Martinez Lake Water Quality

16 EPA violations on record (most recent 2022). Arsenic is a naturally occurring element that dissolves into groundwater from rock and is also released by mining and industry. Long-term exposure is associated with several cancers and with skin, cardiovascular, and developmental harm. It is common in parts of the Southwest.

2 EPA violations on record (most recent 2025). TTHM form when chlorine used to disinfect water reacts with natural organic matter. Long-term exposure has been linked to increased cancer risk and to harm in pregnancy. Levels often rise in warmer months and in systems with more organic material.

2 EPA violations on record (most recent 2025). HAA5 are a second group of chlorine disinfection byproducts formed when chlorine reacts with organic matter in water. Long-term exposure is associated with increased cancer risk and possible developmental effects. They commonly occur together with trihalomethanes.

Martinez Lake's water is very hard. Hardness isn't a health risk, but it drives scale on fixtures and water heaters, shortens appliance life, and leaves skin and hair dry.