Lead paint was banned from US homes in 1978, but banning a product didn't remove it. Millions of older houses still carry it under newer coats, harmless right up until somebody sands, scrapes, cuts, or demolishes the surface. That's why the test comes before the tools: a swab costs a few dollars, while disturbing lead paint unknowingly can spread dust through rooms that were safe the day before.
Year built is the first filter. Houses built before 1950 carry the highest odds — lead paint was used heavily and at high concentrations. Homes from 1950 to 1978 still test positive often enough that guessing isn't a plan.
Lead paint was prized where paint took a beating, so it concentrates on high-wear, high-friction surfaces rather than spreading evenly across every wall.
Windows and window trim. The single most common spot. Sashes grinding against frames generate dust even without renovation, and window paint was often the highest-lead paint in the house.
Doors, door frames, and baseboards. Same logic — hard, glossy coatings on surfaces that get bumped and scrubbed.
Exterior siding, porch floors, and railings. Weatherproof paint meant lead, and foot traffic grinds porch coatings into dust that gets tracked inside.
Kitchens, bathrooms, and stair parts. Enamel on cabinets, tub surrounds, banisters, and stair treads. Walls and ceilings are lower on the list — flat wall paint usually carried less lead — but "usually" is why you test instead of assuming.
One wrinkle: the top coat is rarely the original. A negative on the surface says nothing about the layers under it — the same trap that catches people before they paint over wallpaper or strip trim. The oldest layer counts.
| Swab test | Mail-in lab test | Pro XRF inspection | |
|---|---|---|---|
| Cost | About $1–$4 per test | About $25–$45 per sample | Roughly $300–$500 per home |
| Speed | 30 seconds to 2 minutes | About 3–10 business days | Same day, on site |
| Result | Yes or no | Numeric — percent or mg/cm² | Numeric, every surface |
| Best for | One project, a few surfaces | Confirming a swab result, records | Whole-house answers, home sales |
| Watch out for | Missed layers, expired kits | Sampling error — the chip is the test | Cost; overkill for one room |
Swab kits are the right starting point for a single project. Only buy kits the EPA recognizes for consumer use, check the expiration date, and follow the timing exactly — reading a swab too late can produce a result the chemistry no longer supports. Swabs can also miss lead when the chemical can't reach the deepest layer, which is why the cut in step 2 matters.
Lab tests trade speed for certainty. You mail a paint chip, the lab measures it, and you get a number instead of a color change — the result you want when a finding will shape a big renovation budget or documentation for a rental. Dust-wipe lab tests answer a different question: not "is lead in this paint?" but "is lead dust already on this floor?"
Pick your spots from the work plan. List every surface the project will sand, scrape, cut, or remove, and test each one separately — a window sash, its frame, the wall, and the baseboard were painted at different times with different paint.
Score a small wedge through all layers. Cut a shallow V down to bare wood or plaster, about thumbnail size. This exposes every layer so the swab touches the oldest paint, not just the newest coat — the step most DIY tests get wrong.
Run the swab exactly as directed. Rub the exposed wedge firmly for the full time on the package and read the color at the stated moment. Pink or red on common kits means lead detected. Note the result, spot, and date on tape beside it.
Confirm borderline results by mail. A faint color change, an expired kit, or a negative swab on a pre-1950 window all deserve a lab chip. Bag a small sample including every layer, label the location, and keep demo on hold until the result returns.
Clean the test spots. Wipe each cut area and the floor below with a damp disposable cloth, bag the cloth and gloves, and wash your hands. Testing makes a tiny amount of debris — treat it with the same respect as the full job.
A positive test doesn't cancel the project. It changes how the work gets done — wet methods instead of dry scraping, plastic containment, no open-flame burning or high-heat guns, and cleanup by damp wiping and HEPA vacuum rather than a broom. For small, intact areas, painting over lead paint with an encapsulant can be safer than removing it, and the prep looks a lot like careful room painting prep — minus any sanding.
Rentals and sales have their own paperwork: federal law requires sellers and landlords of pre-1978 housing to disclose known lead hazards before signing. A lab report makes that conversation simple, and it's one more reason buyers benefit from the broader checks in a used house inspection checklist.
Testing only the top coat. A clean surface layer over 1940s enamel is the classic false all-clear. Always cut to the substrate.
Testing one window and clearing the house. Rooms were repainted at different times with different products. Results apply to the surface tested, not the building.
Dry sweeping afterward. Cleanup is wet wiping and HEPA vacuuming. A broom puts the dust back in the air.
Treating a negative swab as a legal clearance. Swab tests are screening tools. For a sale, a rental, or a whole-house renovation, a certified inspector's XRF survey is the document that carries weight.
Swabs answer the weekend question — "can I sand this trim?" — for a few dollars. Lab tests answer the planning question with a number. A positive result on a job big enough to hit the RRP thresholds turns the work into a certified pro's job by law, not by preference.
Swab kits run about $10–$25 for a multi-pack — a few dollars per surface. Mail-in lab analysis costs roughly $25–$45 per sample. A certified inspector with an XRF analyzer typically charges $300–$500 per house, with same-day results.
EPA-recognized swab kits are reliable screening tools when used exactly as directed. Their weak spot is depth: if the chemical never touches the oldest layer, a negative can be wrong. Cutting a wedge to bare substrate and confirming doubtful results by lab closes most of that gap.
Often, yes. Intact lead paint covered with regular paint or a purpose-made encapsulant is a recognized management method, and it avoids creating dust. Peeling surfaces and friction spots like window sashes are the exceptions — those keep generating dust under any coating.
Homes built in 1978 or later are considered low risk because residential lead paint was banned that year. "Low risk" isn't "no risk" — salvaged doors, imported fixtures, and old painted furniture brought into a newer house can still carry lead.
For paid work in pre-1978 housing disturbing more than 6 square feet per room indoors or 20 square feet outdoors, yes — EPA RRP rules require a certified firm. Homeowners working on their own home aren't covered by that federal rule, but local laws can be stricter.