Contaminant

Uranium in drinking water

Also listed as U

A naturally radioactive metal found in some groundwater. Long-term exposure is a kidney toxin as well as a radiation risk.

This page can’t tell you what’s in your tap water.

Only a test of water from your own tap can. Public-system results describe the system, not your home.

3 sources

01Check your water systemWater Check · system results, not your tap 02Test your tapHow to get a reliable result 03Treatment approachesWhat can reduce it at the tap

On this page · 8 sections

01Reference values
02Is it in my water?
03Testing
04Water filters
05Evidence
06Next steps
07Ask about uranium
08References

Reference values

A legal limit — and a lower health goal.

Each value says what kind of reference it is, and they mean different things. A lower or missing number never means water is safe.

Enforceable limit · MCLFederal · public water systems

30 ppb

The highest level allowed in water a public system delivers. A legal limit, not a health goal.

Applies to: Water delivered by public water systems, not private wells
Status: In force
Source: EPA NPDWR MCL (30 µg/L) · 40 CFR §141.66

Health-based goal · MCLGFederal · not enforceable

0 ppb

The level below which no known health risk is expected. A goal, not a limit.

Applies to: Set alongside the rule as a public-health goal
Status: Published goal
Source: EPA National Primary Drinking Water Regulations — MCLG zero · 40 CFR §141.51

State limit · MCLCalifornia state limit

20 pCi/L

An enforceable limit for public water systems in that state.

Applies to: Public water systems in that state, not private wells
Status: In force
Source: California state MCL (20 pCi/L) · 22 CCR §64443 (Table 64443-A)

How they relate

Health-based goalNo known risk expected below itEnforceable limitThe legal maximum

Water between the two isn’t automatically safe. A goal and a legal limit answer different questions. Positions are illustrative, not to scale.

Is it in my water?

Only a test of your own tap can tell.

Choose what you have. We’ll show what it can and can’t tell you.

If you haven’t tested

Nobody can tell without a measurement, including us.

Three things you can do, in this order.

Test water from your tapThis is the only way to know your level. Testing guidance ↓See what your system reportsSystem results aren’t a tap measurement. Open Water Check →On a private well?Public-system reports don’t cover wells. Open Well Water →

Testing

How to test your tap water for uranium

Utilities sample to check system compliance. Your result reflects your own pipes and fixtures.

01Use a certified labA state-certified lab, or a kit that sends samples to one.
02Follow the sampling stepsHow and when you collect the water changes the result.
03Check the reportIt should state units and the detection limit.

Certified labNot sponsored

Use a state-certified labYour state keeps a list of labs certified for drinking water.

Choosing a filter for uranium

None qualify

No products currently qualify for a uranium pick here.

Nothing in our database has a uranium claim for an exact configuration we can verify.

Find a fit in Finder Read treatment approaches

Evidence

What the evidence means

We keep evidence types apart. A result for one configuration never stands in for another, and we never average across types.

No product in our database holds a reduction record for uranium yet.

How we read evidence →

Next steps

Take the next step

Match a system to your homeFinder asks about your home first. It suggests uranium as a starting point, and nothing counts until you confirm it.

Ask about uranium

Still have a question?

Answers come only from WaterDecoder’s reviewed sources and show citations. Ask can’t interpret your test result or choose a product. Don’t include personal details.

AI assistant

Ask about Uranium

Answers draw on cited public-health sources and the filters certified to reduce Uranium. Every source is linked, and if the sources don’t cover a question, the answer says so.

Questions to start with

Educational information from cited sources. Not medical or professional advice.

References

Where these facts come from

1Regulatory reference40 CFR §141.66EPA NPDWR MCL (30 µg/L)
2Regulatory reference40 CFR §141.51EPA National Primary Drinking Water Regulations — MCLG zero
3Regulatory reference22 CCR §64443 (Table 64443-A)California state MCL (20 pCi/L)

Written and maintained by WaterDecoder. A review date appears only once we have confirmed one.