.g., on party hid major assets).
• The agreement is grossly unfair (“unconscionable”).

Postnups as an Alternative to Last-Minute Prenups

If a wedding is approaching quickly and there isn’t sufficient time for one or both parties to fully review, understand, and obtain legal advice regarding a prenuptial agreement, the enforceability of that prenup may be at risk. In such cases, a postnuptial agreement can serve as a safe and legally sound alternative. It allows spouses to enter into a financial agreement after marriage—under conditions that are more likely to meet Washington’s legal requirements for fairness and enforceability.

For a deeper look at the legal standards for prenups, visit our guide on What Makes a Prenuptial Agreement Valid in Washington state.

How Weintraub Law Can Help

At Weintraub Law Office, PLLC, we help clients:

• Decide whether a postnup is right for their situation.
• Ensure agreements are not ruled “unconscionable” by drafting agreements that are clear, balanced, and enforceable.
• Ensure all necessary financial disclosure is made.
• Review and revise existing postnups.

We offer affordable rates tailored to the complexity of your case, with clear billing and no surprise fees..

Serving Seattle, Bellevue, and Surrounding Areas

We assist clients throughout Seattle, Bellevue, Bothell, Kirkland, and across King and Snohomish counties.

Book a Free Consultation

Thinking about a postnuptial agreement? Speak with a trusted Seattle postnuptial agreements lawyer today. We’ll walk you through your options and ensure your agreement meets Washington legal standards.

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Frequently Asked Questions

Can we create a postnup without lawyers?

You technically can, but it’s very risky—especially under Washington State’s two-pronged rule. If a postnuptial agreement is not fair on its face, it will not be enforced unless certain conditions are met including full disclosure of all assets and debts, and each spouse having the advice and counsel of their own independent attorney. Without meeting these legal safeguards, courts are unlikely to uphold the agreement.

What’s the difference between a postnup and a separation contract?

A postnup is for couples who intend to remain married. A separation contract is typically used when preparing for legal separation or divorce.

Can we include an infidelity clause?

Some couples include “lifestyle clauses,” but courts may not enforce them if they’re considered punitive or irrelevant to financial fairness.