Temple City Water Hardness & Quality Report (2026)

Temple City, California, in Los Angeles County — a major inner San Gabriel Valley community (Temple City is incorporated as a city but contracts with the Los Angeles County Sheriff's Department for law enforcement — a major contract city model), home of the Temple City Camellia Festival (one of the oldest annual festivals in the San Gabriel Valley, celebrating the city's historic camellia plantings), a diverse Los Angeles County community with a significant Chinese-American and Taiwanese-American population (Temple City is part of the San Gabriel Valley ethnic Chinese commercial and residential cluster — a major East Asian-American community), and adjacent to Arcadia and San Gabriel in the inner San Gabriel Valley corridor — draws its municipal water supply from the Raymond Basin wells and MWD import via California American Water or the City of Temple City. Water hardness in Temple City measures 129 mg/L — classified as moderately hard.

Temple City's moderate hardness reflects the inner San Gabriel Valley Raymond Basin groundwater blend's calcareous-moderate character. The Raymond Basin groundwater at Temple City–San Gabriel Valley draws from: the Quaternary San Gabriel River alluvial fan (calcareous-moderate sand and gravel); the MWD import (SWP and Colorado River blend — calcareous-moderate). Cal Am's treatment and distribution produce the moderate 129 mg/L.

At 129 mg/L, Temple City residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended. California American Water consistently delivers water meeting all California State Water Board and EPA Safe Drinking Water Act requirements.