Lead Dust Wipe Test Kits: What the Clearance Numbers Actually Mean

The short answer

A lead dust wipe test kit works like this: you wipe a defined area of a floor or window sill with a moist wipe, using a specific technique, then mail that wipe to an accredited laboratory. The lab digests the sample and reports a result in micrograms of lead per square foot (µg/ft²).

That's a different test from the instant paint-chip swabs sold at hardware stores (LeadCheck, D-Lead and similar), which react to lead with a color change you read on the spot — that's a separate SafeMama page. EPA's recognition program for those instant kits covers painted surfaces, not dust; the agency has not validated them for reading a lead level in settled dust, and independent studies of spot-test kits used on dust have flagged real accuracy limitations under normal household conditions. For dust specifically, a lab-analyzed wipe sent to a laboratory accredited under EPA's National Lead Laboratory Accreditation Program (NLLAP) is the validated method.

The reason dust gets tested separately from paint at all: a child's actual exposure route is hand-to-mouth contact with dust on floors and sills, not the paint itself. A wipe test measures the thing a child is actually touching.

What the clearance standards actually mean

EPA revised these numbers twice in recent years, and the current figures are lower than what still circulates in a lot of older articles.

There are two different standards, and they answer two different questions:

The dust-lead reportable level — "is there lead here at all." Under EPA's final rule from November 2024 (effective January 2025, with full compliance for the standard itself as of January 12, 2026), the numeric hazard standard was replaced with any reportable level as analyzed by an NLLAP-recognized laboratory — meaning any amount the lab can quantify and report now counts as identifying lead dust in the sample. This replaced the prior numeric standard set in a January 2021 rule (10 µg/ft² for floors, 100 µg/ft² for window sills), which itself had replaced the original 2001 figures (40 µg/ft² and 250 µg/ft²).

The dust-lead action level, or post-abatement clearance level — "is it safe to reoccupy after work was done." As of the same rule, this is:

• Floors: 5 µg/ft²
• Window sills: 40 µg/ft²
• Window troughs: 100 µg/ft²

These are all lower than the 2021 figures they replaced (10 / 100 / 400 µg/ft²).

One distinction worth being precise about: "clearance" in the technical sense refers specifically to results collected by a certified risk assessor or sampling technician after abatement, renovation, or interim-control work, used to determine a unit can be reoccupied. A homeowner running a mail-in kit on an as-is home, with no remediation underway, is being compared against the same lab-reporting standard, but the result isn't a formal regulatory "clearance" unless it was collected as part of that documented process.

How to do it right

EPA and HUD's wipe-sampling guidance is specific, and following it is what makes a result comparable to the standards above:

• Use a moist wipe meeting the ASTM E1792 material specification (most mail-in kits supply the correct wipe).
• Define the area before wiping. For floors, the standard sample area is about 1 square foot. For window sills and troughs — narrower surfaces — the minimum is 0.1 square foot (roughly 4×4 inches), using tape to mark the boundary rather than a rigid template.
• Wipe in a specific pattern: side-to-side, then fold the wipe and go top-to-bottom, then a third pass around the perimeter — attempting to pick up all visible dust without crossing outside the marked area.
• Use a fresh glove per sample, and package each wipe in the sealed container the lab provides.
• Send it to a lab currently listed under NLLAP — accreditation should be checked at the time of testing, not assumed from a kit's packaging, since lab status can lapse. Results should come back reported in µg/ft², already calculated against the area you measured.

Cost, and any free option

Commercial mail-in kits with lab analysis typically run in the $30–$60 range for a single sample — checking current listings in September 2026, a Pro-Lab kit runs about $11 plus a $30 per-sample lab fee, and pricier lab-fee-only options exist — more for a multi-sample kit covering several rooms.

We could not verify a specific, generally-available free path to a lab-analyzed dust wipe nationally — free testing programs in this space vary a lot by state and county. What we can say with confidence: many state and county Childhood Lead Poisoning Prevention Programs offer free or reduced-cost home lead risk assessments for households with young children, particularly if a child's blood lead test has already come back elevated — but whether that assessment specifically includes a lab-analyzed dust wipe (versus a visual inspection or paint testing) varies by program. Check with your local health department, or call the National Lead Information Center at 1-800-424-LEAD, to ask what your specific program covers before assuming either way.

What SafeMama recommends

If a dust wipe result comes back at or above the action level, the standard response — the one EPA and HUD guidance point to — is a HEPA vacuum plus wet-cleaning protocol: HEPA-filtered vacuuming of floors and surfaces, followed by wet wiping with a lead-specific or high-phosphate detergent, repeated regularly rather than as a one-time clean. That's an interim control, not a substitute for addressing deteriorating lead paint if that's the actual source — a certified risk assessor is the right next call if paint condition looks like the problem.

Be clear-eyed about what one dust wipe test does and doesn't tell you. It's a snapshot of dust loading on one specific surface, on one specific day — not a comprehensive assessment of your home's lead-paint condition, not a soil or water reading, and not a measure of whether a child has already been exposed. That last question is a different test entirely: a blood lead test, which is frequently free through a county health department and is the validated way to answer "has my child been exposed," as opposed to "does my house currently have lead dust."