Community Property States: Tax and Estate Planning for Married Couples (2026)

If you live in one of the 9 community property states — or have ever moved between states — your financial planning works differently. The double step-up in basis alone can save a surviving spouse hundreds of thousands in capital gains taxes. But commingling separate and community assets can accidentally eliminate that protection, and filing married-separately requires splitting income in a way that surprises most couples. This guide covers the planning implications your advisor needs to address.

The 9 community property states (and one opt-in)

Nine states treat marital income and assets as jointly owned community property. Alaska allows couples to opt in to community property treatment voluntarily via a written agreement.

All other states follow common-law (equitable distribution) rules, where each spouse owns what they earn and what is titled in their name. The states differ materially in how property is divided at divorce and the tax treatment at death.

Community property vs. separate property

The classification matters enormously for taxes and estate planning.

What is community property

• All wages and salary earned by either spouse during the marriage
• All assets purchased with community income (real estate, brokerage accounts, retirement account contributions made during marriage)
• Business income generated during marriage from a jointly-operated enterprise
• In Idaho: income earned on separate property is community property

What is separate property

• Assets owned before the marriage and kept separate
• Gifts received by one spouse individually during the marriage
• Inheritances received by one spouse individually
• In most CP states: income and appreciation on separate property remain separate (Idaho is an exception)

The commingling trap

Separate property loses its protected status the moment it gets mixed with community assets in a way that makes it impossible to trace. Common mistakes:

• Depositing an inheritance into a joint checking account that community income flows through
• Using separate property funds to make mortgage payments on a community-owned home (creates a "reimbursement claim" but also reduces traceability)
• Titling a pre-marital account in both spouses' names without documentation that it was originally separate property

Once commingled, property defaults to community status. If you received an inheritance and want to keep it separate, open a dedicated separate-property account, document the deposit, and do not mix community funds into it. A fee-only advisor can help you structure this correctly before the money moves.

The double step-up in basis: the biggest planning advantage

This is the single most financially significant difference between community property and common-law states, and it is often missed until after the first spouse dies.

How the step-up works in common-law states

In common-law states, each spouse owns their own half of jointly held assets. When one spouse dies, only the deceased spouse's half of the asset receives a step-up in basis to fair market value. The surviving spouse's half retains its original (often much lower) cost basis.

Example (New York couple, common-law state): A couple bought stock for $100,000 in 2010. In 2026 it is worth $600,000. One spouse dies. The surviving spouse's original $50,000 half retains its basis. The deceased spouse's $50,000 half gets stepped up to $300,000. Combined basis after death: $350,000. If the surviving spouse sells the stock, they owe capital gains tax on $250,000 of gain ($600,000 − $350,000).

How the step-up works in community property states

Under IRC § 1014(b)(6), when one spouse in a community property state dies, both halves of community property receive a full step-up in basis to fair market value at the date of death.¹ The surviving spouse's share is included too — even though the surviving spouse did not die.

Same example (California couple, community property state): Same stock, bought for $100,000 in 2010, worth $600,000 at death in 2026. Both halves step up. The surviving spouse's entire position now has a $600,000 basis. If they sell immediately, zero capital gains tax.

For couples with a highly appreciated taxable brokerage account, concentrated employer stock, real estate purchased decades ago, or a business interest accumulated during marriage, the double step-up is worth modeling explicitly. It is one of the most powerful and permanent tax advantages in the tax code.

CPWROS: locking in the double step-up

In Nevada, Texas, and some other CP states, couples can hold assets as Community Property with Right of Survivorship (CPWROS). This title combines the double step-up benefit with automatic transfer at death (like joint tenancy) — without going through probate. In California, standard community property also passes without probate if held in a revocable trust, but CPWROS is a simpler alternative for specific assets.

Not all assets can be titled as CPWROS. Real estate and brokerage accounts are the most common candidates. Talk to an estate planning attorney about whether CPWROS makes sense for your specific assets and state.

Tax filing implications for married couples in CP states

Married filing jointly (MFJ): no change

If you file jointly, community property rules do not change how you prepare your federal return. MFJ already reports all household income on one return. Community property classification is irrelevant at the form level.

Married filing separately (MFS) in a community property state: big change

This is where couples get surprised. In common-law states, MFS is simple: Spouse A reports their income, Spouse B reports theirs. In a community property state, each spouse must report half of all community income on their separate MFS return — regardless of whose paycheck generated it, per IRS rules for community property states.²

IRS Form 8958 is used to allocate income in community property states when filing MFS. Each spouse reports half of community wages, interest, dividends, and other community income, and half of community deductions.

This community income splitting can make MFS more or less attractive depending on your situation. MFS in a CP state can equalize income between spouses — potentially reducing overall tax if you are targeting a specific bracket. But MFS also triggers many unfavorable tax rules (no Roth IRA direct contribution, no student loan interest deduction, limits on passive activity losses). See our MFJ vs MFS calculator to model your specific numbers.

Community property and IRMAA

IRMAA surcharges for Medicare Part B and Part D are based on your MAGI from two years prior. In community property states, MFS returns split income equally — which means if one spouse has high Medicare costs and you are considering filing MFS to reduce their MAGI, the community property income-splitting rule may prevent the split from working the way you expect. Both spouses end up with the same MAGI regardless of actual earnings. See our IRMAA calculator for 2026 thresholds.

