La Canada Flintridge Water Hardness & Quality Report (2026)

La Cañada Flintridge, California, in Los Angeles County — an affluent foothill community in the Crescenta Valley at the base of the San Gabriel Mountains, adjacent to Pasadena and Glendale, home of the NASA Jet Propulsion Laboratory (JPL) (the primary US planetary science center — a Caltech facility) — receives its municipal water from the Crescenta Valley Water District (CVWD) or the La Cañada Irrigation District, which draws from the Metropolitan Water District (MWD) State Water Project import as the primary supply, supplemented by limited Verdugo Basin local groundwater production.

The very soft 34.5 mg/L hardness and very low TDS of 69.6 mg/L reflect the MWD SWP-dominant supply character of this foothill community. The State Water Project water delivered through MWD originates in the Sierra Nevada snowmelt (very soft — 30-70 mg/L at the Sacramento-San Joaquin Delta) and remains very soft after treatment and delivery to the San Gabriel Mountains foothill communities. The Crescenta Valley Water District draws predominantly from MWP import with limited local Verdugo Basin groundwater production, producing the very soft, very low-TDS supply characteristic of the western San Gabriel Mountains foothill corridor.

At 34.5 mg/L, La Cañada Flintridge's water is very soft — excellent for household use. Scale essentially never forms, soap lathers abundantly, and appliances maintain maximum efficiency. Annual descaling is more than sufficient. The PFAS level of 2.9 ppt is very good for the San Gabriel Valley foothill corridor — the NASA JPL research complex (limited direct AFFF use), and the La Cañada foothill residential zone's relatively limited industrial PFAS sources produce the low reading.