Radium in Johnston, IA Drinking Water
Radium data for Johnston, Iowa · 25,233 residents · 1 ZIP code
For residents of Johnston, Iowa, Radium has appeared in public water supply sampling data.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14
Radium in Johnston Tap Water
Radium has been detected in Johnston, Iowa drinking water at a maximum level of 9 pCi/L — 1.8x the EPA MCL.
This analysis covers 25,233 residents across 1 ZIP code in Johnston.
Johnston's overall water quality grade is C (59/100).
Is Radium in Johnston Water Safe?
Radium was detected in Johnston 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
| ZIP Code | Radium Level | EPA Limit | Status |
|---|---|---|---|
| 50131 | 9 pCi/L | 5 pCi/L (combined Ra-226 + Ra-228) | Exceeds limit |
Average radium level across Johnston: 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 Johnston Water
- Reverse osmosis (NSF 58 certified) removes 90%+ of radium
- Ion exchange (water softeners) can reduce radium
- Point-of-use RO at kitchen tap is most cost-effective
- GAC filters alone are NOT effective for radium
Look for filters certified under NSF 58 for radium removal.