Chapter 04 — The Maryland file

Radon testing & mitigation in Maryland

This site imports no Maryland state roster, so these are current NRPP and NRSB certifications from those programs’ public finders. A national certification is not a state license. We group people by the city on that file. We do not invent neighborhoods. Source: NRPP.

Latest credential check September 14, 2026. Methodology Individual record dates may be earlier.

149current listings

125testing

25mitigation

Fig. 4 — 147 of 149 current listings are mapped. 2 records have an in-state place but no verified city or county coordinate. Each pin is a current listing at the Census city or county centroid on the file, approximate. Pins that share a place are spread so you can click them. Not street addresses.

§ 4.1

Cities with listings

A city appears only when at least one current listing serves it.

§ 4.3

How to verify a radon credential in Maryland

We have not confirmed whether Maryland requires a state radon credential. Treat this as unknown, not as "none required", and ask the Maryland radon program. Listings here are current NRPP or NRSB certifications, which are national and are not a state license.

NRPP finder · NRSB finder · EPA guidance · All fifty states · reviewed September 8, 2026

§ 4.4

Questions about radon credentials in Maryland

Does Maryland license radon testers and mitigators?

We have not confirmed whether Maryland requires a state radon credential. That means unknown, not that none is required. We do not guess at state law, so this site publishes no answer it has not checked. Ask the Maryland radon program.

How do I verify a radon credential in Maryland?

The 149 listings shown here are current NRPP or NRSB certifications, verifiable on those programs' public finders. The latest record check was September 14, 2026; check each listing for its own date. If Maryland also requires a state credential, ask the provider for it and check it with the state agency.

Is an NRPP or NRSB certification enough in Maryland?

We cannot say for Maryland, because we have not confirmed whether the state requires its own credential. A national certification is never a state license anywhere. Treat NRPP or NRSB as evidence of training, then ask the state radon program what else is required.