Well water in Washoe County, Nevada

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Testing strongly recommended

tested well samples in Washoe County exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal.

5,000 test results across 13 contaminants from at least 240 wells, 1939 to 2026; nitrate has the most at 1,685. Data refreshed September 15, 2026.

Compiled by Nick at Well Water Nerd from public records. How these pages are built

An estimated 32,060 people in Washoe County get their drinking water from a private well, per USGS 2015 county water use. That is about 7% of residents.

Separately, the USGS national arsenic model estimates that 1% of the 32,060 people on private wells in Washoe County draw water above 10 ug/L (the model's range is <1% to 2%), from geology and well depth rather than local tests.

What individual samples found

Each row summarizes every public sample for that contaminant inside Washoe County. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.

Contaminant	Above limit	Samples	Detected	Median	Highest	Limit
Arsenic 1968 to 2023	42%	209	97%	8	233	10 ug/L EPA limit
Nitrate 1961 to 2026	40%	1,685	96%	7.6	362	10 mg/L EPA limit
Uranium 1989 to 2023	9%	208	94%	3.06	150	30 ug/L EPA limit
Fluoride 1961 to 2023	1%	284	86%	0.2	7.9	4 mg/L EPA limit
Lead 1973 to 2023	<1%	207	43%	0	20	15 ug/L EPA limit
Copper 1973 to 2023	0%	208	75%	0.001	0.2	1.3 mg/L EPA limit
Radium (226 + 228) 1989 to 2016	0%	78	74%	0.075	1.5	5 pCi/L EPA limit
E. coli 2002 to 2016	0%	51	0%	0	0	0 MPN/100mL EPA limit
Chloride 1939 to 2023	no limit	859	100%	54.5	6,100	250 mg/L nuisance level
Sodium 1945 to 2023	no limit	420	100%	38.5	17,200	20 mg/L health guideline
Manganese 1973 to 2023	no limit	366	78%	1	3,230	300 ug/L health guideline
Iron 1967 to 2023	no limit	297	42%	0	5,070	300 ug/L nuisance level
Radon 1988 to 2013	no limit	128	100%	790	12,000	2,000 pCi/L health guideline

Over time

Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.

Contaminant	before 2000	2000s	2010s	2020s
Nitrate	14%353 samples	51%1,194 samples	12%108 samples	13%30 samples
Fluoride	2%130 samples	0%88 samples	0%54 samples	0%12 samples
Arsenic	38%63 samples	44%79 samples	43%54 samples	46%13 samples
Uranium	6%62 samples	9%79 samples	11%54 samples	15%13 samples
Copper	0%62 samples	0%79 samples	0%54 samples	0%13 samples
Lead	2%61 samples	0%79 samples	0%54 samples	0%13 samples

Nitrate, fluoride, arsenic, uranium, copper, lead have held within a few points between the two most recent periods with enough samples.

Closer than the county

See the sampled wells near your address

The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.

Check my address

What this means

The contaminants most often above their limit here are arsenic (42% of 209 samples), nitrate (40% of 1,685 samples), and uranium (9% of 208 samples). A well next door can differ sharply from yours because bedrock fractures, well depth and plumbing all matter, so these rates describe the area, not your tap.

Chloride and Manganese are widespread in local groundwater. They are mainly a staining and taste problem, but high manganese also carries a health advisory for infants.

What to test for in Washoe County

1
Arsenic
42% of 209 local samples were above the limit.
2
Nitrate
40% of 1,685 local samples were above the limit.
3
Uranium
9% of 208 local samples were above the limit.
4
Fluoride
1% of 284 local samples were above the limit.
5
Lead
<1% of 207 local samples were above the limit.
6
Coliform bacteria
Recommended for every private well, every year.
7
Radon
Median local reading is 790 pCi/L.
8
Volatile organic compounds (VOCs)
1,181 leaking underground storage tank sites on record locally.

Test your Washoe County well for arsenic, nitrate and uranium

Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.

Order the Tap Score well water test kit, from $209 Already tested? Upload the report

Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.

Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.

Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.

Where to get a well tested in Nevada: certified labs, state programs and prices.

Already have results back? Get your lab report read against the Washoe County numbers, $29. Every line explained, ranked by what matters, with the fix for each.

