Koreatown Water Hardness & Quality Report (2026)

Koreatown, a dense mid-city neighborhood within the City of Los Angeles, receives its water supply from the Los Angeles Department of Water and Power (LADWP) — the largest municipal water utility in the United States — drawing from the same three-source blend serving greater Los Angeles: the Los Angeles Aqueduct (Owens Valley and Mono Basin Sierra Nevada water); State Water Project (SWP) imports via Castaic Lake; and groundwater from the Main San Gabriel Basin and Central Groundwater Basin (Los Angeles Basin) in Los Angeles County. Water hardness in Koreatown measures 191.5 mg/L — classified as hard.

Koreatown's hard supply reflects the mid-city LADWP distribution zone's water character, where the blended supply carries a higher proportion of Los Angeles Basin groundwater from the Central Groundwater Basin — a major Quaternary alluvial aquifer beneath the Los Angeles coastal plain and mid-city zone, recharged through the Los Angeles River system and direct percolation. This basin groundwater, having percolated through Quaternary alluvial fan sediments derived from the San Gabriel Mountains and local foothills, acquires moderate to high dissolved calcium concentrations during its residence in the alluvial system. The mid-city distribution system, combining this groundwater with softer aqueduct water, delivers water in the hard range at Koreatown service connections.

At 191.5 mg/L, Koreatown residents encounter regular hard water challenges. Scale deposits form on faucet aerators, showerheads, shower glass, and tile within weeks — monthly descaling with citric acid solution is a standard practice. Dishwashers produce better glassware results with rinse-aid, and water heaters benefit from annual inspection for element scale. LADWP consistently delivers water meeting all California SWRCB and EPA Safe Drinking Water Act requirements.