Federal water monitoring extends to thousands of public water systems, and in Bryn Mawr, California, that tracking has turned up Radium — the detection is logged in the EPA compliance record and reflects samples collected under routine Safe Drinking Water Act reporting requirements.

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

Radium in Bryn Mawr Tap Water

Radium has been detected in Bryn Mawr, California drinking water at a maximum level of 9 pCi/L — 1.8x the EPA MCL.

This analysis covers 25,129 residents across 1 ZIP code in Bryn Mawr.

Bryn Mawr's overall water quality grade is D (53/100).

Is Radium in Bryn Mawr Water Safe?

Radium was detected in Bryn Mawr 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 Bryn Mawr: 9 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 Bryn Mawr 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
• Bryn Mawr Water Quality
• Check Your ZIP Code