Wells in Washoe County

12,893 domestic wells in Washoe County are on record with the state since 1970. 100% are drilled into bedrock, and the typical well is 198 feet deep (one in ten goes past 440 feet).

In a typical Washoe County well, bedrock starts about 85 feet down, the median yield is 20 gallons per minute, <1% of wells yield under 3 gallons per minute and usually need a storage tank.

Bedrock wells are where arsenic, uranium and radon come from: the water sits in fractures in granite and metamorphic rock and picks up whatever the rock carries. That is why testing for those three matters more here than in a dug or gravel well.

2,928

1970s

2,081

1980s

2,467

1990s

2,182

2000s

937

2010s

557

2020s

Find your own well's report

The state keeps the driller's report for most wells drilled since 1984. It tells you how deep your well is, where bedrock starts, and how much water it makes, which decides what treatment can work.

Open NDWR well driller reports and choose Water Well.
The report lists depth, casing, static water level and the yield test.

Nevada has required driller reports since the 1940s, so most wells have one.

The rock under Washoe County

Basin and Range basin-fill aquifers

Unconsolidated sand and gravel. Wells in sand and gravel are usually shallow and productive, and they recharge quickly from the surface. That makes them the most exposed to nitrate, bacteria and anything spilled nearby, and the least likely to carry arsenic or radon from the rock.

Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the county centroid. A single well can sit in a different unit, especially near a boundary.

Official help in Nevada

Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.

Private wells, NDEP
Get Your Drinking Water Tested, NDEP

Contamination sources on record in Washoe County

NDEP corrective action release events records 1,181 leaking underground storage tank sites in Washoe County, among 1,190 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.

1,181: leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
9: other remediation projects

Treatment that fits the local profile

Arsenic

Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange

Nitrate

Point-of-use reverse osmosis; Anion exchange; Distillation

Uranium

Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange

Fluoride

Point-of-use reverse osmosis; Activated alumina; Distillation

Lead

Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching

Systems we would look at first

Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.

For arsenic

Under-sink reverse osmosis system

under-sink or countertop, about $300

Look for NSF/ANSI 58 certification listing the contaminant you need removed.

For arsenic

Whole-house arsenic and uranium filter

whole-house, at the point of entry, about $2,500

Adsorptive iron-based media; sized to your well yield.

For arsenic

Aquasana SmartFlow reverse osmosis

under-sink or countertop, about $225

Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.

For lead

Aquasana Claryum 3-Stage under-sink filter

under-sink or countertop, about $175

Certified to NSF/ANSI 53 to reduce 99% of lead and 99.7% of PFOA and PFOS at the tap. Not a fix for arsenic, nitrate or bacteria.

For lead

Acid neutralizing filter

whole-house, at the point of entry, about $1,200

Raises pH so plumbing stops leaching lead and copper.

For manganese

Iron and manganese oxidizing filter

whole-house, at the point of entry, about $1,800

Air-injection or greensand media; fixes staining at the source.

Free, no obligation

Get on the list for a free in-home water test in Washoe County

No water treatment company serves Washoe County through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Washoe County, and you get an email naming it first.

Common questions

How deep are wells in Washoe County?

The typical domestic well in Washoe County is 198 feet deep, based on 12,893 wells reported to the state since 1970. One in ten is deeper than 440 feet. 100% are drilled into bedrock.

Is there arsenic in well water in Washoe County?

Arsenic was detected in 97% of 209 public well samples in Washoe County, and 42% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.

How high is radon in well water in Washoe County?

The median radon level across 128 public samples in Washoe County was 790 pCi/L, with a high of 12,000 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.

How often should I test a private well in Washoe County?

Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.

Counties near Washoe County

Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.

Want the numbers themselves? Download the Nevada dataset as CSV, every county and town, with the sources named.

Sources

USGS Water Quality Portal: 5,000 samples in Washoe County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
USGS national arsenic model (Ayotte 2017): estimated share of 32,060 people on private wells in Washoe County above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
Nevada NDWR well driller reports: 20,413 well records in Washoe County, 12,893 domestic. Well driller reports filed with the Nevada Division of Water Resources. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 18, 2026.
NDEP corrective action release events: 1,190 regulated sites located in Washoe County. Leaking tank and other release events under corrective action at the Nevada Division of Environmental Protection. Retrieved September 18, 2026.

Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.