Radon and Affordable Housing: LIHTC, Section 42, and Section 8 in Georgia

1. Why affordable housing is financed differently

A market-rate apartment deal usually runs on one mortgage and one lender. Affordable housing is layered. A typical deal stacks several sources of capital, and the equity often comes from selling tax credits rather than from a single loan. That is the core of the Low-Income Housing Tax Credit program, commonly written as LIHTC and referred to by its Internal Revenue Code home, Section 42. Investors buy the credits, a syndicator packages them, and the property has to keep meeting affordability rules for a long compliance period.

Project-based Section 8 is a different track again. There the federal subsidy is attached to the units through an assistance contract, and the property carries physical-condition and resident-safety obligations tied to that subsidy. The point for an owner is that affordable housing rarely runs through a standard HUD mortgage in the way a Section 232 or MAP loan does. Because the financing is different, the place where radon shows up is different too.

2. Where radon testing comes up in these deals

On an affordable-housing property, radon does not usually arrive through one tidy federal mortgage rule. It comes up through three doors at once. The first is the state allocating agency that awards the tax credits and administers related programs. The second is your equity investor or syndicator, who sets diligence conditions to protect the value of the credits they are buying. The third is the underlying resident-safety and environmental obligations that travel with affordable housing.

Because more than one party can attach a radon condition, the requirements can stack. An investor may ask for testing even where an agency document is silent, or an agency program may call for it as part of the environmental review. Treat radon as a normal line item in your diligence checklist and ask each party what they expect, rather than guessing from a generic template.

3. LIHTC and Section 42: the allocating agency

LIHTC is administered at the state level. Each state has a housing finance or development agency that allocates the credits and publishes a Qualified Allocation Plan describing how it scores and conditions deals. In Georgia, the state agency that administers the tax-credit and HOME programs is where these conditions live. That agency, not a single national handbook, is the body that decides whether and how radon testing is built into a given allocation.

Practically, that means the document trail you should read is the allocating agency's application materials, environmental requirements, and any rehab or new-construction standards it references. Because allocating-agency requirements are set by the program and updated periodically, do not lift a percentage or a testing scope from another state or another year and assume it applies. Confirm the current radon expectation with the agency administering your award. You can learn how testing is coordinated on these properties on our multifamily radon testing page.

4. Project-based Section 8 and resident safety

Project-based Section 8 attaches the subsidy to the units, and with that subsidy come physical-condition and resident-safety obligations. Radon is an indoor air-quality hazard, so it sits naturally inside that resident-safety frame even when it is not spelled out in a single line. On these properties, radon can surface through the environmental review tied to the financing, through the assistance contract and its physical-condition expectations, or through a lender or investor condition layered on top.

The honest framing for an owner is structural rather than prescriptive. Whether a specific Section 8 property must test, and how broadly, depends on how the deal is financed and which program documents govern it. Because those documents change and overlap, verify the current requirement with the administering agency and your lender instead of treating any one standard as universal.

5. What syndicators and investors look for

The equity investor and the syndicator who packages the credits are buying a long-term position in a property that has to perform for years. They protect that position with diligence conditions, and environmental items, radon among them, are a common part of that list. An investor may require a defensible radon report as a closing condition, may want a mitigation plan and budget where elevated results are likely, and may want post-mitigation confirmation that levels were brought down.

The useful instinct here is to surface radon early in negotiations rather than have it appear as a late condition. A clean, protocol-based report removes a question from the investor's checklist, and a known mitigation budget keeps a high reading from becoming a closing surprise. What a given syndicator requires is set by that party, so ask for their environmental scope in writing and build to it.

6. How testing fits the development and rehab timeline

Timing is where owners save or lose money. Radon testing fits most cleanly into the same due-diligence and environmental window as the Phase I site work, before closing and before the construction schedule hardens. On an acquisition-rehab deal, testing during diligence lets you fold any mitigation into the construction scope and budget while the contractor is already mobilized, instead of discovering it after the work is priced and underway.

For new construction, the parallel step is radon-resistant design. Builders often follow third-party standards for radon-resistant features in new multifamily and commercial construction, and an allocating agency or investor may reference those as part of the build standard. Confirm the exact timing and any design expectations your program and investors apply, since those are set by the program rather than by a universal rule. Our guide to HUD radon requirements for multifamily properties walks through how a separate, mortgage-based track handles the same hazard.

7. What property managers carry after closing

Radon does not end at closing. Affordable properties carry long compliance and affordability periods, and the resident-safety obligation runs the whole way through. For the manager, that means keeping the radon record with the rest of the property file: the original report, any mitigation system installed, the post-mitigation confirmation, and a plan for any future testing the property's program or investors expect over the hold.

Where a mitigation system exists, it is a building system like any other and benefits from periodic checks that the fan is running and the manometer reads correctly. Treat radon documentation as part of normal asset management so that a future refinance, resyndication, or agency review finds a clean, current record rather than a gap.

8. Radon risk in metro Atlanta

Georgia does not have a state radon testing law, which leads some owners to assume radon is not a local concern. The data says otherwise. On the EPA Map of Radon Zones, four metro Atlanta counties, Fulton, Cobb, DeKalb, and Gwinnett, are Zone 1, the highest category, meaning a predicted average at or above 4.0 pCi/L. Several surrounding north Georgia counties also carry elevated designations driven by the region's granite and uranium-bearing bedrock.

For an affordable-housing property in metro Atlanta, the combination of program-driven testing expectations and genuinely elevated regional radon means high results are common enough to plan for. Building the testing timeline into your development or rehab process, rather than reacting to it, keeps a high reading from turning into a closing delay or a budget surprise.

9. Frequently asked questions