Commerce Water Hardness & Quality Report (2026)

The City of Commerce in Los Angeles County receives its water primarily from the City of Commerce Water System, which is managed by Cal Water (California Water Service). This utility serves about 13,000 residents using two active groundwater wells that tap into the San Gabriel Valley Basin. For supplemental supply, they also connect to the Metropolitan Water District (MWD), accessing imported surface water from the State Water Project and the Colorado River Aqueduct. While specific treatment plants aren't named, the water undergoes standard wellhead treatment, including disinfection and corrosion control. The watershed includes the San Gabriel River drainage area and adjacent alluvial plains, contributing to the Central Groundwater Basin.

The underlying geology is characterized by thick layers of Quaternary alluvium originating from the San Gabriel Mountains. Beneath these deposits lie fractured sedimentary rocks of the Fernando Formation, dating back to the Pliocene and Miocene epochs. These formations are rich in limestone and evaporites, which readily dissolve calcium and magnesium ions as water percolates through. This prolonged contact with mineral-bearing strata is what gives the Commerce supply its distinctly hard character, a common trait in inland Southern California basins when contrasted with the softer waters found elsewhere.

This very hard water can lead to significant scale buildup in household plumbing, water heaters, and fixtures. You'll likely notice reduced efficiency and a shortened lifespan for appliances like dishwashers, washing machines, and boilers, as limescale acts as an insulator and can clog valves. To combat this, homeowners often resort to periodic descaling with vinegar, installing sediment filters, and flushing storage tanks annually. Given the hardness, installing a water softener is highly recommended to exchange minerals for sodium, thereby protecting your appliances and improving the lathering of soaps and detergents.