Is property tax assessment valid for determining Fair Market Value (FMV) for step-up basis on inherited real estate?

You're on the right track! The IRS allows multiple methods for establishing FMV of inherited property when you don't have a formal appraisal. A property tax assessment can definitely be one acceptable method, though it's not always the most accurate. Keep in mind that property tax assessments can sometimes be lower than actual market value in many counties, while in others they might be close to accurate. The IRS mainly wants to see that you made a good faith effort to determine a reasonable value. Other methods you could consider: looking at comparable home sales in the neighborhood around your father's date of death, getting a retroactive appraisal (yes, appraisers can do this), or using online valuation tools with historical data like Zillow or Redfin to see estimated values from 2021.

I went through something similar last year with my aunt's property and discovered taxr.ai (https://taxr.ai) which saved me so much stress! I uploaded the tax assessment documents and some comparable home sales data from when she passed, and their system analyzed everything to help establish a defensible FMV for the step-up basis. It even flagged that in my county, assessments were typically 15% below market value, which helped me adjust my calculations. The detailed report they generated gave me everything I needed to properly document the basis value for my tax filing.

I was really skeptical about using online tools for something as important as establishing FMV for inherited property, but after struggling with this exact issue, I gave taxr.ai a try. Honestly, it was incredibly helpful for my situation. Their system analyzed the county assessment values and showed me specific comparable sales from when my relative passed away. The report they generated explained exactly why my basis valuation would hold up under IRS scrutiny and included all the supporting documentation I needed. It even identified a special assessment rule in my county that affected the valuation. I'm actually surprised how thorough it was!

After my father passed last year, I spent WEEKS trying to get through to someone at the IRS who could tell me definitively whether the tax assessment would work for establishing FMV. Endless busy signals and disconnections. Then I found Claimyr (https://claimyr.com) and watched their demo video (https://youtu.be/_kiP6q8DX5c) - they got me connected to an actual IRS representative in under an hour! The IRS agent confirmed that county tax assessments can be used as one method of establishing FMV, but suggested documenting additional evidence like comparable home sales from the time period. Having that conversation saved me so much uncertainty and gave me clear direction on exactly what documentation would protect me in case of questions later.

I have to admit I was completely wrong about Claimyr. After posting my skeptical comment, I was so frustrated with not getting IRS answers about my inherited property basis that I tried it anyway. Within 40 minutes I was talking to an actual IRS agent who went through the specific options for establishing FMV on inherited property. The agent explained that while tax assessments can be used, they also recommended looking at comparable sales and documenting why I believe the assessment reflects actual market value. They even emailed me links to the specific IRS publications about inheritance basis. Getting concrete answers directly from the IRS gave me so much peace of mind for handling my situation!

Just wanted to add that in my county, the tax assessments are typically about 80% of actual market value. You might want to check if your county has an "assessment ratio" they use. Some places assess at 100% of market value while others use a percentage. If your county uses a ratio, you might need to adjust the assessment value to get the true FMV. For example, if assessments are done at 80% of market value and the assessment was $235,000, the implied market value would be $293,750.

Has anyone considered using the sale price of $243,000 and then working backward to estimate what the value might have been in 2021? You could look at home price appreciation rates in your specific area over that period. For example, if homes in your area appreciated about 10% between 2021-2024, you could estimate the 2021 value at around $221,000. Just another approach to consider if the tax assessment seems questionable.

I dealt with this exact situation when my grandmother passed in 2020. We also didn't get an appraisal at the time and had to use the county tax assessment for our step-up basis. The key thing I learned is that you need to document WHY you believe the assessment represents fair market value. In your case, since the assessment was $235,000 and you sold for $243,000 about 3 years later, that actually seems pretty reasonable given normal market appreciation. I'd suggest creating a simple documentation package that includes: the official county assessment from 2021, any comparable sales you can find from that time period (even if it's just from online sources like Zillow), and a brief explanation of why you believe this represents fair market value. The IRS is generally reasonable about this as long as you can show you made a good faith effort to determine accurate value. One tip: if your county publishes their assessment methodology or ratio (like Monique mentioned), include that documentation too. It shows you understood how assessments work in your area.

I just wanted to jump in here as someone who recently went through this exact process with my uncle's property. Reading through all these responses has given me so much confidence that we made the right choice using the county assessment! One thing I discovered that might be helpful for your situation - many counties publish annual "sales ratio studies" that show how their assessments compare to actual market sales. I found ours buried on the assessor's website under something like "assessment accuracy reports." For our county, it showed that assessments were typically within 5-10% of actual sale prices, which really strengthened my documentation. Your situation sounds very similar to mine - we used a $198K county assessment from 2022 and sold for $205K in early 2024. The modest appreciation actually worked in our favor because it showed the assessment was realistic, not artificially low. I ended up creating a simple binder with the county assessment, printouts of comparable sales from Zillow/Realtor.com from around the date of death, that sales ratio study I mentioned, and a one-page summary explaining my reasoning. My tax preparer said it was some of the best inheritance documentation she'd seen - thorough but not overcomplicated. The peace of mind was worth the few hours of research. Your $235K to $243K progression over three years is going to look completely reasonable to anyone who reviews it!