Guides · Southern California

Tap water guides.

Each guide pulls every number from the same federal records behind the city reports, and each one is rebuilt when the data changes.

• Lead in Southern California Tap Water: System Results. Latest EPA lead results for 292 Southern California water systems: 206 at zero and 1 at the 0.015 mg/L action level. Every system, highest first.
• Hard Water in Orange County: City-by-City Hardness. Orange County tap water runs 230 to 270 mg/L hardness (13.5 to 15.8 grains per gallon). See your city and what softening involves.
• Southern California Water Systems With EPA Violations. Nine Southern California water systems have health-based EPA violations from the last three years. See who they serve and when each one began.
• Chlorine Byproducts (TTHM, HAA5) in Orange County Water. TTHM and HAA5 chlorine byproduct levels for 9 Orange County water systems, shown as a share of the federal limit, plus how carbon filters remove them.

Looking for one city? Browse every city report.