Water Lab (EJ Water Cooperative)
IL certified
Homeowner samples
- Coliform Bacteria
Illinois county well guide
Well Water in Clay County, IL: Testing, Contractors and Rules
About 1,352 households in Clay County, 25% of the county, rely on a private well. Nobody tests that water unless the owner does.
of households on a private well
Share on wells, county vs state
0licensed contractors serve the county
27 mito the nearest certified lab, Water Lab (EJ Water Cooperative)
Nostatewide test required when a home is sold
About one in 4 households in Clay County relies on a private well, around 1,352 homes. Outside the towns with public water, wells are the norm here.
Local rules for wells in Clay County
The rules that apply in Clay County are set at the state level in Illinois. New wells must be tested before use, and nothing is required at sale. Some counties and townships add permits or setbacks of their own, so check locally before drilling. The state's own recommendations are below.
At a glance
Water test for a new wellRequired
A permit from the county health department (or IDPH where the county has no delegated program) is required before a private well is drilled, the well must be built by an IDPH licensed water well contractor to the Illinois Water Well Construction Code (steel or approved plastic casing, grout, the setbacks from septic systems and other sources, a sanitary well cap above grade), and the contractor files a well construction report with IDPH. Under the code the new well is disinfected and a bacteria sample is collected, in most counties by the health department at the final inspection, before the well is approved for use; the health department's sign-off is what the building department wants before occupancy.
Water test when a home is soldNot required statewide
No statewide requirement. The Illinois Residential Real Property Disclosure Report asks the seller about the water supply and any known defects, and FHA, VA and USDA loans require a bacteria, nitrate and lead sample from a certified lab before closing. A few counties run point-of-sale well and septic inspection programs under local ordinance, so ask the county health department.
What the state recommends
IDPH recommends testing a private well every year for coliform bacteria and nitrate, after any repair or flooding, and whenever the taste, color or smell changes; a chemistry panel (arsenic, iron, manganese, hardness, chloride, sulfate) when the well is new or every few years; and, depending on the aquifer, radium and barium for deep sandstone wells in northern Illinois, arsenic for wells in the Mahomet and other glacial aquifers of central Illinois, and pesticides and nitrate for shallow wells in farm country. County health department labs run the bacteria test cheaply, and the IDPH state lab tests samples submitted through the county.
Free or low-cost testingAvailable
No statewide free program. Most county health departments sell a bacteria (and often nitrate) sample kit for a small fee and explain the result, and the IDPH Division of Laboratories runs the bacteria test for counties without their own lab. The Illinois State Water Survey and university extension programs run periodic free nitrate and arsenic screening clinics in farm counties.
Getting your water tested near Clay County
The nearest certified lab is Water Lab (EJ Water Cooperative) in Dieterich, about 27 miles from the county center, and it accepts samples from homeowners. There are 2 more within 40 miles, listed below with what each tests for.
3 certified labs within 40 miles
Precision Water Lab
IL certified
Homeowner samples
- Coliform Bacteria
ARDL Inc
IL certified
- Arsenic
- Full Homeowner Panel
- Hardness
- Iron and Manganese
- Lead
- Nitrate / Nitrite
Licensed well contractors serving Clay County
No licensed contractor lists Clay County as a home base or service area yet. The finder below searches the whole state; most drillers travel several counties for a job.
No listings yet for this area. Try widening your search.
Well depth and water chemistry
Well depth and water chemistry in Clay County follow the rock underneath it. Typical wells here run 100 to 160 feet; the median of 76 private water wells on the ISGS ILWATER map drilled since 2000 is 130 feet. Contaminants worth testing for in this part of Illinois include arsenic (naturally occurring in the glacial sand and gravel aquifers of central and northeastern illinois, including the mahomet aquifer, where roughly one well in ten is over the standard), iron and manganese (nearly universal in glacial aquifers).
Typical well depth
100 to 160 feet; the median of 76 private water wells on the ISGS ILWATER map drilled since 2000 is 130 feet
Contaminants to test for
- Arsenic (naturally occurring in the glacial sand and gravel aquifers of central and northeastern Illinois
- Including the Mahomet aquifer
- Where roughly one well in ten is over the standard)
- Iron and manganese (nearly universal in glacial aquifers)
- Hardness (very hard water statewide)
- Radium and barium (the deep Cambrian-Ordovician sandstone aquifer of northern Illinois)
- Coliform bacteria (old large-diameter bored and dug wells
- Common in southern Illinois)
- Nitrate and atrazine (shallow wells in corn and soybean country)
- Chloride and sodium (road salt in the Chicago collar counties
- And natural brine in deep wells)
- Hydrogen sulfide and methane (deep wells in the south and the coal counties)
- Fluoride (locally high in deep aquifers)
Neighboring counties: Richland County, Wayne County, Jasper County, Effingham County.
What well work costs in Clay County
Bacteria test (coliform and E. coli)$30published Illinois lab fees
Nitrate testIncludedpart of the bacteria test above
Broad panel (metals and minerals)$85 to $450state and university lab packages
Well inspection$250 to $550$350 to $900 with water testing
Submersible pump replacement$1,000 to $2,500installed; deep wells cost more
Pressure tank replacement$800 to $1,500installed
One treatment unit$700 to $3,500softener, iron filter or UV, installed
Multi-stage whole-house treatment$2,500 to $10,000+several units or whole-house RO, installed
New well, complete$6,000 to $16,000typical 200 ft well with pump; drilling alone about $20 to $30 per foot; deeper wells cost more
Shock chlorination$80 to $200by a contractor; under $30 to do yourself
County health department lab: one $30 test covers coliform, E. coli and nitrate (McHenry County). Installed costs are national 2026 ranges; local quotes vary with depth, access and materials. Sources, checked September 2026: McHenry County Health Department lab, HomeGuide cost guides, Angi: cost to shock a well.
Questions Clay County well owners ask
How many homes in Clay County are on a well?
About 1,352, or 25% of households, based on Census housing data and state well surveys. The share is highest outside the towns with public water.
Where is the closest certified lab to Clay County?
Water Lab (EJ Water Cooperative) in Dieterich, about 27 miles away. It accepts homeowner samples.
Do I need a permit to drill a well in Clay County?
A permit from the county health department (or IDPH where the county has no delegated program) is required before a private well is drilled, the well must be built by an IDPH licensed water well contractor to the Illinois Water Well Construction Code (steel or approved plastic casing, grout, the setbacks from septic systems and other sources, a sanitary well cap above grade), and the contractor files a well construction report with IDPH. Under the code the new well is disinfected and a bacteria sample is collected, in most counties by the health department at the final inspection, before the well is approved for use; the health department's sign-off is what the building department wants before occupancy.
What does a well test cost near Clay County?
Published lab fees in Illinois: $30 for a bacteria test that also covers nitrate. County health department lab: one $30 test covers coliform, E. coli and nitrate (McHenry County). Mail-in kits cost about the same as walking in.