Nitrate in Walla Walla, WA Drinking Water
Nitrate data for Walla Walla, Washington · 47,127 residents · 1 ZIP code
Nitrate exposure in drinking water is tracked by EPA across the country; households in Walla Walla, Washington are among those with confirmed detections in the public water record.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14
Nitrate in Walla Walla Tap Water
Nitrate has been detected in Walla Walla, Washington drinking water at a maximum level of 5.95 ppb — below the EPA MCL of 10 mg/L (as nitrogen).
This analysis covers 47,127 residents across 1 ZIP code in Walla Walla.
Walla Walla's overall water quality grade is C (69/100).
Is Nitrate in Walla Walla Water Safe?
Nitrate was detected in Walla Walla 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 nitrate levels further.
Nitrate Levels by ZIP Code
| ZIP Code | Nitrate Level | EPA Limit | Status |
|---|---|---|---|
| 99362 | 5.95 mg/L | 10 mg/L (as nitrogen) | OK |
Average nitrate level across Walla Walla: 5.95 ppb
Health Effects of Nitrate
- Methemoglobinemia ("blue baby syndrome") in infants under 6 months
- Increased risk of colorectal and bladder cancer (long-term)
- Thyroid disease from chronic exposure
- Possible reproductive effects
Health risk severity: High. Governed by the National Primary Drinking Water Regulations.
How Nitrate Gets Into Drinking Water
- Agricultural fertilizer runoff
- Animal feedlot operations and manure
- Septic system leachate
- Urban stormwater and wastewater discharge
What to Do About Nitrate in Walla Walla Water
- Reverse osmosis is the most effective method for nitrate removal
- Ion exchange systems designed for nitrate can also work
- Standard carbon filters do NOT remove nitrate
- Boiling water increases nitrate concentration — never boil for nitrate
Look for filters certified under NSF 53 / NSF 58 for nitrate removal.