Gross Beta Activity
EPA MCL
4 mrem/year
EPA's health goal of zero for beta and photon radioactivity is set as a dose in millirem per year; this gross beta screening result in pCi/L cannot be compared with it, so it is shown without a verdict.
Health Effects
Increased risk of cancer
Source: EPA — National Primary Drinking Water Regulations (retrieved 2026-07-27)
Common Sources
- Decay of natural and man-made deposits of certain minerals that are radioactive and may emit forms of radiation known as photons and beta radiation
Is your Gross Beta Activity result safe? Get a free reading
The EPA MCL for Gross Beta Activity is 4 mrem/year. Upload your water test (PDF or a photo) and we'll email a plain-English reading of where your result lands — and every other number — free. Educational only, no medical claims.
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Water filters certified under the following NSF standards are effective at removing Gross Beta Activity:
Filter recommendations for this contaminant are being updated.
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About the EPA MCL
This is the enforceable federal limit water systems must meet.
Contaminant Type
Gross Beta Activity is classified as a Radionuclides contaminant.
Related Radionuclides Contaminants
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Find out if Gross Beta Activity is in your tap water.
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