Within Clovis, California, Radium has been detected in water samples drawn from the public supply — the results are part of the official EPA compliance record for systems here.

Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-04-05

Radium in Clovis Tap Water

Radium has been detected in Clovis, California drinking water at a maximum level of 15 pCi/L — 3x the EPA MCL.

This analysis covers 137,802 residents across 4 ZIP codes in Clovis.

Clovis's overall water quality grade is B (71/100).

Is Radium in Clovis Water Safe?

Radium was detected in Clovis water but currently falls within EPA limits. However, some health organizations argue the EPA MCL may not be protective enough.

If you are concerned, a reverse osmosis or ion exchange filter can reduce radium levels further.

Radium Levels by ZIP Code

Average radium level across Clovis: 15 pCi/L

Health Effects of Radium

• Increased risk of bone cancer (radium accumulates in bones)
• The body treats radium like calcium, storing it in bones
• Lifetime cancer risk of ~1 in 10,000 at 5 pCi/L
• No safe threshold for radioactive contamination

Health risk severity: High. Governed by the Radionuclides Rule.

How Radium Gets Into Drinking Water

• Natural radioactive decay in underground rock formations
• Groundwater sources (especially deep wells)
• Mining and industrial waste
• Higher in regions with specific geology (Midwest, parts of South)

What to Do About Radium in Clovis Water

1. Reverse osmosis (NSF 58 certified) removes 90%+ of radium
2. Ion exchange (water softeners) can reduce radium
3. Point-of-use RO at kitchen tap is most cost-effective
4. GAC filters alone are NOT effective for radium

Look for filters certified under NSF 58 for radium removal.

Related

• Radium — National Overview
• California Water Quality
• Clovis Water Quality
• Check Your ZIP Code