Michigan Well Water Guide: Testing, Iron and Hardness

For the roughly one in four Michigan households on a private well, almost everything about that water is the owner’s job. No utility tests it and no report arrives in the mail. This guide covers what Michigan’s own agencies — EGLE, the Michigan Department of Health and Human Services (MDHHS), and MPART — actually say about testing, the issues worth testing for, and what to do with results. It sits in our well water hub alongside our pillar guide to the best water filter for well water.

We have not hands-on tested any water or equipment for this guide. Every Michigan claim below was checked against a Michigan source — EGLE, MDHHS, MPART, or a county health department — named where the claim appears. Note: our What’s In My Water tool uses public water system data, so it cannot tell you anything about a private well.

Disclosure: TapChecked is reader-supported. If you buy through links on this page we may earn a commission, at no extra cost to you. It never changes which products we pick. See how we check and our full disclosure.

In Michigan, testing a private well is the owner’s responsibility

MDHHS states it plainly on its Care for Mi Drinking Water testing page: “If you have a private residential well, testing is your responsibility,” and “You own your water system!” Michigan requires testing when a well is constructed, but for an existing private well there is no ongoing state testing mandate — the state does not come back. A well that tested fine at drilling can change with seasons, land use, and flooding, and the only way anyone finds out is if the owner orders a test.

What MDHHS recommends, and when

MDHHS publishes a simple cadence. Every year: coliform bacteria and E. coli, nitrate, and nitrite. Every 3 to 5 years: arsenic and lead. At least once: PFAS — MDHHS recommends a PFAS test even if you do not live near a known source, and says to call 800-648-6942 if you may be in an investigation area, because testing may be free there. Test sooner if a household member is pregnant, an infant lives in the home, flooding occurred near the well, the well was repaired, or the water changes. Oakland County’s Health Division gives the same advice: testing is the owner’s responsibility, bacteria and nitrates annually, arsenic every few years.

Where to test, and what it costs

MDHHS lists three certified routes: the EGLE Drinking Water Laboratory in Lansing (517-335-8184 for a kit), your local health department — many counties offer bacteria and nitrate testing, some offer more — and Michigan-certified private laboratories. Follow sampling and shipping instructions exactly; MDHHS warns samples are easily contaminated. On cost, anchor on EGLE’s own fee schedule (effective October 1, 2026, checked November 2026): coliform and E. coli $23; nitrate and nitrite $41; partial chemistry — including hardness and iron — $66; arsenic $15; PFAS $320, plus a $13 preparation fee on many chemistry tests. So the annual core runs about $64 at the state lab before shipping, a panel with arsenic and partial chemistry lands roughly at $90–$145, and PFAS is the outlier at $320. County fees vary and can be lower, so call yours first. For sampling mechanics, see how to test water at home.

Arsenic: naturally in Michigan groundwater, concentrated in the Thumb and southeast

Arsenic is Michigan’s quiet well issue because much of it is geological, not industrial. EGLE’s arsenic guidance states that Michigan has naturally higher arsenic levels in groundwater and that arsenic is “predominantly present in the thumb region down through southeast Michigan where it naturally occurs in the geologic formation.” It has no taste, color, or smell, and EGLE is explicit that a lab analysis is the only way to know your level — hence the MDHHS every-3-to-5-years recommendation for every Michigan well, not just Thumb wells. The benchmark EGLE uses is the federal maximum contaminant level for public supplies, 0.010 mg/L (10 ppb), applied as the health advisory for private wells: above it, do not use the water for drinking or cooking. EGLE notes arsenic is not readily absorbed through the skin, so drinking and cooking water is the exposure that matters, and names point-of-use reverse osmosis and arsenic adsorption media among the practical treatments — a kitchen-tap decision for most homes.

PFAS: a site-by-site Michigan story — check MPART first

PFAS in Michigan groundwater is real, but it is a point-source story, not a statewide background condition. MPART (michigan.gov/pfasresponse) maintains the state’s list of PFAS Sites and Areas of Interest — sites where groundwater exceeds one or more of Michigan’s seven PFAS groundwater cleanup criteria — with a table showing where residential wells have been or will be sampled. Around Oscoda in Iosco County, MPART lists multiple sites tied to the former Wurtsmith Air Force Base and firefighting foam, including the AuSable Township Smith Street area, Colbath Road, and Loud Drive, with residential well sampling marked “Yes.” In Kent County, the House Street disposal area near Belmont, north of Rockford, is the documented Wolverine World Wide tannery-waste site, where over a thousand nearby properties were slated for municipal water extension. Near a listed site, check MPART and call MDHHS before paying for anything — the state may sample your home. Elsewhere, PFAS is a once-and-done $320 test, not an annual expense.

Iron and hardness: the everyday Michigan complaints

Ask a Michigan well driller or county sanitarian what fills their week and the answer is rarely exotic: orange staining, metallic taste, rotten-egg odor, and scale. EGLE’s own partial chemistry panel includes iron and hardness, which tells you what the state expects Michigan wells to need checking for. The yardsticks are the EPA secondary guidelines — iron above 0.3 ppm stains, manganese above 0.05 ppm adds black staining — and the USGS hardness scale: hard above about 121 mg/L (roughly 7 grains per gallon), very hard above 180 mg/L, bands much Michigan groundwater falls into. None of this is a health standard; it is a nuisance and appliance-life problem — but the one most Michigan well owners actually spend money on. Iron bacteria ride along; EGLE publishes dedicated guidance on them, linked from Oakland County’s well services page. Fixes are in our guide to the best iron filters for well water.

What to do with your results

• Coliform present, or any E. coli: call your local health department first — shock chlorination, finding the entry pathway, retesting — before any filter purchase.
• Nitrate above 10 mg/L or nitrite above 1 mg/L (the federal limits MDHHS cites): do not use the water for infant formula; boiling concentrates nitrate rather than removing it.
• Arsenic above 10 ppb: not for drinking or cooking untreated, per EGLE; price point-of-use reverse osmosis or adsorption for the kitchen tap.
• PFAS detections: check MPART for your area and call MDHHS at 800-648-6942; in an investigation area, state sampling may already cover your address.
• Iron, manganese, hardness: match the numbers to equipment ratings with headroom, using our iron filter guide and pillar well water guide — and keep the lab report.