Well water in Carroll County, Indiana
No public well test results have been compiled for Carroll County yet. The USGS national arsenic model estimates that 18% of the 14,058 people on private wells there draw water with arsenic above 10 ug/L, the EPA limit, based on geology, well depth and land use rather than local tests.
The strongest signal is coliform bacteria: Recommended for every private well, every year, too few samples to carry the headline but first on the test list below.
18 test results across 10 contaminants from at least 3 wells, 1954 to 1992; nitrate has the most at 4. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
Data confidence: estimate. No state program or federal monitoring data for Carroll County has been compiled here yet, so the arsenic figure is the USGS national model, not a measurement. Treat a high estimate as a reason to test, not as your well's number. Measured results are added as states publish them.
An estimated 14,058 people in Carroll County get their drinking water from a private well, per USGS 2015 county water use. That is about 71% of residents.
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
Among contaminants with a federal limit, no tested sample in Carroll County came back above it. That is reassuring, but sampling is uneven: wells that were never tested are not in this data.
Chloride, Manganese, and Iron 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 Carroll County
- 1Coliform bacteriaRecommended for every private well, every year.
- 2RadonMedian local reading is 210 pCi/L.
- 3NitrateRecommended for every private well, especially near farms or septic systems.
- 4FluorideDetected in 100% of local samples.
- 5ChlorideDetected in 100% of local samples.
- 6ManganeseDetected in 100% of local samples.
- 7IronDetected in 100% of local samples.
- 8Volatile organic compounds (VOCs)24 leaking underground storage tank sites on record locally.
Test your Carroll County well for coliform bacteria, radon and nitrate
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 Indiana: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Carroll County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
The rock under Carroll County
Silurian-Devonian aquifers
Carbonate-rock. Limestone and dolomite move water through cracks and solution channels, sometimes very fast. Bacteria and nitrate can travel from the surface to a well in days, so annual bacteria testing matters more here than most places; hardness is a given.
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 Indiana
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.
- Well Water Quality and Testing, Indiana Department of Health
- Laboratories, IDEM
Contamination sources on record in Carroll County
IDEM records 24 leaking underground storage tank sites in Carroll County, among 26 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.
- 24
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 2
- other remediation projects
Free, no obligation
Get on the list for a free in-home water test in Carroll County
No water treatment company serves Carroll 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 Carroll County, and you get an email naming it first.
Common questions
How often should I test a private well in Carroll 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 Carroll 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 Indiana dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 18 samples in Carroll 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 14,058 people on private wells in Carroll 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.
- IDEM regulated sites: 26 regulated sites located in Carroll County. Leaking underground storage tank sites and state cleanup sites from the Indiana Department of Environmental Management. Retrieved September 16, 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.