Well Water Nerd

Well water in Daviess County, Missouri

1in5

Testing strongly recommended

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

16 private wells tested 2010 to 2023 in state summaries; 234 test results across 15 contaminants from at least 40 wells, 1935 to 2024; nitrate has the most at 47. Data refreshed September 15, 2026.

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

Missouri does not require private well testing, so these are samples homeowners chose to send to the state lab, often after a problem; shares above the limit run higher than a random survey would find.

An estimated 143 people in Daviess County get their drinking water from a private well, per USGS 2015 county water use. That is about 2% of residents.

Separately, the USGS national arsenic model estimates that 2% of the 143 people on private wells in Daviess County draw water above 10 ug/L (the model's range is 2% to 3%), from geology and well depth rather than local tests.

What homeowner tests found

Missouri DHSS private well sampling summaries: private wells tested and reported to the state, 2010 to 2023. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.

ContaminantAbove state levelWells testedMedian95th pctHighestState level
Iron14300 ug/L
Chloride15250 mg/L
Lead1615 ug/L
Nitrate1510 mg/L
Fluoride154 mg/L
Arsenic910 ug/L
Uranium630 ug/L

What individual samples found

Each row summarizes every public sample for that contaminant inside Daviess 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.

ContaminantAbove limitSamplesDetectedMedianHighestLimit
Nitrate
1935 to 2024
4785%3.535010 mg/L
EPA limit
Fluoride
1935 to 2024
22100%0.554.84 mg/L
EPA limit
Arsenic
1991 to 2024
229%00.1410 ug/L
EPA limit
Iron
1935 to 2024
no limit4288%42511,000300 ug/L
nuisance level
Manganese
1935 to 2024
no limit4073%551,000300 ug/L
health guideline
Chloride
1935 to 2024
no limit25100%483,000250 mg/L
nuisance level
Sodium
1935 to 2024
no limit24100%1472,20020 mg/L
health guideline

Sampled fewer than 10 times, too few to summarize: Uranium (2), Lead (2), Radium (226 + 228) (2), Copper (2), E. coli (1), PFOS (1), PFOA (1), Radon (1).

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

Among homeowners in Daviess County who sent a sample to the state lab, no health-based limit was exceeded often enough to publish a share. That is good news, but a single well can still be the exception.

Iron exceeds the state's advisory level in a sizable share of wells; this is mostly a taste, staining or diet issue rather than a toxicity one.

What to test for in Daviess County

  1. 1
    Nitrate
    19% of 47 local samples were above the limit.
  2. 2
    Fluoride
    5% of 22 local samples were above the limit.
  3. 3
    Coliform bacteria
    Recommended for every private well, every year.
  4. 4
    Radon
    Median local reading is 280 pCi/L.
  5. 5
    Iron
    43% of 14 local wells tested were above the EPA secondary standard.
  6. 6
    Chloride
    7% of 15 local wells tested were above the EPA secondary standard.
  7. 7
    Manganese
    Detected in 73% of local samples.

Test your Daviess County well for nitrate, 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 Missouri: certified labs, state programs and prices.

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

Wells in Daviess County

88 domestic wells in Daviess County are on record with the state since 1987. the typical well is 66 feet deep (one in ten goes past 225 feet).

In a typical Daviess County well, the median yield is 8 gallons per minute, 21% of wells yield under 3 gallons per minute and usually need a storage tank.

12
1990s
19
2000s
38
2010s
17
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.

  1. Open Missouri DNR WIMS and choose Water Well.
  2. The certification record lists total depth, casing length, static water level, yield and the driller.

Missouri has required certification of new private wells since 1987, so a well drilled before then usually has no record.

The rock under Daviess County

Not a principal aquifer

The USGS map places this area outside any principal aquifer, which usually means wells here draw from fractured bedrock or thin local deposits rather than a large regional aquifer. Bedrock wells of that kind are where arsenic, radon and uranium turn up, and yields vary from well to well.

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 Missouri

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.

Contamination sources on record in Daviess County

Missouri DNR records 1 regulated sites in Daviess County, among 1 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
registered underground storage tank siteRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.

Treatment that fits the local profile

Iron

Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration

Chloride

Point-of-use reverse osmosis; Distillation

Nitrate

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

Fluoride

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

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 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.

For chloride

Under-sink reverse osmosis system

under-sink or countertop, about $300

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

For nitrate

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.

Free, no obligation

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

No water treatment company serves Daviess 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 Daviess County, and you get an email naming it first.

What are you worried about?

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Common questions

How deep are wells in Daviess County?

The typical domestic well in Daviess County is 66 feet deep, based on 88 wells reported to the state since 1987. One in ten is deeper than 225 feet.

Is there arsenic in well water in Daviess County?

Arsenic was detected in 9% of 22 public well samples in Daviess 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 often should I test a private well in Daviess 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 Daviess 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 Missouri dataset as CSV, every county and town, with the sources named.

Sources

  • USGS Water Quality Portal: 234 samples in Daviess 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.
  • Missouri DHSS private well sampling summaries: summaries for 7 contaminants in Daviess County, up to 16 wells each. County summaries of private well samples analyzed by the Missouri State Public Health Laboratory, 2010 to 2023, published by the Missouri Department of Health and Senior Services. Counts are samples, not distinct wells. Shares are against the EPA maximum contaminant level, or the EPA secondary standard for chloride and iron. Counties with fewer than 20 samples are flagged unreliable by DHSS and are kept here with their counts so the threshold rule can judge them. Barium, sulfate and zinc layers exist but have no contaminant page yet. Retrieved September 15, 2026.
  • USGS national arsenic model (Ayotte 2017): estimated share of 143 people on private wells in Daviess 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.
  • Missouri DNR certified well records: 241 well records in Daviess County, 88 domestic. Well certification records from the Missouri Department of Natural Resources Wellhead Information Management System (WIMS), published through MSDIS. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 15, 2026.
  • Missouri DNR regulated sites: 1 regulated sites located in Daviess County. Permitted solid waste facilities, and leaking tank, underground tank and hazardous waste sites from the historical CARES potential contaminant site inventory, Missouri Department of Natural Resources. Retrieved September 15, 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.