Nitrate in Chico, CA Drinking Water
Nitrate data for Chico, California · 16,121 residents · 6 ZIP codes
Routine testing in Chico, California turned up Nitrate — samples from the public supply came back positive, placing this contaminant on the list of substances residents here have a concrete reason to look into.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14
Nitrate in Chico Tap Water
Chico, California has 54 EPA violations related to nitrate in drinking water.
This analysis covers 16,121 residents across 6 ZIP codes in Chico.
Chico's overall water quality grade is B (83/100).
Is Nitrate in Chico 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.
EPA Violations for Nitrate in Chico
| Date | Violation Type | Status | ZIP Code |
|---|---|---|---|
| 2024-04-01 | Nitrate-Nitrite (Known) | Known | 95926 |
| 2024-04-01 | Nitrate-Nitrite (Known) | Known | 95927 |
| 2024-04-01 | Nitrate-Nitrite (Known) | Known | 95928 |
| 2024-04-01 | Nitrate-Nitrite (Known) | Known | 95929 |
| 2024-04-01 | Nitrate-Nitrite (Known) | Known | 95973 |
| 2024-04-01 | Nitrate-Nitrite (Known) | Known | 95976 |
| 2024-01-01 | Nitrate-Nitrite (Known) | Known | 95926 |
| 2024-01-01 | Nitrate-Nitrite (Known) | Known | 95927 |
| 2024-01-01 | Nitrate-Nitrite (Known) | Known | 95928 |
| 2024-01-01 | Nitrate-Nitrite (Known) | Known | 95929 |
| 2024-01-01 | Nitrate-Nitrite (Known) | Known | 95973 |
| 2024-01-01 | Nitrate-Nitrite (Known) | Known | 95976 |
| 2023-10-01 | Nitrate-Nitrite (Known) | Known | 95926 |
| 2023-10-01 | Nitrate-Nitrite (Known) | Known | 95927 |
| 2023-10-01 | Nitrate-Nitrite (Known) | Known | 95928 |
| 2023-10-01 | Nitrate-Nitrite (Known) | Known | 95929 |
| 2023-10-01 | Nitrate-Nitrite (Known) | Known | 95973 |
| 2023-10-01 | Nitrate-Nitrite (Known) | Known | 95976 |
| 2023-07-01 | Nitrate-Nitrite (Known) | Known | 95926 |
| 2023-07-01 | Nitrate-Nitrite (Known) | Known | 95927 |
| ... | 34 more violations |
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 Chico 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.