Castro Valley, California: Is the Tap Water Safe to Drink?
2026 EPA water quality data for 2 community water systems serving 120+ residents. See violations, PFAS results, lead test results, and safety grades — free.
Is Castro Valley Tap Water Safe to Drink?
Castro Valley currently has 1 active health-based violation across 1 of its 2 water systems. Active violations mean affected systems may not meet federal safety standards. Check individual system reports below for details.
Castro Valley Water Quality Overview
Castro Valley, California is served by 2 community water systems providing water to approximately 120 residents. These systems draw from surface water (1), groundwater (1) sources. 1 active health-based violation across Castro Valley water systems require attention. Including monitoring and reporting violations, there are 67 total violations on record.
Find Your Water System
Search by ZIP code to find your exact water provider and see its full EPA report.
All 2 water systems in Castro Valley
Looking for water quality data across the whole state? See our full California tap water safety report covering California’s EPA-regulated water systems.
Castro Valley Drinking Water: Frequently Asked Questions
Is Castro Valley, California tap water safe to drink?
Castro Valley currently has 1 active health-based violation across 1 of its 2 water systems. Active violations mean affected systems may not meet federal safety standards. Check individual system reports below for details.
How many water utilities serve Castro Valley, California?
2 community water systems serve Castro Valley, California, providing water to approximately 120 people. Different neighborhoods may be served by different utilities. Enter your ZIP code at the top to find your specific provider.
Does Castro Valley 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 Castro Valley drinking water?
EPA violation records for Castro Valley 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 Castro Valley?
Enter your Castro Valley 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).