La Mirada Water Hardness & Quality Report (2026)

Suburban Water Systems - La Mirada serves approximately 57,102 residents in the City of La Mirada and portions of La Habra, Fullerton, and Buena Park within Los Angeles County, California. The utility draws drinking water from wells in the Main San Gabriel Groundwater Basin and Central Basin Groundwater Basin, supplemented by purchased surface water. The system includes voluntary testing and monitoring programs; the utility can be reached at 15088 Rosecrans Ave, La Mirada, CA 90638, or (562) 944-8219.

The supply is influenced by the San Gabriel River watershed, which drains the San Gabriel Mountains and flows into the alluvial basins underlying La Mirada. These groundwater basins consist of Quaternary alluvial deposits rich in minerals from weathered mountain rocks — particularly calcium and magnesium dissolved from limestone-bearing formations upstream. Purchased surface water blends with this groundwater, providing a moderately to very hard profile overall, as the underlying geology ensures persistent hardness through natural dissolution processes.

Very hard water promotes significant scale buildup in pipes, water heaters, dishwashers, washing machines, and coffee makers, reducing efficiency and shortening appliance lifespan. Regular descaling, drain screens, and vinegar soaks on faucets help with maintenance, and a water softener is strongly recommended to prevent long-term damage, improve soap efficiency, and reduce spotting on dishes. Water quality reports confirm compliance with lead and copper standards, including safe levels at local schools. Voluntary testing has detected PFAS compounds including perfluorooctanoic acid (PFOA) in La Mirada and Whittier wells; potential contaminants also include Fluoranthene, 1,4-Dioxane, nitrate and nitrite, and NDMA. Point-of-use filtration is advisable; the 2022 CCR contains detailed averages versus MCLs.