Nitrate in Rancho Cucamonga, CA Drinking Water
Nitrate data for Rancho Cucamonga, California · 211,546 residents · 5 ZIP codes
Nitrate is regulated under the Safe Drinking Water Act because of its potential health effects at elevated concentrations; for residents of Rancho Cucamonga, California, the relevant fact is that it has shown up in recent EPA compliance samples — point-of-use filtration is one option residents research, alongside reviewing the utility's published treatment data.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14
Nitrate in Rancho Cucamonga Tap Water
Nitrate has been detected in Rancho Cucamonga, California drinking water at a maximum level of 6.2 ppb — below the EPA MCL of 10 mg/L (as nitrogen).
This analysis covers 211,546 residents across 5 ZIP codes in Rancho Cucamonga.
Rancho Cucamonga's overall water quality grade is B (80/100).
Is Nitrate in Rancho Cucamonga Water Safe?
Nitrate was detected in Rancho Cucamonga 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 |
|---|---|---|---|
| 91701 | 6.2 ppm | 10 mg/L (as nitrogen) | OK |
| 91729 | 6.2 ppm | 10 mg/L (as nitrogen) | OK |
| 91730 | 6.2 ppm | 10 mg/L (as nitrogen) | OK |
| 91737 | 6.2 ppm | 10 mg/L (as nitrogen) | OK |
| 91739 | 6.2 ppm | 10 mg/L (as nitrogen) | OK |
Average nitrate level across Rancho Cucamonga: 6.2 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 Rancho Cucamonga 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.