Nevada well water by county: arsenic and nitrate
Modelled arsenic and nitrate for private-well users in every Nevada county, what to test for, and where to find a certified lab. Private wells aren’t covered by the Safe Drinking Water Act.
All 17 counties
- Clark CountyWell users 26,100Arsenic about 14 in 100Nitrate 1.9 mg/L
- Washoe CountyWell users 23,200Arsenic about 20 in 100Nitrate 1.1 mg/L
- Churchill CountyWell users 10,800Arsenic about 71 in 100Nitrate 0.3 mg/L
- Nye CountyWell users 10,700Arsenic about 31 in 100Nitrate 1.3 mg/L
- Lyon CountyWell users 10,600Arsenic about 45 in 100Nitrate 0.6 mg/L
- Douglas CountyWell users 9,600Arsenic about 23 in 100Nitrate 0.6 mg/L
- Elko CountyWell users 4,500Arsenic about 16 in 100Nitrate 0.5 mg/L
- Humboldt CountyWell users 4,500Arsenic about 19 in 100Nitrate 0.6 mg/L
- Carson CityWell users 3,400Arsenic about 13 in 100Nitrate 1.1 mg/L
- Pershing CountyWell users 1,700Arsenic about 32 in 100Nitrate 0.7 mg/L
- White Pine CountyWell users 1,700Arsenic about 11 in 100Nitrate 0.5 mg/L
- Lander CountyWell users 1,500Arsenic about 28 in 100Nitrate 0.5 mg/L
- Storey CountyWell users 1,300Arsenic about 20 in 100Nitrate 0.6 mg/L
- Lincoln CountyWell users 1,100Arsenic about 18 in 100Nitrate 1.0 mg/L
- Eureka CountyWell users 700Arsenic about 21 in 100Nitrate 0.4 mg/L
- Esmeralda CountyWell users 260Arsenic about 26 in 100Nitrate 0.7 mg/L
- Mineral CountyWell users 90Arsenic about 37 in 100Nitrate 0.7 mg/L
Each mark = 1 in 100 well users the model places above 10 µg/L arsenic (scale 0–10)10 mg/L nitrate: the federal limit (MCL) for public systems
- These figures describe the area, not your well. Only a lab test shows what’s in your water.
- CDC says the Well Water Index figures “do not describe risk to individual wells.” (CDC Tracking Network)
- The arsenic model is better at spotting low-arsenic areas than at confirming high ones.
- Well-user counts are 2010 USGS estimates; tract values are averages over each census tract.
- Total coliform bacteriaEvery year
- NitrateEvery year
- Total dissolved solidsEvery year
- pHEvery year
- ArsenicAsk your local health department
EPA: Private Drinking Water Wells · CDC: Guidelines for Testing Well Water
Use a state-certified lab
Nevada Division of Environmental Protection lists the laboratories certified to test drinking water in Nevada.
Screening tells you if something is worth a closer look
A lab result is the number you can act on.
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Lab-certified results
ETR Labs Basic Water Quality Test Kit
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
- Analyzed by Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638
- Turnaround: 2–4 business days after the lab receives it
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Screening: quick check, not lab-grade
Watersafe Drinking Water Test Kit
Silver Lake Research
Lead, bacteria, nitrate, copper, iron, chlorine, hardness and pH
- Turnaround: Minutes; the bacteria test can take up to 48 hours
What it can't tell you: Each test gives a yes/no or a rough range, not a lab number, and it cannot detect PFAS or arsenic.
A mail-in kit’s lab is accredited (ISO/IEC 17025) but may not be certified by your state. For a home sale, a loan, or a health-department follow-up, use a state-certified lab.
Nevada well water
Sources: CDC Well Water Index (2024) · USGS arsenic and nitrate models · USGS domestic well populations · EPA and CDC testing guidance. Data last updated 2026-10-08. All sources →
How many people use private wells in Nevada?
About 111,600 people across 17 Nevada counties, by the USGS 2010 estimate. USGS models place about 29,900 of them in areas where wells are likely to be above the 10 µg/L arsenic limit. These are area estimates, not well results.
Are private wells regulated in Nevada?
The quality and safety of drinking water from private domestic wells are not regulated by the Federal Government under the Safe Drinking Water Act nor by most state governments and laws. (EPA) Testing and treatment are the owner's responsibility.
Where can I get my well tested in Nevada?
Nevada Division of Environmental Protection keeps the list of laboratories certified to test drinking water in Nevada. Only use laboratories that are certified to do drinking water testing. (EPA)