Radon Pros in Connecticut

Last updated: March 2026

Connecticut has significant radon risk driven by the Reading Prong geological formation that runs through the western and central portions of the state. Much of Connecticut is classified as EPA Zone 1, the highest risk category, with granite and metamorphic bedrock producing some of the highest indoor radon levels in New England. The Danbury, New Milford, and Litchfield County areas are particularly affected. Connecticut requires radon mitigators to be certified through NRPP or NRSB, with the Department of Public Health overseeing radon programs and maintaining a registry of certified professionals. Connecticut is one of the few states that requires sellers to disclose known radon test results to buyers, making radon awareness relatively high in the state's real estate market. Testing is common practice in most Connecticut transactions, particularly in Fairfield and Litchfield counties. Connecticut's radon profile is noteworthy because the Reading Prong affects such a large proportion of the state's land area — unlike larger states where risk is regional, most Connecticut homeowners live within or near Zone 1 areas. The combination of strong regulation, disclosure requirements, and genuine geological risk makes Connecticut one of the better-regulated radon markets in the country. The EPA recommends all Connecticut homes be tested regardless of location within the state.