Moses Lake Water Hardness & Quality Report (2026)

The City of Moses Lake Water Division provides drinking water to Moses Lake, Washington, located in Grant County. The utility operates a groundwater well field at the compound at Valley and Konishi, drawing from the Columbia Basin aquifer system. The water division is responsible for treatment, monitoring, and distribution across the city's service area, ensuring compliance with EPA and Washington State drinking water standards. Annual Consumer Confidence Reports are published and accessible through the City of Moses Lake Water Division's official website.

Moses Lake's water supply originates from the Columbia Basin aquifer, a Quaternary-age groundwater system underlain by Miocene Columbia River Basalt Group formations. The basaltic geology and sedimentary interbeds characteristic of the region contribute significant dissolved minerals—particularly calcium and magnesium—to the groundwater. This geological setting produces a hard water supply typical of eastern Washington's volcanic plateau, where basalt flows and interbedded sedimentary layers interact with percolating groundwater to release mineral content.

At the hard hardness level, Moses Lake residents may experience scale buildup in water heaters, kettles, and pipes, reduced soap and detergent effectiveness, and potential staining on fixtures and glassware. Dishwashers and washing machines may require higher detergent doses and more frequent maintenance. Many households benefit from point-of-use or whole-house water softening systems to mitigate these effects and extend appliance lifespan. According to the City of Moses Lake's 2022 Water Quality Report, no chemicals or contaminants were detected in samples for that reporting year.