Nitrate in San Bernardino, CA Drinking Water
Nitrate data for San Bernardino, California · 365,027 residents · 18 ZIP codes
People in San Bernardino, California who get water from the public supply are among residents whose systems have returned Nitrate detections in EPA compliance testing.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14
Nitrate in San Bernardino Tap Water
Nitrate has been detected in San Bernardino, California drinking water at a maximum level of 8.5 ppb — below the EPA MCL of 10 mg/L (as nitrogen).
This analysis covers 365,027 residents across 18 ZIP codes in San Bernardino.
San Bernardino's overall water quality grade is B (72/100).
Is Nitrate in San Bernardino Water Safe?
Nitrate was detected in San Bernardino 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 |
|---|---|---|---|
| 92401 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92402 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92403 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92404 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92405 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92406 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92407 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92408 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92410 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92411 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92412 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92413 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92414 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92415 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92418 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92423 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92424 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
| 92427 | 8.5 mg/L | 10 mg/L (as nitrogen) | OK |
Average nitrate level across San Bernardino: 8.5 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 San Bernardino 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.