B61/100
Three Rivers Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 8,820 residents · California
What's In Three Rivers's Tap Water?
2
Contaminants Tested
1
Exceed EPA Limits
0
Above EPA Goals
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 1.92 mg/L | 1.30 mg/L | Over Limit |
EPA Violation History
1
Violation (last 5yr)
1
Unresolved
0
Health-Related
TIER 3Unresolved
Reporting Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
NPS-GRANT GROVE
Population Served
2,950
Water Source
Groundwater
System ID
CA1010501
NPS-WOLVERTON
Population Served
2,940
Water Source
Surface Water
System ID
CA5410503
NPS-ASH MOUNTAIN
Population Served
2,930
Water Source
Groundwater Under Influence of Surface Water
System ID
CA5410513
Frequently Asked Questions About Three Rivers Water
Is Three Rivers tap water safe to drink?
Three Rivers, California tap water receives a grade of B (61/100), which is considered good. Out of 22 contaminants tested, 1 exceed EPA maximum contaminant levels (MCLs) and 2 exceed health guidelines (MCLGs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in Three Rivers's water?
Of the 22 contaminants tested in Three Rivers's water supply, the most notable include Copper (90th percentile), Lead (90th percentile). 1 contaminant(s) exceed EPA legal limits (MCLs). 2 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Three Rivers have any water quality violations?
Yes, Three Rivers has 114 EPA violation(s) on record, with the most recent in 2025. Violation types include RPT, MR, MON. 99 of these are health-based violations, which are the most serious category.
Do I need a water filter in Three Rivers?
Based on EPA data, using a water filter in Three Rivers is recommended. 1 contaminant(s) exceed legal limits. An NSF-certified filter — such as a reverse osmosis or activated carbon system — can effectively reduce many common contaminants. Choose a filter certified to remove the specific contaminants found in your area.
Where does Three Rivers's tap water come from?
Three Rivers's drinking water is sourced from groundwater and supplied by NPS-GRANT GROVE and 2 other water system(s). The system serves approximately 8,820 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Three Rivers's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Three Rivers's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Three Rivers's water compare to other cities in California?
Three Rivers's water quality score of 61/100 earns a grade of B, which is considered good. This is an above-average score compared to many cities nationwide. Visit our California state page to see how all cities in the state compare.
What should I do if I'm concerned about Three Rivers's water quality?
If you have concerns about Three Rivers's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (NPS-GRANT GROVE) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.