UC Irvine Water Hardness & Quality Report (2026)

UC Irvine, California, in Orange County — a planned community centered on the University of California, Irvine campus adjacent to Tustin and Newport Beach in central Orange County — receives its water from the Irvine Ranch Water District (IRWD), drawing from the Metropolitan Water District of Southern California Colorado River Aqueduct and State Water Project, supplemented by local recycled water and Orange County Groundwater Basin imports.

The moderately hard 145 mg/L hardness and TDS of 409.2 mg/L (elevated TDS/hardness ratio ~2.8 — reflecting evaporitic loading) are essentially identical to the nearby El Camino Real (145.5 mg/L), confirming both communities receive the same MWD-sourced calcareous supply. The Colorado River Aqueduct delivers water from the Colorado River, draining the Rocky Mountains — Cretaceous Mancos Shale (calcareous), Permian Supai Formation (evaporitic — gypsum TDS contributor), and Triassic Chinle Formation (calcareous). The Colorado River evaporitic component elevates TDS relative to hardness.

At 145 mg/L, UC Irvine's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 6.1 ppt warrants a certified drinking water filter — the Orange County central campus and industrial corridor and the MWD Colorado River PFAS background contribute to UC Irvine's readings.