Is Tap Water Safe to Drink in Stockton?
Yes, tap water in Stockton is safe to drink. The city treats Sacramento–San Joaquin Delta water at its modern Delta Water Supply plant alongside river and groundwater sources, and the supply meets EPA and California standards.
Water Source
Stockton is served by the City of Stockton Municipal Utilities Department and California Water Service, drawing on the Delta Water Supply Project plant (opened 2012, treating San Joaquin Delta water), surface water from the Calaveras and Mokelumne River systems via Stockton East Water District, and local groundwater wells.
EPA Compliance Status
Currently meets federal Safe Drinking Water Act standards and California limits. EPA records show two trihalomethane (TTHM) exceedances in 2023, at 81 and 83 µg/L against the 80 µg/L limit. Delta source water is organics- and bromide-rich, so the treatment plant was designed with membrane filtration to control disinfection byproducts.
Notable Contaminants & Context
- •Delta water carries natural organic matter and bromide that can form disinfection byproducts; Stockton's membrane treatment plant is engineered specifically to keep DBPs within limits
- •Legacy agricultural chemistry (nitrates, trace TCP regionally) affects some Central Valley wells and is monitored
- •Seasonal algae in Delta channels can cause harmless earthy tastes
How It Compares
Stockton's 2012 membrane plant was built precisely because Delta water is among the trickier municipal sources in California — the same water Southern California imports via the State Water Project — and the city treats it to full compliance at the source.
Tips
- •Check whether your address is served by the city or Cal Water; each publishes its own report
- •Earthy summer taste from Delta algae is cosmetic and filters out easily
- •No safety filter is required
Frequently Asked Questions
Sources & References
The safety rating and guidance on this page draw on the following sources. See our full methodology.
- •US EPA Safe Drinking Water Act regulations
- •EWG Tap Water Database
- •The utility's most recent Consumer Confidence Report (CCR)
- •WHO Guidelines for Drinking-water Quality