Routine testing in Williamstown, New Jersey turned up Radium — samples from the public supply came back positive, placing this contaminant on the list of substances residents here have a concrete reason to look into.

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

Radium in Williamstown Tap Water

Radium has been detected in Williamstown, New Jersey drinking water at a maximum level of 8.9 pCi/L — 1.78x the EPA MCL.

This analysis covers 26,179 residents across 1 ZIP code in Williamstown.

Williamstown's overall water quality grade is B (72/100).

Is Radium in Williamstown Water Safe?

Radium was detected in Williamstown 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 Williamstown: 8.9 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 Williamstown 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 New Jersey
• New Jersey Water Quality
• Williamstown Water Quality
• Check Your ZIP Code