Recent water testing in Bronx, New York has returned Radium readings above detection thresholds.

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

Radium in Bronx Tap Water

Radium has been detected in Bronx, New York drinking water at a maximum level of 21 pCi/L — 4.2x the EPA MCL.

This analysis covers 1,426,241 residents across 25 ZIP codes in Bronx.

Bronx's overall water quality grade is D (51/100).

Is Radium in Bronx Water Safe?

If you live in an affected ZIP code, consider installing a reverse osmosis or ion exchange filter certified under NSF 58 and testing your water independently.

Radium Levels by ZIP Code

Average radium level across Bronx: 21 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 Bronx 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
• New York Water Quality
• Bronx Water Quality
• Check Your ZIP Code