Natural radon reduction rate of the community groundwater system in South Korea

Tank waters from 13 Community Groundwater Systems (CGS) showed average radon reduction rate of 26.5% (varying from −17.9% to 63.3%). When applying the reduction rate of 26.5% to the nationwide CGS, the percentage of CGS having radon level above 100Bq/L decreases from 28.8% to 22.0%. The natural radon reduction method would be applied to the CGS having radon level slightly exceeding guideline of WHO, as an alternative for aeration or GAC. •We measured radon contents of groundwater and tank water from 13 villages in Korea.•The natural reduction rates of radon range from -17.9% to 63.3% (average of 26.5%).•When applying the average natural reduction rate of 26.5% to the nationwide CGS.•Percentage of CGS having radon level above 100 Bq/L decreases from 28.8% to 22.0%.