Gross Alpha Activity in Drinking Water
EPA limits, health effects, and what to do if your water is affected.
🩨 Health Effects
A measure of total radioactivity from alpha-emitting particles, primarily naturally occurring radionuclides like radium-226 and thorium. Long-term exposure above 15 pCi/L increases cancer risk.
📍 Sources in Water
Alpha radiation in groundwater comes from naturally occurring radioactive materials in rock and soil, mainly radium, uranium, and thorium. Found most often in areas with granite or uranium-bearing rock.
✅ What To Do
Reverse osmosis and distillation can reduce gross alpha activity. Ask your utility which specific radionuclides are elevated. Additional testing is usually required to identify the specific radioactive compounds.
Check your tap water for Gross Alpha Activity
Search your ZIP code to see if your water system has had Gross Alpha Activity violations, plus lead testing results and an overall safety grade.
Search your ZIP code →Data from the EPA's Safe Drinking Water Information System (SDWIS). MCLs reflect minimum federal standards; some contaminants may pose health risks below these thresholds.