Gross Alpha Particle Activity
radionuclide
Erosion of natural deposits of certain radioactive minerals.
EPA regulatory status
Legal limit (MCL)
15 pCi/L
Goal (MCLG)
0 pCi/L
MCL 15 pCi/L (excluding radon and uranium). MCLG = 0.
Health effects
Long-term exposure to alpha-emitting radionuclides is associated with an increased risk of cancer.
This is general public-health information, not medical advice — consult your physician with any health concerns.
National violations
63,906
EPA's enforcement data (SDWIS/ECHO) records 63,906 violations of Gross Alpha Particle Activity's rule nationally.
How to remove Gross Alpha Particle Activity
distillation
NSF/ANSI 62
Frequently asked questions
What is Gross Alpha Particle Activity?
Gross Alpha Particle Activity is a radionuclide regulated in US drinking water. Erosion of natural deposits of certain radioactive minerals.
What is the legal limit for Gross Alpha Particle Activity in drinking water?
MCL 15 pCi/L (excluding radon and uranium). MCLG = 0.
What health effects does Gross Alpha Particle Activity have?
Long-term exposure to alpha-emitting radionuclides is associated with an increased risk of cancer.
How many violations of Gross Alpha Particle Activity limits are on record nationally?
EPA's enforcement data (SDWIS/ECHO) records 63,906 violations of Gross Alpha Particle Activity's rule nationally.
How do I remove Gross Alpha Particle Activity from my water?
Filter technologies certified to reduce Gross Alpha Particle Activity include: reverse osmosis (NSF/ANSI 58), distillation (NSF/ANSI 62). Look for a filter independently certified against the specific NSF/ANSI standard for this contaminant — general "reduces contaminants" marketing claims are not the same as a contaminant-specific certification.
Source: EPA National Primary Drinking Water Regulations · Data as of 2026-07-16