Walnut, California: Is the Tap Water Safe to Drink?
2026 EPA water quality data for 1 community water system serving 100,941+ residents. See violations, PFAS results, lead test results, and safety grades — free.
Is Walnut Tap Water Safe to Drink?
Based on the latest EPA data, Walnut tap water meets all federal drinking water standards. All 1 tested system has received a safety grade of A or B, with no active health-based violations.
Walnut Water Quality Overview
Walnut, California is served by 1 community water system providing water to approximately 100,941 residents. The system draws from surface water purchased sources. Walnut water systems have no recorded health-based violations.
Find Your Water System
Search by ZIP code to find your exact water provider and see its full EPA report.
All 1 water system in Walnut
Looking for water quality data across the whole state? See our full California tap water safety report covering California’s EPA-regulated water systems.
Walnut Drinking Water: Frequently Asked Questions
Is Walnut, California tap water safe to drink?
Based on the latest EPA data, Walnut tap water meets all federal drinking water standards. All 1 tested system has received a safety grade of A or B, with no active health-based violations.
How many water utilities serve Walnut, California?
1 community water system serves Walnut, California, providing water to approximately 100,941 people. Different neighborhoods may be served by different utilities. Enter your ZIP code at the top to find your specific provider.
Does Walnut tap water have lead?
Lead in drinking water typically enters from old pipes and fixtures inside homes and buildings, not from the treatment plant. The EPA requires water systems to monitor for lead under the Lead and Copper Rule. Click any water system above to see its most recent 90th-percentile lead test results. Homes built before 1986 are most likely to have lead plumbing components.
What contaminants have been found in Walnut drinking water?
EPA violation records for Walnut water systems are listed on each utility's report page. Common regulated contaminants include disinfection byproducts (TTHMs, HAA5), coliform bacteria, nitrates, and lead. Click any utility above to see its full violation history going back 10 years.
How do I find out which water company serves my address in Walnut?
Enter your Walnut ZIP code in the search box at the top of this page. ClearWater will identify the specific water system serving your area and show you its EPA violation history, lead test results, and an overall safety grade. You can also check your water bill or your utility's annual Consumer Confidence Report (CCR).