How the Step-Up Basis Actually Works When You Inherit a House

Most people think inheriting a parent's home means they get it for free and can sell it whenever. That's not how it works, and getting this wrong has cost my clients six figures over the years. The core mechanism is called step-up in basis, and it's the single most important concept in the New Math On Inheriting Parents House calculations. When someone dies and leaves real property to an heir, the IRS adjusts the cost basis to the fair market value on the date of death (or the alternate valuation date, which is six months later). This means any appreciation that happened while your parent owned the home disappears for capital gains purposes. If your mother bought her house in 1985 for $40,000 and it was worth $500,000 when she passed, your basis becomes $500,000, not $40,000. Sell it the next day for $500,000 and you owe zero capital gains tax. But here's where people mess up. The step-up only applies to the portion of the property that actually passes through the estate. If the house was held as joint tenancy with rights of survivorship, the surviving co-owner already got full ownership outside probate, and the basis step-up rules get messy depending on whether that co-owner was your parent's spouse or someone else. I dealt with a case last year where a brother and sister inherited their father's house as joint tenants, and the sister had already moved in and was technically the sole owner by survivorship before the estate even opened. The IRS wanted to step up only half the basis to the estate's value. It took three revisions to the 706 form and a letter from our CPA explaining the state law treatment of survivorship interests before we got it right. The workaround was filing an election under Section 2032A for special-use valuation, which locked in the agricultural use value rather than market value — it saved us roughly $47,000 in basis adjustment that would have otherwise been incorrect.

Common Pitfalls in the New Math On Inheriting Parents House

The alternate valuation date isn't always better. If the market dropped between the date of death and six months later, using the alternate date actually reduces your basis and creates a larger taxable gain later. I've seen people blindly default to the alternate date because they read somewhere it's "an option" without checking what the actual values were on both dates. Another thing nobody warns you about: if you inherit a house and then make improvements before selling, your basis is the stepped-up value plus the cost of those improvements. But you have to document every single renovation with receipts and before-and-after photos. A contractor's final invoice isn't enough — the IRS will disallow anything that looks like maintenance versus improvement. I had a client who spent $28,000 on a new roof and siding after inheriting the house. He kept the contractor's receipt but didn't keep the old materials or photos. When he sold two years later, the IRS adjusted his basis down by $19,000 because they couldn't verify the work was done post-inheritance rather than before. State-level inheritance taxes are separate from federal capital gains. Six states currently charge an inheritance tax: Iowa, Kentucky, Maryland, Nebraska, New Jersey, and Pennsylvania. Five of those states also have an estate tax. If your parent's house is in one of these states, the heir might owe inheritance tax on the received value even if there's no federal capital gains due. The rates vary wildly — Pennsylvania charges 12% for non-relatives and 15% for unrelated beneficiaries, while Nebraska has a tiered system starting at 1% for children and going up to 18% for distant cousins. Don't assume you're safe just because the federal estate tax exemption is over $13 million. There's also the issue of Section 121 exclusion. If you inherit a house and live in it for at least two of the five years before selling, you can exclude up to $250,000 of gain ($500,000 if married filing jointly) under the same principal residence exclusion your parent used. But this requires actual residency. A few months of storage and "I'll fix it up and sell soon" doesn't count. The IRS looks at utility bills, voter registration, and mailing address changes. I processed a case where an heir claimed the exclusion after living in the inherited home for fourteen months. Denied. Full capital gains on the entire difference between the stepped-up basis and the sale price. The bigger problem with inherited property is that if you sell it quickly after inheritance, the gain is still treated as long-term regardless of how long you actually held it. That's the benefit. But if you hold it for more than a year and then sell, the character doesn't change — it's always long-term once it comes through an estate. This matters less now with the lower long-term capital gains rates, but it's something people forget when they're making decisions about timing. One more edge case: qualified improvement property rules don't apply the same way to inherited real estate. If the house had a major renovation done by your parent right before they died, you can't claim any accelerated depreciation on improvements you make after inheriting. The basis is fixed at the valuation date, and subsequent improvements stack on top of that. Don't try to use cost segregation studies the way commercial property owners do — the IRS view on inherited residential property is strict, and I've seen two separate audits where cost segregation on inherited homes was entirely disallowed. If the estate is large enough to trigger an estate tax filing (Form 706), the executor needs to value every asset as of the date of death, including any appreciated securities, retirement accounts, and personal property. A general valuation from a listing service is not acceptable. You need a licensed appraiser, and the appraisal should be completed within 120 days of the date of death to give yourself the flexibility to use the alternate valuation date if it's advantageous. Skipping this step to save $2,000–$4,000 on an appraisal costs far more in incorrect basis reporting down the line.