Radon rules for new homes in Worcester County
The rule
Massachusetts adopted the International Residential Code's Appendix F into its building code. Worcester County is one of three counties, with Essex and Middlesex, listed there as high radon potential (Zone 1) counties. Since 2015, new one- and two-family homes and townhouses there have had to include a passive radon system when they're built. The state health department's radon page puts the start at homes built after January 2, 2015.
What "passive" means
A passive system is built into the house without a fan. The state allows builders to follow either Appendix F or the ANSI/AARST standard for installing it.
Builders don't have to test
The rule requires the system, not a test. The state's advice for anyone buying a newer home is to test before purchase anyway, and to hire a certified mitigation specialist if the result is 4 pCi/L or higher.
Older homes
Homes built before the rule have no required system. Testing is the only way to know.