Missouri county well guide

Well Water in St. Louis County, MO: Testing, Contractors and Rules

About 3,605 households in St. Louis County, 1% of the county, rely on a private well. Nobody tests that water unless the owner does.

Labs within 40 milesLicensed contractors
1%of households on a private well
Share on wells, county vs state
St. Louis County1%
Missouri average14%
17licensed contractors serve the county
<1 mito the nearest certified lab, Pace Analytical Services LLC-Hazelwood
Nostatewide test required when a home is sold

Wells are the exception in St. Louis County: about 3,605 households, under 1% of the county, are on a private well. Being in the minority means less local help, so this page gathers what applies.

Local rules for wells in St. Louis County

The rules that apply in St. Louis County are set at the state level in Missouri. 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

No permit for the owner, but the well must be built by a Missouri permitted well installation contractor to the 10 CSR 23-3 standards for its drilling area (Missouri has 13 drilling areas with different minimum casing depths, grouted casing, 50 ft from a septic tank and 100 ft from a lagoon or drainfield), and the contractor must disinfect the well, take a water sample for bacteria after construction and file a well certification report with the Missouri Geological Survey within 60 days. The State Public Health Laboratory's New Well Series (pH, fluoride, chloride, nitrate, sulfate, iron, manganese and lead) is the usual chemistry check on a new well.

Water test when a home is soldNot required statewide

No statewide requirement. The Missouri seller's disclosure asks only whether the water supply is a private well and whether the seller knows of problems. FHA, VA and USDA loans normally require a bacteria, nitrate and lead sample from a certified lab before closing.

What the state recommends

The Department of Health and Senior Services recommends testing a private well every year for coliform bacteria, and every few years for nitrate, pH, hardness, iron, manganese, lead and copper (the State Public Health Laboratory's minerals, nutrients and metals panel covers all of these plus arsenic and uranium). Add radon and radium in the Ozarks, lead and cadmium in the Old Lead Belt and Viburnum Trend mining districts, sulfate and chloride in deep northern wells, pesticides in shallow Bootheel wells, and test again after flooding, well work or a change in taste, color or smell. Karst wells and springs in the Ozarks should be retested after heavy rain.

Free or low-cost testingAvailable

No free program, but the cheapest state lab in the country: the State Public Health Laboratory tests a private well or cistern sample for total coliform and E. coli for a $10 handling fee. Pick up the kit from your local public health agency or district health office, collect the sample and hand it back for the lab's free statewide overnight courier. Chemistry panels cost more and are ordered through the same agency or the Bureau of Environmental Epidemiology (573-751-6102).

Getting your water tested near St. Louis County

The nearest certified lab is Pace Analytical Services LLC-Hazelwood in Hazelwood, in the county. There are 11 more within 40 miles, listed below with what each tests for.

9 certified labs within 40 miles

Licensed well contractors serving St. Louis County

Licensed help in St. Louis County includes Brotcke Well & Pump Inc and Brotcke Well & Pump, Inc and 15 others. Every listing was matched to the Missouri license list; the "verify" link on each profile opens the state lookup.

Well depth and water chemistry

Well depth and water chemistry in St. Louis County follow the rock underneath it. Typical wells here run 390 to 580 feet; the median of 283 domestic wells certified to the Missouri Geological Survey since 2000 is 490 feet. Contaminants worth testing for in this part of Missouri include coliform bacteria (the most common failure statewide, worst in ozark karst wells and springs after rain), nitrate (shallow wells in farm country, the bootheel and northern missouri).

Typical well depth

390 to 580 feet; the median of 283 domestic wells certified to the Missouri Geological Survey since 2000 is 490 feet

Contaminants to test for
  • Coliform bacteria (the most common failure statewide
  • Worst in Ozark karst wells and springs after rain)
  • Nitrate (shallow wells in farm country
  • The Bootheel and northern Missouri)
  • Hardness (dolomite across the Ozarks)
  • Iron and manganese (glacial till
  • Alluvium and Bootheel sands)
  • Radon and radium (locally in the Ozark aquifer)
  • Lead
  • Cadmium and zinc (Old Lead Belt
  • Viburnum Trend and Tri-State mining districts)
  • Sulfate
  • Chloride and sodium (deep bedrock wells in northern and western Missouri)
  • Arsenic (locally)
  • Pesticides (shallow Bootheel and river-bottom wells)
  • PFAS near airfields and industrial sites

Neighboring counties: St. Charles County, Jefferson County, Franklin County, Lincoln County.

What well work costs in St. Louis County

Bacteria test (coliform and E. coli)$10published Missouri lab fees
Nitrate test$10 to $80varies by lab; ask when you order
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

State Public Health Laboratory bacteria kit from any local health department ($10 handling fee). Installed costs are national 2026 ranges; local quotes vary with depth, access and materials. Sources, checked September 2026: Missouri State Public Health Laboratory, HomeGuide cost guides, Angi: cost to shock a well.

Questions St. Louis County well owners ask

How many homes in St. Louis County are on a well?

About 3,605, or 1% 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 St. Louis County?

Pace Analytical Services LLC-Hazelwood in Hazelwood, inside the county. Call first to ask whether they accept homeowner samples.

Do I need a permit to drill a well in St. Louis County?

No permit for the owner, but the well must be built by a Missouri permitted well installation contractor to the 10 CSR 23-3 standards for its drilling area (Missouri has 13 drilling areas with different minimum casing depths, grouted casing, 50 ft from a septic tank and 100 ft from a lagoon or drainfield), and the contractor must disinfect the well, take a water sample for bacteria after construction and file a well certification report with the Missouri Geological Survey within 60 days. The State Public Health Laboratory's New Well Series (pH, fluoride, chloride, nitrate, sulfate, iron, manganese and lead) is the usual chemistry check on a new well.

What does a well test cost near St. Louis County?

Published lab fees in Missouri: $10 for a bacteria test. State Public Health Laboratory bacteria kit from any local health department ($10 handling fee). Mail-in kits cost about the same as walking in.