The useful question isn’t whether a kit is accurate — it’s whether it measures the thing you’re worried about, in the place that thing shows up. Free path first, then the paid kit, then what a result should and shouldn’t tell you.
Not sure where to start?
Your address decides which test comes first
Radon, water contaminants, and lead paint cluster by geography, water source, and build year.
Charcoal canister, alpha track, and electret devices are EPA's own recommended short-term test types; the analyte (radon gas) is unambiguous, the test is inexpensive, and a result at or above the 4 pCi/L action level maps directly to an established fix (sub-slab depressurization) — validated and actionable, the same tier as blood lead testing.
Free path first
Many state radon programs and local health departments distribute free or discounted short-term test kits — EPA directs homeowners to their state radon office to check availability before buying one.
Detects: lead, PFAS (PFOA/PFOS and related compounds), arsenic
Certified-lab mail-in analysis against EPA reference methods, not a consumer test strip — results are legally defensible and lab-verified.
Free path first
Utility Consumer Confidence Report (free, annual) plus direct request to your water utility — coverage and free testing vary by utility and don't capture your home's own plumbing.
What the number means: Lead action level 15 ppb (headed to 10 ppb, compliance ~2027); PFOA/PFOS MCL 4.0 ppt each (current); arsenic MCL 10 ppb (public systems only). — U.S. Environmental Protection Agency
Environmental, actionable test with a published EPA clearance standard and a defined remediation response (HEPA vacuum + wet cleaning, or professional abatement). NLLAP-accredited lab analysis of a wipe is EPA/HUD's validated method for dust; unlike instant colorimetric kits, which EPA has only recognized for painted surfaces, not dust.
What the number means: EPA dust-lead clearance/action levels (in force since Jan 2026): floors ≤5 µg/ft², window sills ≤40 µg/ft², window troughs ≤100 µg/ft²; any lab-reportable amount otherwise counts as identifying lead dust present. — U.S. Environmental Protection Agency
FDA itself recommends instant swabs as a practical screen for pottery a consumer can't otherwise verify, so there's real, agency-acknowledged utility here — but it is not FDA's own test. FDA's leachable-lead action levels are set by a 24-hour acid-extraction lab method (ASTM C738), not a surface swab, and CPSC's own evaluations of the same rhodizonate chemistry found concrete failure modes: false negatives when lead sits under an intact glaze/topcoat, and false positives on red-toned surfaces from color interference — which happens to be the exact decorative color range FDA flags as highest-risk. A pass isn't lab clearance and a fail isn't a quantified hazard, which is a tier-2 profile (useful with real, documented conditions and limits), not tier-1 (validated equivalent to the standard) or tier-3 (do not recommend).
What the number means: FDA CPG 545.450 sets leachable-lead action levels of 3.0 µg/mL (flatware, avg. of 6 units), 2.0 µg/mL (small hollowware), 1.0 µg/mL (large hollowware), and 0.5 µg/mL (cups, mugs, pitchers — any one of 6 units), measured by a 24-hour acid-extraction lab test (ASTM C738), not a swab. — U.S. Food and Drug Administration
Genuinely useful as a trend tool for spotting VOC/PM2.5 spikes after new furniture, paint, flooring, or heavy candle/air-freshener use, and for checking whether ventilation habits are working. Not tier 1 because there is no single validated action threshold to score a reading against — EPA has no federally enforceable indoor VOC standard and states it has no authority to regulate household products or indoor air quality generally. EPA's own guidance on these devices also flags real accuracy/precision limitations, sensitivity to placement/temperature/humidity, degrading reliability over device lifespan, and explicitly notes their alerts are not designed to warn of danger the way a CO or smoke alarm is. Not tier 3 because the readings are not meaningless — they're a legitimate relative signal, just not a pass/fail safety test.
Free path first
Source control (choosing lower-VOC products, airing out new furniture/flooring before use) and increased ventilation (open windows, run exhaust fans) are EPA's first-line recommendations for reducing indoor VOCs, ahead of any device — both cost nothing.
Detects: lead (qualitative, presence/absence above ~0.5% by weight / 5,000 ppm)
EPA-recognized under the RRP Rule (40 CFR 745), but only on the negative-response criterion (≤5% false negative at 95% confidence) — no kit has met the separate false-positive criterion, so a positive result carries a less formally-bounded reliability figure than a negative one. Recognition also only covers painted wood, drywall, plaster, and ferrous metal (not stucco or non-ferrous metal), and each swab covers just 1-2 sq in, so a single test can miss lead sitting in an underlying paint layer the swab didn't reach. Real enough conditions to place this at 'defensible with conditions' rather than clean tier-1, even though it remains a legitimate, actively-recognized screening tool for its specific covered use case.
Free path first
HUD-funded local lead hazard control grantee programs (via county/state health departments) provide free lead testing and hazard reduction for eligible lower-income households in pre-1978 housing — availability and eligibility vary by location, so check locally before buying a kit.
What the number means: EPA's negative-response criterion for recognized kits: reliably rules out lead at or above 1.0 mg/cm² (0.5% by weight) on painted wood, drywall, plaster, or ferrous metal — no recognized kit meets the separate false-positive criterion. — U.S. Environmental Protection Agency
Tier 1Validated and actionable — a recognized method with a published threshold to act on.
Tier 2Defensible with conditions — useful if you know exactly what it does and doesn't detect.
Tier 3Not recommended — never publishes as a recommendation on this site.
The free alternative is always named before any paid option — naming the free path is what makes a paid recommendation credible.
Health screening
Coming soon
Everything above tests a house. The other half of the picture is whether the people in it are current on the screenings their doctor would actually recommend — which is a different question, answered by different tools, and one we’d rather build properly than quickly. It’s coming, because health is most of what safety means.
