Barstow Water Hardness & Quality Report (2026)

Barstow, California, in San Bernardino County at the junction of Interstate 15 and Interstate 40 in the heart of the Mojave Desert — a historic rail and highway crossroads city serving as the gateway to the Mojave National Preserve — receives its municipal water from the City of Barstow Public Utilities Division, drawing from Mojave River Basin groundwater wells and supplementary Metropolitan Water District (MWD) imported water via the California Aqueduct. The Mojave River, though frequently dry at the surface above Barstow, sustains a productive underground aquifer recharged by seasonal flood events from the San Bernardino Mountains.

The moderately soft 108.5 mg/L hardness and TDS of 276.5 mg/L reflect Barstow's blended water supply character. The Mojave River Basin groundwater beneath Barstow contacts Quaternary alluvial deposits — sands, gravels, and silts washed from the surrounding Mojave Desert mountains during episodic floods — with some contact with Miocene volcanic and sedimentary formations in the upper basin. MWD California Aqueduct import delivers State Water Project water from the Sacramento-San Joaquin Delta that is naturally softer (~90–120 mg/L). The blended supply from these two sources falls in the moderately soft range, reflecting a city that benefits from significant treated import dilution of its desert well water.

At 108.5 mg/L, Barstow's water is moderately soft — reasonable for a Mojave Desert community. Scale accumulates gradually in kettles and appliances over months, soap lathers adequately, and the dishwasher produces clean results with standard rinse aid. Quarterly descaling of heating appliances is recommended in the dry, hot desert climate where evaporation can concentrate minerals on exposed surfaces. The PFAS level of 5.0 ppt is moderate — Barstow is a significant military-adjacent community (Fort Irwin National Training Center is nearby) but PFAS levels remain manageable.