Nitrate in Fresno, CA Drinking Water
Nitrate data for Fresno, California · 620,656 residents · 58 ZIP codes
ZipCheckup's reading of Nitrate in Fresno, California: the highest detected level is 13 ppb; the EPA limit is 10 mg/L (as nitrogen). Nitrate carries a high health-risk designation.
For residents of Fresno, California, Nitrate has appeared in public water supply sampling data.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-07-13
Nitrate in Fresno Tap Water
Nitrate has been detected in Fresno, California drinking water at a maximum level of 13 mg/L — 1.3x the EPA MCL.
This analysis covers 620,656 residents across 58 ZIP codes in Fresno.
Fresno's overall water quality grade is B (73/100).
Is Nitrate in Fresno Water Safe?
If you live in an affected ZIP code, consider installing a reverse osmosis or ion exchange filter certified under NSF 53 / NSF 58 and testing your water independently.
Nitrate Levels by ZIP Code
| ZIP Code | Nitrate Level | EPA Limit | Status |
|---|---|---|---|
| 93650 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93701 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93702 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93703 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93704 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93705 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93706 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93707 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93708 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93709 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93710 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93711 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93712 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93714 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93715 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93716 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93717 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93718 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93720 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93721 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93722 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93723 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93724 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93725 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| 93726 | 13 mg/L | 10 mg/L (as nitrogen) | Exceeds limit |
| ...33 more ZIP codes |
Average nitrate level across Fresno: 13 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 Fresno 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.