1 credentialed Iowa radon professional serving Washington, sourced from the Iowa HHS credential rosters and cross-checked against each company's own site. Filter by what you actually need — a mitigation install, a test, or both.
Credential check: every Washington-based contractor below is on an Iowa HHS radon roster (number and roster date on each card). That means they're allowed to do the work, not that they do it well. Check an Iowa license yourself →
Yes. Iowa HHS certifies radon testers (measurement specialists, numbers starting RNTST) and credentials installers (mitigation specialists, numbers starting RNMIT). Mitigation rules in effect since July 1, 2026 require national ANSI/AARST installation standards and a level below 4 pCi/L after the system is installed.