Reno sits in the rain shadow of the Sierra Nevada, where the Truckee River emerges from Lake Tahoe and flows east through the Truckee Meadows before disappearing into Pyramid Lake in the Nevada desert. The city’s drinking water depends almost entirely on this single river system and the Sierra snowpack that feeds it. When the snow doesn’t come, Reno feels it.
The Truckee River: A Desert City’s Lifeline
The Truckee Meadows Water Authority (TMWA) serves approximately 430,000 customers in the Reno-Sparks metro area, drawing primarily from the Truckee River and supplementing with groundwater wells. The river’s flow is regulated by releases from Lake Tahoe and upstream reservoirs — a complex water rights system adjudicated by the Orr Ditch Decree of 1944.
In good snow years, the system works well. Sierra snowpack melts gradually through spring and summer, maintaining river flows and recharging groundwater. TMWA’s treatment plants process the water through conventional coagulation, filtration, and disinfection to produce water that consistently meets federal standards.
The problem is that good snow years are becoming less predictable. The Sierra Nevada snowpack has declined by roughly 20% over the past century, and climate projections indicate further reductions. During the 2012-2016 drought, Truckee River flows dropped dramatically, forcing TMWA to increase groundwater pumping and implement aggressive conservation measures.
Wildfire: The New Water Quality Threat
The fires that have ravaged the Sierra Nevada and surrounding Great Basin in recent years don’t just destroy forests and homes — they fundamentally alter watershed chemistry for years afterward.
When a watershed burns, the natural filtration provided by forest floor vegetation and root systems is eliminated. The first significant rainfall after a fire carries massive quantities of ash, sediment, heavy metals, and nutrients directly into streams and reservoirs. Post-fire runoff can spike turbidity by orders of magnitude and introduce manganese, iron, and organic compounds that complicate treatment.
The 2021 Caldor Fire burned through portions of the Eldorado National Forest near Lake Tahoe, raising alarms about potential impacts to the Truckee River watershed. While direct impacts to Reno’s intake were limited, the fire demonstrated the vulnerability of a water supply dependent on a single mountain watershed.
Post-fire debris flows are particularly dangerous for water infrastructure. Flash floods carrying burned material can overwhelm treatment plant intake screens, damage distribution infrastructure, and contaminate reservoirs with levels of organic matter that generate elevated disinfection byproducts when chlorinated.
TMWA has been developing wildfire response protocols and investing in treatment flexibility to handle post-fire water quality degradation. But the scale of wildfire risk in the Sierra Nevada — driven by a century of fire suppression and accelerating climate change — exceeds what any single utility can fully prepare for.
Arsenic in Groundwater
Nevada has some of the highest naturally occurring arsenic levels in groundwater in the United States. The volcanic and hydrothermal geology that created the state’s famous hot springs also concentrates arsenic in groundwater aquifers.
In the Reno-Sparks area, some groundwater wells have historically tested above the EPA’s arsenic MCL of 10 parts per billion. TMWA manages this through blending — mixing higher-arsenic groundwater with lower-arsenic surface water to keep the delivered water below regulatory limits — and through wellhead treatment at the most affected wells.
Private well users in Washoe County are at greater risk. Domestic wells aren’t subject to public water system monitoring requirements, and many well owners in the Truckee Meadows periphery have never tested for arsenic. The Nevada Division of Environmental Protection recommends arsenic testing for all private wells in western Nevada.
Growth Pressure
The Reno-Sparks metro has been one of the fastest-growing regions in the western United States, fueled by tech company relocations, Tesla’s Gigafactory in nearby Storey County, and remote workers fleeing California’s cost of living. The population has grown by over 100,000 in the past decade.
Every new resident, warehouse, and data center needs water. TMWA has been securing additional water rights and storage capacity, but the fundamental constraint remains: the Truckee River can only provide so much water, and that amount is likely to decrease over time as climate change reduces snowpack.
The intersection of growth and drought creates a water quality dynamic as well. During low-flow periods, the river carries the same contaminant load in less volume — concentrating whatever’s present. And increased groundwater pumping during droughts draws from deeper, potentially higher-arsenic zones of the aquifer.
What Reno Residents Can Do
TMWA’s treated water meets federal standards, and the utility’s management of a challenging source water environment is professional. Key considerations:
- Private well owners: test for arsenic, fluoride, and uranium — all naturally elevated in western Nevada groundwater.
- Review the CCR — TMWA publishes annual water quality reports.
- Conserve water — in a desert city dependent on Sierra snowpack, conservation isn’t optional; it extends the viability of the entire system.
- Prepare for wildfire impacts — if you’re in a WUI (wildland-urban interface) area, understand that fire can affect your water quality even if your home survives.
If you’re concerned about your water quality, a certified water treatment professional can help you test your water and recommend the right solution for your home.