New Radon Testing Rules: What’s Changed?

As of July 24, 2023, Fannie Mae and Freddie Mac have implemented updated radon testing requirements for all Enterprise-backed multifamily properties. These changes are designed to enhance resident safety, ensure environmental compliance, and streamline data collection at a national level.

Whether you’re a property owner, manager, or lender, understanding these updates is crucial for remaining in compliance and protecting tenant health.

What’s New?

1. Expanded Testing Scope

Radon testing requirements have increased significantly:

• 25% of ground-contact units must now be tested (up from 10%), with at least one unit per building.

• Some property types and loan products may qualify for exemptions or deferrals.

2. Certified Oversight is Required

All testing must be overseen by a qualified Environmental Professional (EP):

• EPs or designated representatives must also provide tenant notification in advance.

• Testing must follow federal, state, and local laws, whichever is stricter.

3. Enhanced Data Efforts

The Enterprises are now partnering with the Centers for Disease Control and Prevention (CDC) to standardize and improve data collection surrounding radon in multifamily housing.

4. Ongoing Policy Monitoring

The Federal Housing Finance Agency (FHFA) and the Enterprises will reassess these policies in 2025, evaluating:

• Industry readiness

• Resident impact

• Mission alignment with health and housing goals

Frequently Asked Questions

Q: Is testing required for all loans?
A: Yes—unless the property qualifies for an exemption (e.g., already mitigated, no ground-contact units, or radon-resistant construction).

Q: Do upper-floor units need testing?
A: Not unless required by local/state law.

Q: Can owners perform testing themselves?
A: No. Testing must be overseen by a certified Environmental Professional.

What happens if radon exceeds 4.0 pCi/L?
Two options:

• Retest 25% of units (including those with elevated results), or

• Install a radon mitigation system in all affected areas.

What about special property types?
For detached homes, townhomes, and small multifamily buildings, a representative sample must still be tested under EP supervision.

Testing & Mitigation Done Right

All mitigation must be completed by a qualified radon mitigation professional, and post-mitigation testing is required to confirm safe radon levels.

Although ongoing testing after closing isn’t mandatory, a customized Operations & Maintenance (O&M) Plan may outline future needs, depending on the property and loan type.

Need Radon Testing for Your Multifamily

Property?

At Vert Environmental, we provide certified radon testing services across California. Our team of licensed Environmental Professionals ensures that your property remains fully compliant with all updated Fannie Mae and Freddie Mac requirements.

Whether you’re in Los Angeles, the Bay Area, or beyond—we’re here to make testing simple, professional, and reliable.

Contact Us Today!