Does Your Address Change What's Worth Testing? Radon, Water & Lead Risk by Location

The short answer

Some of this really is about where you live. Radon seeps up from soil and bedrock, so it clusters by geology. Tap-water contaminants track your water source — a private well, a municipal system, or proximity to a known industrial site. Lead paint risk tracks almost entirely to one fact: whether your home was built before 1978, when the Consumer Product Safety Commission's ban on lead-containing paint in residential use took effect.

None of that means an address can tell you your own number. It can only tell you which tests are worth prioritizing first.

What actually varies by location

Radon: geology and soil, at a county-to-county scale. EPA maintains a Map of Radon Zones, built from indoor radon measurements, geology, aerial radioactivity, soil parameters, and foundation types, that assigns every U.S. county to a predicted radon-potential zone. That map is real, EPA-built data — but EPA's own page for it is direct about what it's for: helping "national, state and local organizations target their resources," not telling an individual household whether to test.

Water: your source, not just your city. Whether tap water is a risk depends on which of three different things is true for your specific address — plumbing age (lead is almost always a plumbing problem inside the house, not the source water), proximity to an industrial, airport, or military site that used PFAS-containing firefighting foam, or whether the water comes from a private well at all (federal arsenic and lead rules only govern public water systems; wells aren't covered, and testing them is entirely the homeowner's responsibility).

Lead paint: the year the house was built. CPSC's ban on lead-containing paint for residential use took effect in 1978. A home built after that year is a very different starting risk than one built before it — construction year is closer to a hard cutoff than anything else on this page.

What doesn't — the caution worth taking seriously

EPA's own Map of Radon Zones page states this plainly: "The Map of Radon Zones should not be used to determine if individual homes need to be tested. No matter where you live, test your home for radon." Two houses on the same street, built the same year, can have meaningfully different radon levels because the gas moves through cracks, gaps, and foundation types that vary house to house, not just region to region.

The same logic holds for water and lead, just for different reasons. A water utility's system-wide report reflects the water leaving the treatment plant, not what's happened to it by the time it reaches a specific home's fixtures. A pre-1978 build date raises the odds of lead paint being present; it doesn't confirm it, and plenty of pre-1978 homes have already had it removed or covered.

Location narrows down which test is worth doing first. It never substitutes for doing the test.

What SafeMama recommends

Use where you live to prioritize, not to skip a step. If you're in a higher radon-potential area, that's a reason to test sooner, not a reason to assume the number — order the kit either way. If your home predates 1986 plumbing standards or 1978's paint ban, that's a reason those two tests outrank a PFAS panel unless you're also near a known contamination source. A private well means arsenic testing is entirely on you, since no federal program checks it for you the way it does for municipal systems.

If you want a single starting picture of an address's radon, water-system, and construction-era signals before deciding which test to order first, that's what the tool below is for — it's a prioritization aid, not a substitute for any of the tests linked above.