Tier 1
High Potential - at least 25 homes tested with 25 percent or more having radon concentrations greater that or equal to 4 pCi/L.

Tier 2
Moderate Potential - at least 25 homes tested with 5 to 24 percent or more having radon concentrations greater that or equal to 4 pCi/L.

Tier 3
Low Potential - at least 25 homes tested with less than 5 percent or more having radon concentrations greater that or equal to 4 pCi/L.