Parkside Water Hardness & Quality Report (2026)

Parkside, California, in the City and County of San Francisco — a San Francisco neighborhood adjacent to Sunset and Forest Hill in western San Francisco near Ocean Beach and Golden Gate Park — receives its municipal water from the San Francisco Public Utilities Commission (SFPUC), drawing primarily from Hetch Hetchy Reservoir (Tuolumne River, Yosemite — Sierra Nevada) blended with Peninsula reservoir supplies including Crystal Springs Reservoir (San Mateo County).

The hard 184.5 mg/L hardness and elevated TDS of 581.6 mg/L are well above the typical Hetch Hetchy granite supply character (pure Hetch Hetchy: ~30-60 mg/L). The elevated reading at Parkside reflects significant Crystal Springs or San Andreas Reservoir blending — the Peninsula reservoirs drain the California Coast Range (Franciscan calcareous melange, Cretaceous Great Valley Sequence mudstone — more calcareous than the Sierra Nevada) — producing a supply substantially harder than pure Hetch Hetchy. Drought-year blending increases Peninsula water proportion significantly.

At 184.5 mg/L, Parkside's water is hard — scale builds steadily in kettles and appliances, dishwashers benefit from rinse aid, and water heaters should be descaled annually. Monthly descaling is recommended. The PFAS level of 7.4 ppt warrants a certified drinking water filter — the San Francisco western city industrial and transportation corridor, San Francisco International Airport (AFFF — in the Crystal Springs Peninsula watershed drainage area), and the Bay Area PFAS complex contribute to Parkside's readings.