NOTICE: Coastside County Water District's office at 766 Main Street, Half Moon Bay will be closed Wednesday, July 29, from 12-2pm. You may call and leave a non-emergency message at (650) 726-4405. For an emergency, call (650) 363-4951.
Fluoridation
Coastside County Water District has very low levels of naturally occurring fluoride in our source waters: 0.24 parts/million [ppm] in Denniston Reservoir, 0.32 ppm in the Denniston well field and 0.18 ppm in the Pilarcitos well field. The maximum contaminant level [mcl] is 2 ppm. Since the San Francisco Public Utilities Commission (SFPUC) initiated fluoridation in 2005, fluoride levels in Upper Crystal Springs Reservoir have risen from 0.2 ppm to 0.85 ppm.