Well water in Davis County, Utah
1in3
Testing strongly recommended
tested well samples in Davis County exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal.
1,923 test results across 12 contaminants from at least 122 wells, 1943 to 2021; chloride has the most at 441. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 1,893 people in Davis County get their drinking water from a private well, per USGS 2015 county water use. That is about <1% of residents.
Separately, the USGS national arsenic model estimates that 1% of the 1,893 people on private wells in Davis 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 Davis 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 1989 to 2021 | 45 | 82% | 1 | 44 | 10 ug/L EPA limit | |
| Uranium 1969 to 2021 | 44 | 61% | 0.007 | 198 | 30 ug/L EPA limit | |
| Lead 1989 to 2021 | 21 | 43% | 0 | 20 | 15 ug/L EPA limit | |
| Nitrate 1943 to 2021 | 365 | 86% | 0.7 | 38.8 | 10 mg/L EPA limit | |
| Fluoride 1943 to 2021 | 299 | 96% | 0.2 | 4.4 | 4 mg/L EPA limit | |
| Copper 1984 to 2017 | 20 | 40% | 0 | 0.008 | 1.3 mg/L EPA limit | |
| Chloride 1943 to 2021 | no limit | 441 | 100% | 29 | 1,190 | 250 mg/L nuisance level |
| Sodium 1943 to 2021 | no limit | 293 | 100% | 50 | 530 | 20 mg/L health guideline |
| Iron 1943 to 2021 | no limit | 229 | 94% | 30 | 2,410 | 300 ug/L nuisance level |
| Manganese 1966 to 2021 | no limit | 153 | 90% | 11 | 480 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Radium (226 + 228) (6), Radon (7).
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 | 2%319 samples | 14%22 samples | 5%22 samples | n/a |
| Fluoride | <1%260 samples | 0%17 samples | 0%20 samples | n/a |
| Uranium | 10%10 samples | 33%12 samples | 10%20 samples | n/a |
| Arsenic | n/a | 33%12 samples | 43%23 samples | n/a |
Nitrate above the limit in Davis County fell from 14% of 22 samples in the 2000s to 5% of 22 in the 2010s.
Fluoride has 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 addressWhat this means
The contaminants most often above their limit here are arsenic (36% of 45 samples), uranium (16% of 44 samples), and lead (5% of 21 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, Iron, 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.
The median radon reading (2,110 pCi/L) is above the 2,000 pCi/L level at which treatment is recommended. Radon in water raises indoor air radon when it is used for showers and laundry.
What to test for in Davis County
- 1Arsenic36% of 45 local samples were above the limit.
- 2Uranium16% of 44 local samples were above the limit.
- 3Lead5% of 21 local samples were above the limit.
- 4Nitrate3% of 365 local samples were above the limit.
- 5Fluoride<1% of 299 local samples were above the limit.
- 6Coliform bacteriaRecommended for every private well, every year.
- 7RadonMedian local reading is 2,110 pCi/L.
- 8Volatile organic compounds (VOCs)262 leaking underground storage tank sites on record locally.
- 9Metals panel27 hazardous waste sites on record locally.
Test your Davis County well for arsenic, uranium and lead
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 $209Already 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 Utah: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Davis County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under Davis 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 Utah
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.
- Drinking Water Consumer Information, Utah DEQ
- Certifications, Utah Public Health Laboratory
Contamination sources on record in Davis County
Utah DEQ records 262 leaking underground storage tank sites and 27 hazardous waste sites in Davis County, among 448 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.
- 262
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 27
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 159
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
Treatment that fits the local profile
Arsenic
Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
Uranium
Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange
Lead
Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching
Nitrate
Point-of-use reverse osmosis; Anion exchange; Distillation
Fluoride
Point-of-use reverse osmosis; Activated alumina; Distillation
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.
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Common questions
Is there arsenic in well water in Davis County?
Arsenic was detected in 82% of 45 public well samples in Davis County, and 36% 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 often should I test a private well in Davis 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 Davis 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 Utah dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 1,923 samples in Davis 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 1,893 people on private wells in Davis 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.
- Utah DEQ regulated sites: 448 regulated sites located in Davis County. Underground storage tank facilities, CERCLA site assessments and National Priorities List sites from the Utah Department of Environmental Quality. 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.