Washoe County, Nevada: drinking water report. Washoe County covers the Reno-Sparks metro area in northern Nevada, with a population of about 490,000.
Washoe County covers the Reno-Sparks metro area in northern Nevada, with a population of about 490,000. Unlike Clark County's single-source dependence on Lake Mead, Washoe County draws from multiple sources – the Truckee River, local groundwater wells, and Marlette-Hobart water system delivering Sierra Nevada snowmelt. The Truckee Meadows Water Authority manages most of the urban supply, blending surface water and groundwater in proportions that shift seasonally based on snowpack and river flows.
The EPA's UCMR5 program detected PFAS at sampling points in the Truckee Meadows Water Authority system. The Reno-Stead Airport and the former Stead Air Force Base in north Reno are identified PFAS sources, with groundwater contamination documented in surrounding monitoring wells. According to the Nevada Division of Environmental Protection, two public water systems in Washoe County exceeded the EPA's PFAS MCL of 4 ppt for PFOS during 2024 monitoring.
Arsenic is another concern. Naturally occurring arsenic in the region's volcanic geology shows up in groundwater wells, and several smaller water systems in Washoe County have historically operated under arsenic compliance schedules. The Truckee River also carries agricultural runoff from upstream ranching operations in the Truckee Meadows.
Water quality in Washoe County varies with the season and with your specific source blend. During heavy snowmelt years, surface water dominates and brings different contaminant profiles than the groundwater-heavy summer supply.
Check your water to see current data for your address. If arsenic is present in your system, only reverse osmosis and specific adsorptive media filters reduce it effectively – standard carbon filters will not work. Our water filter guide specifies which systems are certified for arsenic removal. Pull your detailed report for seasonal trends, and visit our Nevada page for statewide data.