Across the water systems that serve Sun Valley, California, Radium has appeared in EPA compliance samples — standard municipal treatment targets this contaminant, though detections in the compliance record indicate it has reached household taps at measurable levels.

Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14

Radium in Sun Valley Tap Water

Radium has been detected in Sun Valley, California drinking water at a maximum level of 8 pCi/L — 1.6x the EPA MCL.

This analysis covers 105,603 residents across 2 ZIP codes in Sun Valley.

Sun Valley's overall water quality grade is D (54/100).

Is Radium in Sun Valley Water Safe?

Radium was detected in Sun Valley 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 Sun Valley: 8 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 Sun Valley 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
• Radium in California
• California Water Quality
• Sun Valley Water Quality
• Check Your ZIP Code