Radon Testing Companies

Directory of US radon testers and mitigators with current state or NRPP/NRSB credentials, plus Canadian C-NRPP listings. No paid or sponsored listings. Radon Testing Companies is an independent directory of people and firms with a current radon testing or mitigation credential. US listings come from official state credential files, or from current NRPP or NRSB certifications where a state has no public roster on the site; Canadian listings use C-NRPP credentials. Each listing shows the credential number, issuing body, last-verified date and a link to the official source, and the roster is rebuilt monthly. Search by US ZIP or browse 6,341 US listings across all 50 states and DC, plus 510 Canadian credentials. No listing is paid, sponsored or advertised, and there is no way to buy placement. It also publishes homeowner guides and a state-by-state table of who credentials radon work.