The Core Rule: Each Spouse Owns Half
Under Idaho Code § 32-906, all property acquired by either spouse during marriage while domiciled in Idaho is community property — unless it falls into one of the separate property categories. Each spouse owns an undivided one-half interest in community property.
When one spouse dies, their half of the community property passes through their estate (by will or intestacy). The surviving spouse's half was always theirs — it does not pass through probate. Only the decedent's half needs to be administered.
This is fundamentally different from common-law states, where a surviving spouse may need probate to claim assets held in the deceased spouse's name alone — even if both spouses always considered them jointly owned.
Community Property vs. Separate Property
| Type | What It Is | Example |
|---|---|---|
| Community Property | All property acquired during marriage while domiciled in Idaho (wages, purchases, retirement contributions) | Home bought during marriage, 401(k) contributions made during marriage, salary deposited into joint account |
| Separate Property | Property owned before marriage | House owned outright before the wedding |
| Separate Property | Property acquired during marriage by gift or inheritance | Inheritance received from a parent, a gift of money from a relative |
| Separate Property | Property designated as separate in a valid written agreement between spouses | Premarital agreement or transmutation agreement signed by both spouses |
| Commingled Property | Community and separate property mixed together | Separate property inheritance deposited into a joint account used for household expenses — may become community property if not kept separate |
What Goes Through Probate — and What Doesn't
| Asset Type | Probate Required? |
|---|---|
| Decedent's ½ of community property (personal) | Yes — passes through estate |
| Decedent's ½ of community real estate | Yes — PR deed required to transfer |
| Surviving spouse's ½ of community property | No — already belongs to survivor |
| Decedent's separate property | Yes — passes through estate |
| Joint tenancy with right of survivorship | No — passes to survivor by operation of law |
| Beneficiary-designated accounts (IRA, 401k, life insurance) | No — passes to named beneficiary |
| Living trust assets | No — governed by the trust |
| Community Property Agreement assets | No — passes to survivor per agreement |
The Community Property Agreement
Idaho spouses can enter into a Community Property Agreement (Idaho Code § 15-6-201 et seq.) that causes all of their community property to pass automatically to the surviving spouse upon the first death — bypassing probate entirely for community property. This is separate from a will and does not require court involvement when the first spouse dies.
A Community Property Agreement must be in writing and signed by both spouses. If a couple executed such an agreement during their lifetimes, review it carefully: all community property covered by the agreement passes automatically to the survivor. Only separate property and any assets excluded from the agreement would go through the estate.
How Community Property Affects the Inventory
When preparing the estate inventory, clearly categorize each asset:
- Community property: List the decedent's one-half value only. The other half is the surviving spouse's and is not a probate asset.
- Separate property: List 100% of the value.
- Commingled assets: Trace the community vs. separate portions if possible, or consult a CPA or attorney.
This categorization also determines the small estate affidavit threshold. If the decedent's one-half share of community personal property (plus any separate personal property) does not exceed $100,000, the small estate affidavit procedure may be available even if the total estate is substantially larger.
The Tax Advantage of Community Property: Full Step-Up in Basis
One of the most significant benefits of community property is the tax treatment at death. In a community property state like Idaho, both halves of community property receive a stepped-up basis to fair market value at the date of the first spouse's death.
In a common-law state, only the deceased spouse's half gets the step-up. The surviving spouse's half keeps its original cost basis.
This full step-up in basis applies to all community property assets — not just real estate. It can mean tens of thousands of dollars in tax savings when beneficiaries later sell inherited assets. It is one of the most significant financial advantages of Idaho's community property system.
Commingling: When Community and Separate Property Mix
Commingling occurs when community property and separate property are mixed together in a way that makes it difficult — or impossible — to trace which portion is which. Idaho courts generally resolve commingling disputes by treating the mixed asset as community property unless the separate property component can be clearly traced.
Common commingling situations:
- Depositing a pre-marital inheritance into the family checking account used for household expenses
- Using separate property funds to improve community real estate
- Contributing separate property to a retirement account that also receives community property contributions
If significant separate property may have become commingled, consult a CPA or Idaho family law attorney before finalizing the estate inventory. Mischaracterizing community property as separate property (or vice versa) can expose the Personal Representative to liability.
More Idaho Probate Guides
- Idaho Small Estate Affidavit: Collect Assets Without Probate
- Idaho Probate Timeline: Key Deadlines for Personal Representatives
Ready to File Idaho Probate Yourself?
Our Idaho guide includes a community property worksheet, inventory templates, and step-by-step instructions for every stage of informal probate — with plain-English explanations of community vs. separate property rules.
Get Your Idaho Guide for $37.99 →One-time payment · Every future state added free · Access from any device