Utah well water by county: arsenic and nitrate
Modelled arsenic and nitrate for private-well users in every Utah county, what to test for, and where to find a certified lab. Private wells aren’t covered by the Safe Drinking Water Act.
All 29 counties
- Utah CountyWell users 16,600Arsenic about 5 in 100Nitrate 1.2 mg/L
- Salt Lake CountyWell users 7,000Arsenic about 5 in 100Nitrate 1.5 mg/L
- Duchesne CountyWell users 5,900Arsenic about 8 in 100Nitrate 0.1 mg/L
- Tooele CountyWell users 5,800Arsenic about 5 in 100Nitrate 1.6 mg/L
- Cache CountyWell users 4,600Arsenic about 8 in 100Nitrate 0.7 mg/L
- Iron CountyWell users 3,900Arsenic about 11 in 100Nitrate 0.9 mg/L
- San Juan CountyWell users 3,800Arsenic about 9 in 100Nitrate 0.5 mg/L
- Davis CountyWell users 3,600Arsenic about 5 in 100Nitrate 0.6 mg/L
- Weber CountyWell users 3,200Arsenic about 7 in 100Nitrate 0.3 mg/L
- Box Elder CountyWell users 3,000Arsenic about 13 in 100Nitrate 0.6 mg/L
- Wasatch CountyWell users 2,800Arsenic about 5 in 100Nitrate 0.4 mg/L
- Summit CountyWell users 2,700Arsenic about 6 in 100Nitrate 0.2 mg/L
- Sanpete CountyWell users 2,500Arsenic about 4 in 100Nitrate 0.6 mg/L
- Morgan CountyWell users 2,400Arsenic about 6 in 100Nitrate 0.2 mg/L
- Millard CountyWell users 2,300Arsenic about 12 in 100Nitrate 0.3 mg/L
- Uintah CountyWell users 1,800Arsenic about 7 in 100Nitrate 0.2 mg/L
- Sevier CountyWell users 1,600Arsenic about 12 in 100Nitrate 0.7 mg/L
- Washington CountyWell users 1,200Arsenic about 7 in 100Nitrate 1.0 mg/L
- Grand CountyWell users 1,200Arsenic about 6 in 100Nitrate 0.5 mg/L
- Beaver CountyWell users 730Arsenic about 11 in 100Nitrate 0.5 mg/L
- Juab CountyWell users 710Arsenic about 9 in 100Nitrate 0.8 mg/L
- Garfield CountyWell users 560Arsenic about 8 in 100Nitrate 0.5 mg/L
- Rich CountyWell users 510Arsenic about 16 in 100Nitrate 0.1 mg/L
- Wayne CountyWell users 320Arsenic about 10 in 100Nitrate 0.2 mg/L
- Piute CountyWell users 160Arsenic about 17 in 100Nitrate 0.1 mg/L
- Kane CountyWell users 150Arsenic about 6 in 100Nitrate 0.4 mg/L
- Carbon CountyWell users 100Arsenic about 5 in 100Nitrate 0.3 mg/L
- Emery CountyWell users 90Arsenic about 6 in 100Nitrate 0.1 mg/L
- Daggett CountyWell users 70Arsenic about 5 in 100Nitrate 0.1 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
Utah Department of Health & Human Services lists the laboratories certified to test drinking water in Utah.
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.
Utah 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 Utah?
About 79,200 people across 29 Utah counties, by the USGS 2010 estimate. USGS models place about 5,500 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 Utah?
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 Utah?
Utah Department of Health & Human Services keeps the list of laboratories certified to test drinking water in Utah. Only use laboratories that are certified to do drinking water testing. (EPA)