Tax Season 2026: The New Documentation Checklist for Medical Mold Deductions

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Financial Briefing January 24, 2026 NMI Research Team

Filing Guide: If you paid for remediation in 2025, you may be eligible to deduct it as a medical expense. Here is the strict paper trail the IRS requires.

Executive Summary
  • The Law: Under IRS Publication 502, mold remediation is deductible only if medically necessary to treat a specific illness.
  • The Trap: You cannot deduct expenses that increase your property value. You must prove the work was a “restore,” not an “upgrade.”
  • The Limit: Deductions apply only to the amount exceeding 7.5% of your Adjusted Gross Income (AGI).

As the 2026 tax filing season opens, many homeowners are unaware that the thousands of dollars they spent on mold removal last year might be partially recoverable. However, the IRS draws a sharp line between “home repairs” (not deductible) and “medical improvements” (deductible).

If the primary reason for the remediation was to alleviate a medical condition—such as asthma, severe allergies, or mold toxicity—you have a valid claim. But you need the paperwork to prove it.

The “Medical Necessity” Requirement

You cannot simply claim the deduction because mold is unhealthy. The IRS requires a direct link between the cost and a diagnosed condition.

Crucial Step: You must have a “Letter of Medical Necessity” from a physician. This letter should be dated before the work commenced, though some auditors accept letters dated immediately after diagnosis. The letter must explicitly state: “The remediation of the patient’s home is medically necessary to treat their chronic respiratory condition.”

The “Capital Expense” Worksheet

This is where most filings fail. The IRS argues that home improvements add value to your asset. You can only deduct the difference between the cost of the work and the increase in home value.

“If you spend $15,000 on remediation and your home value increases by $0, the full $15,000 is a medical expense. If your home value increases by $15,000, your deduction is $0.” — IRS Pub 502

Since pure mold remediation (cleaning and restoring) rarely increases a home’s market value above its pre-damage state, you can typically claim the full amount—provided you document it correctly.

The 2026 Documentation Checklist

Before you send your documents to your CPA, ensure you have this file ready:

Physician’s Statement: Diagnosis code and recommendation for environmental control.
Itemized Invoices: Must separate “Cleaning/Removal” from “Reconstruction.” (Note: Upgrading to granite countertops during the fix is NOT deductible).
Photographic Evidence: Before and after photos of the damage.
Appraisal Statement (Optional): A statement from a real estate professional confirming the repair did not increase the home’s Fair Market Value beyond its original baseline.

Do You Pass the Math Test?

We have created a digital version of the IRS Capital Expense Worksheet. Enter your remediation costs and AGI to see exactly how much you can write off.


Open Deduction Calculator
Financial Disclaimer: The National Mold Index does not provide certified tax advice. This guide is for educational purposes based on IRS Publication 502. Always consult a CPA before filing your return.