The arsenic corridor's flagship county
Well water testing and treatment in Genesee County, Michigan
Genesee County well owners take bacteria samples to the Genesee County Health Department Environmental Health Division, 630 S. Saginaw Street in Flint, (810) 257-3603, which runs a bacteria testing lab. Arsenic, nitrate, and metals go to an EGLE-certified drinking water laboratory. The county median arsenic in USGS records is 16.6 ug/L, over the 10 ug/L federal limit.
Genesee County holds the number that defines Michigan's arsenic story: a county median of 16.6 ug/L in a USGS and MDEQ study of well records, the highest of the nine counties studied and the only median above the 10 ug/L federal limit. For the township homes around Flint that run on private wells, that makes this county the place in Michigan where testing before treating is least optional. Treatment gets sized from certified lab results, and the quote is free.
The Genesee County arsenic number
The nine-county study examined arsenic records from 3,022 domestic and public wells across Southeast Michigan and the Thumb. Genesee County sat at the top of it, per the county's USGS fact sheet (Haack and Rachol, 2000):
| Measure | Value |
|---|---|
| Genesee County median, USGS study records | 16.6 ug/L |
| Federal limit (EPA MCL) | 10 ug/L |
| Range of the nine county medians | 2.9 to 16.6 ug/L |
A median over the limit means more than half the sampled wells were over it. Read that calmly: it is a probability statement about the county, not a verdict on your tap, and plenty of Genesee wells test low. The bands and what each one calls for are laid out in Your Michigan Well Test, Explained, and the treatment lane is the arsenic removal page.
Why here? The rock under Genesee County
The Marshall Sandstone, the bedrock aquifer that runs under the Thumb and Southeast Michigan, carries naturally arsenic-rich pyrite, documented by Kolker and others, 2003 (USGS). Genesee County wells draw either from that bedrock or from the glacial deposits above it, which were partly built out of the same material. That is why two wells a road apart can disagree: the source layer, not the address, sets the odds.
The county also splits in two for water purposes. Flint and several surrounding communities run on municipal systems, which are regulated and monitored separately. This page is for everyone else: the households in Genesee County townships whose water arrives from their own well, where testing and treatment decisions belong to the owner. Iron, manganese, and hardness run through Michigan groundwater nearly everywhere, so most Genesee well reports that fail do so on more than one line; the iron and manganese and whole-house treatment pages cover those lanes.
Testing a well in Genesee County
The Genesee County Health Department Environmental Health Division, at 630 S. Saginaw Street in Flint, (810) 257-3603, is the local authority on wells here: it issues well permits, keeps well records, and runs a bacteria testing lab that accepts samples in its own sanitary bottles. Your well's construction record, if the county holds one, tells a contractor which layer the well draws from before anyone spends money.
For the chemistry that matters most in this county, arsenic plus nitrate and metals, use an EGLE-certified drinking water laboratory, and check the free well water testing guide for state-funded rounds when they open. Certified numbers are the ones treatment gets sized from.
Nearby counties in the corridor
The arsenic corridor does not stop at the county line. Two neighbors with their own pages:
Check the credentials yourself
Verify your water treatment contractor
You never have to take anyone's word for their credentials, including the contractor who quotes your job. Michigan keeps public records for the people and independent listings for the equipment. Four places to look before you sign:
EGLE contractor registration
Michigan registers water well drilling contractors and pump installation contractors through EGLE under Part 127 of the Public Health Code, renewed every year. If a project touches your well or its pump, ask for the registration number and check it with EGLE.
EGLE water well contractor registrationNSF-certified equipment
Certification to an NSF/ANSI standard means an independent lab verified the claim on the label: NSF/ANSI 44 for cation-exchange softeners, 53 for named health contaminants, 58 for reverse osmosis systems. Ask which standard a proposed unit carries, then look the model up in NSF listings.
NSF standards for water treatment systemsYour county health department
County health departments issue well permits, keep well records, and run private well sampling programs. They are the local authority on your well, and MDHHS publishes statewide guidance for well owners. Neither works for any contractor, which is exactly why their answers are useful.
MDHHS well water guidanceEGLE-certified drinking water labs
EGLE certifies the drinking water laboratories whose results Michigan health departments accept. Any treatment quote should be sized from a certified lab report, and EGLE recommends testing for coliform bacteria and nitrate every year.
How to get your water tested, EGLEThree questions worth asking any water treatment contractor
- 1. Are you registered with EGLE for any well or pump work this project involves, and what is the registration number?
- 2. Which NSF/ANSI standard is this equipment certified to, and for which specific contaminant claims?
- 3. Will you size the system from a certified lab result, and will the written quote list the water numbers it was designed around?
A referral through this site is not an endorsement, and these checks work on anyone. A good contractor answers all three without hesitation.
What it costs, and what happens after you send it
- What does well water treatment cost in Genesee County?
- There is no single price, because the contaminant decides the system. Across published national ranges, an under-sink reverse osmosis unit runs $300 to $950 installed, the common whole-house treatment classes run roughly $1,000 to $5,000, and whole-house reverse osmosis is the expensive end at $4,800 to $8,000 (HomeGuide, 2026). Those are national figures, not Michigan averages: no source publishes a Michigan average, so this site does not claim one. Your lab report is what moves a quote inside or past a range, and The water test itself has no single price here: county health departments, EGLE-certified laboratories and state-funded free rounds all price differently. The Michigan cost guide prints the full table by system with every source.
- How fast will someone get back to me?
- Your request goes to an independent licensed local water treatment contractor, usually within about an hour during the day. That contractor then reviews your lab report and quotes the work in writing on their own schedule.
- What work is covered?
- Arsenic removal, iron and manganese removal, nitrate removal, PFAS treatment, sulfur odor treatment, water softening, and whole-house well water treatment. See every service.
Only a contractor standing at your well can price your actual water.
Genesee County well water questions
Is arsenic really over the federal limit in most Genesee County wells?
In the sampled record, more than half were: a county median of 16.6 ug/L means the middle well of the USGS study records sat above the 10 ug/L federal limit. That is a statement about the study sample, not a prediction for your address, because neighboring wells finished in different layers can test very differently. What it does mean is that in Genesee County an arsenic test is baseline due diligence, not an extra.
Where do I get my well water tested in Genesee County?
The Genesee County Health Department Environmental Health Division at 630 S. Saginaw Street in Flint runs a bacteria testing lab, issues well permits, and keeps well records; call (810) 257-3603. For arsenic, metals, and nitrate, use an EGLE-certified drinking water laboratory, and watch for state-funded free testing rounds through EGLE. A certified result is the one a contractor can size equipment from.
What treatment handles a Genesee County arsenic result?
EGLE guidance names point-of-use reverse osmosis and arsenic adsorption cartridges as the most effective and practical residential fixes, because drinking and cooking water is the exposure that matters. When iron or hardness fail on the same report, common in this county, a point-of-entry system can carry part of the job. Which way to go is a sizing decision made from your actual lab numbers.
Who does the treatment work in Genesee County?
An independent licensed local contractor who works Genesee County. That contractor quotes in writing and installs. Your agreement is directly with them, and the verification checklist on this page works on any contractor you talk to.