Well water in Denver County, Colorado
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Testing strongly recommended
tested well samples in Denver County exceeded the EPA limit for uranium (30 ug/L), based on public data from USGS Water Quality Portal.
672 test results across 12 contaminants from at least 77 wells, 1955 to 1999; iron has the most at 135. Data refreshed September 3, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
What individual samples found
Each row summarizes every public sample for that contaminant inside Denver 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 |
|---|---|---|---|---|---|---|
| Uranium 1993 to 1999 | 42 | 95% | 32.4 | 156 | 30 ug/L EPA limit | |
| Fluoride 1955 to 1995 | 114 | 100% | 1 | 4.1 | 4 mg/L EPA limit | |
| Radium (226 + 228) 1999 | 78 | 59% | 0.11 | 1 | 5 pCi/L EPA limit | |
| Arsenic 1977 to 1999 | 53 | 45% | 0 | 6 | 10 ug/L EPA limit | |
| Lead 1979 to 1999 | 47 | 13% | 0 | 1 | 15 ug/L EPA limit | |
| Copper 1979 to 1999 | 47 | 91% | 0.003 | 0.739 | 1.3 mg/L EPA limit | |
| Iron 1957 to 1999 | no limit | 135 | 81% | 50 | 17,000 | 300 ug/L nuisance level |
| Manganese 1955 to 1999 | no limit | 118 | 85% | 1,125 | 8,180 | 300 ug/L health guideline |
| Radon 1993 | no limit | 13 | 100% | 750 | 1,240 | 2,000 pCi/L health guideline |
| Chloride 1965 to 1993 | no limit | 12 | 100% | 47.5 | 410 | 250 mg/L nuisance level |
Sampled fewer than 10 times, too few to summarize: Nitrate (4), Sodium (9).
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 uranium (52% of 42 samples) and fluoride (<1% of 114 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.
Iron, Manganese, and Chloride 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 Denver County
- 1Uranium52% of 42 local samples were above the limit.
- 2Fluoride<1% of 114 local samples were above the limit.
- 3Coliform bacteriaRecommended for every private well, every year.
- 4RadonMedian local reading is 750 pCi/L.
- 5NitrateAbove the limit in 1 of 4 local samples; too few to quote a rate.
- 6ChlorideDetected in 100% of local samples.
- 7CopperDetected in 91% of local samples.
Test your Denver County well for uranium, fluoride and coliform bacteria
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 Colorado: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Denver County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under Denver County
Denver Basin aquifer system
Sandstone. Sandstone wells draw from pore space in the rock and tend to be dependable. Iron, manganese and hardness are common, and some sandstones carry arsenic or radium, so a first test should include both.
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 Colorado
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.
Treatment that fits the local profile
Uranium
Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange
Fluoride
Point-of-use reverse osmosis; Activated alumina; Distillation
Iron
Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Manganese
Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
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 uranium
Under-sink reverse osmosis system
under-sink or countertop, about $300
Look for NSF/ANSI 58 certification listing the contaminant you need removed.
For uranium
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 fluoride
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 iron
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 Denver County
No water treatment company serves Denver 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 Denver County, and you get an email naming it first.
Common questions
Is there arsenic in well water in Denver County?
Arsenic was detected in 45% of 53 public well samples in Denver County, and 0% 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 Denver County?
The median radon level across 13 public samples in Denver County was 750 pCi/L, with a high of 1,240 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Denver 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 Denver 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 Colorado dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 672 samples in Denver 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.
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.