Nitrate in Gilroy, CA Drinking Water
Nitrate data for Gilroy, California · 59,859 residents · 2 ZIP codes
Water quality records for Gilroy, California show Nitrate detections on file — a finding that places it among the contaminants worth tracking for this area.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14
Nitrate in Gilroy Tap Water
Nitrate has been detected in Gilroy, California drinking water at a maximum level of 12 ppb — below the EPA MCL of 10 mg/L (as nitrogen).
This analysis covers 59,859 residents across 2 ZIP codes in Gilroy.
Gilroy's overall water quality grade is B (80/100).
Is Nitrate in Gilroy 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 |
|---|---|---|---|
| 95020 | 12 ppm | 10 mg/L (as nitrogen) | OK |
| 95021 | 12 ppm | 10 mg/L (as nitrogen) | OK |
Average nitrate level across Gilroy: 12 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 Gilroy 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.