Estate planning differences in community property states

Wills and trusts matter more

In common-law states, assets held jointly with right of survivorship pass automatically to the surviving spouse. In community property states, community property does not automatically pass to the surviving spouse — it requires a will, a trust, or a CPWROS titling. Without any of these, community property passes through probate.

The most common solution: a revocable living trust that holds community and separate property. Assets in the trust avoid probate, the double step-up still applies at death (the trust does not change the community property character of assets), and the surviving spouse can access all assets immediately.

Portability and the OBBBA $15M exemption

The 2026 federal estate exemption is $15,000,000 per person ($30M for a couple with portability), made permanent by the One Big Beautiful Bill Act in July 2025.³ At this level, federal estate tax affects relatively few couples. But:

• Several community property states have their own estate taxes with much lower exemptions (Oregon, Washington, Minnesota — though not all CP states have state estate taxes)
• The portability election still requires filing a federal estate tax return within 9 months of the first spouse's death, even if the estate is well below the federal threshold
• State-level estate taxes can make trust planning (especially a credit shelter/bypass trust) worthwhile even for couples with estates under the federal limit

Separate property and estate planning

If you have substantial separate property — a pre-marital business, inherited assets — your estate plan needs to distinguish between community and separate property carefully. Upon death, separate property does not receive the double step-up; only the decedent's share steps up (same as common-law rules). Keeping accurate records of which assets are separate vs. community is both a tax issue and an estate administration issue.

Moving between community property and common-law states

Moving FROM a community property state to a common-law state

Assets acquired while you lived in a community property state retain their community character even after you move. For tax purposes, the double step-up under IRC § 1014(b)(6) still applies to assets that were community property when acquired.¹

However, some common-law states do not recognize community property for divorce purposes, which means your assets could be divided under equitable distribution rules rather than 50/50 community property rules if you divorce after moving. California and Washington apply "quasi-community property" rules in their own courts even after a move — but the destination state may not.

Practical steps when moving from a CP state to a common-law state:

1. Document the community property character of assets at the time of the move (written inventory with account statements)
2. Update your estate plan with an attorney in the new state
3. Keep community property assets in separate accounts from post-move separately-earned assets if you want to preserve the double step-up benefit

Moving TO a community property state from a common-law state

Assets you owned before moving remain separate property. Community property treatment starts from the date of your move — only income earned and assets acquired after the move are community property. Your pre-move assets do not automatically convert to community property.

If you want pre-move separately-titled assets to be treated as community property (for example, to get the double step-up benefit), some CP states allow conversion via a written agreement or deed. An estate planning attorney in the new state can document this properly. Without a formal conversion, your pre-move brokerage accounts retain their separate character and only the decedent's half gets a step-up.

Unmarried couples in community property states

Community property rules apply only to married couples. Unmarried cohabitants do not automatically gain community property rights regardless of how long they live together. If one partner dies without a will and without JTWROS titling on accounts, the surviving partner has no automatic claim to jointly managed assets. The estate passes to the deceased's legal heirs.

For unmarried couples in community property states, the planning checklist is the same as anywhere else: beneficiary designations on all retirement accounts and life insurance, JTWROS or TOD titling on brokerage accounts, and a will or trust to direct other assets. The community property double step-up is not available to you, but everything else about careful estate planning still applies. See our financial planning guide for unmarried couples for a complete checklist.

Practical checklist for couples in community property states

When a fee-only advisor makes a difference

Community property planning sits at the intersection of tax law, estate law, and retirement planning. The double step-up decision — whether to hold appreciated assets as community property, convert separate property to community, or structure assets differently — requires running projections specific to your balance sheet: current cost basis, expected appreciation, time horizon, state of residence, and estate size. Getting this right before the first spouse dies is worth far more than trying to reconstruct it afterward.

A fee-only couples advisor can model the after-tax value of the double step-up against other strategies (like Roth conversion or tax-loss harvesting), help structure asset titling correctly, and coordinate with your estate attorney. The planning work is done once and pays dividends for decades.

Sources

1. IRC § 1014(b)(6) — Basis of Property Acquired from a Decedent. Community property: both halves of community property receive a full step-up in basis at the death of the first spouse. Cornell Law School, Legal Information Institute.
2. IRS Publication 555 — Community Property. MFS filing rules in community property states, Form 8958, community vs. separate income splitting, state-by-state rules. Values verified June 2026.
3. IRS — One Big Beautiful Bill Act: Key Tax Provisions. Federal estate and gift tax exemption permanently set at $15,000,000 per person effective 2026; portability preserved.
4. Kitces — The Double Step-Up In Basis For Community Property. Comparison of step-up treatment in CP vs. common-law states; planning strategies around asset titling and basis optimization.
5. Nolo — Community Property States. State-by-state overview, separate vs. community property definitions, commingling rules, and CPWROS availability by state.

Community property laws are state-specific and can change. Consult an estate planning attorney licensed in your state before titling assets or converting property. Federal tax treatment per IRC § 1014(b)(6) and IRS Pub. 555; verified June 2026.