The corridor's low-median county
Well water treatment in Washtenaw County, Michigan
Every arsenic table on this site cites Washtenaw County: its 2.9 ug/L median was the low end of the nine-county USGS and MDEQ study, the calibration point against Genesee's 16.6. That number is good news read correctly and a trap read lazily, because the same study found wells over the federal limit in every county it touched, this one included. Ann Arbor and Ypsilanti run on municipal systems; the township homes around them run on private wells, and those owners make the testing calls. We connect Washtenaw County well owners with independent licensed contractors who work from certified lab results, free.
What 2.9 ug/L does and does not mean
The county's USGS fact sheet (Haack and Rachol, 2000) places Washtenaw at the bottom of the nine county medians, 2.9 ug/L against the 10 ug/L federal limit, from the study of 3,022 well records. What it means: the middle Washtenaw well in the study records tested comfortably under the limit, and most owners here will too. What it does not mean: that any individual well can skip the test. Every county in the study had wells above 10 ug/L, and the high ones were commonly finished in the Marshall Sandstone documented by Kolker and others, 2003 (USGS), the bedrock that reaches under this corridor.
One certified test settles it. Read your number against the bands in Your Michigan Well Test, Explained, and if it runs high, the fix is routine and local: the arsenic removal page covers it.
Two local wrinkles: the dioxane plume and hard water
Washtenaw County carries one finding most Michigan counties do not: a 1,4-dioxane groundwater plume from past manufacturing in the Scio Township and western Ann Arbor area, documented by the county, which publishes sampling results and lists laboratories that test for it. This is a location-specific question, not a countywide one: wells near the mapped plume area should use the county's resources and a listed lab, and treatment decisions there belong with the county and EGLE guidance first.
The countywide constants are quieter: hardness that scales water heaters, handled by a properly sized softener on the water softening page, and iron above the EPA secondary standard staining fixtures, covered on the iron and manganese page. What the common fixes cost, with sources, is in the Michigan cost guide.
Testing a well in Washtenaw County
The Washtenaw County Health Department publishes drinking water testing guidance and well resources through its environmental health division, including the county's 1,4-dioxane pages for plume-area addresses. Statewide, MDHHS carries the well owner guidance this site defers to.
For the chemistry a quote gets sized from, use an EGLE-certified drinking water laboratory: coliform and nitrate annually per EGLE guidance, arsenic at least once, metals and hardness when equipment is being considered. The free well water testing guide tracks state-funded rounds when they open.
Nearby counties in the corridor
The medians climb as the corridor runs north from here:
Check the credentials yourself
Verify your water treatment contractor
You never have to take anyone's word for their credentials, including anyone this site matches you with. 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?
Matching through this site is not an endorsement, and these checks work on anyone. A good contractor answers all three without hesitation.
Washtenaw County well water questions
Washtenaw County had the lowest arsenic median. Do I still need the test?
Yes, once, for any well without a number. The 2.9 ug/L figure is a median of study records, not a ceiling: every county in the nine-county USGS study, Washtenaw included, had some wells above the 10 ug/L federal limit, and the wells that ran high were commonly finished in the Marshall Sandstone. A single certified arsenic test places your well and closes the question for years.
What is the 1,4-dioxane issue in Washtenaw County?
A groundwater plume from past manufacturing in the Scio Township and western Ann Arbor area, documented by Washtenaw County, which lists laboratories for 1,4-dioxane testing and publishes sampling results. It is a location question: if your well is near the mapped plume area, use the county resources and test through a listed lab. It is not a countywide finding, and standard well tests do not screen for it unless ordered.
Where do I get well water tested in Washtenaw County?
The Washtenaw County Health Department publishes well water testing guidance and drinking water resources through its environmental health division, and EGLE-certified drinking water laboratories handle the chemistry a treatment quote gets sized from: coliform and nitrate annually per EGLE guidance, arsenic at least once, metals and hardness when equipment is on the table. Near the dioxane plume area, add a county-listed lab for that test.
Who installs well water treatment in Washtenaw County?
An independent licensed local contractor. Great Lakes Well Water is a free matching service operated by a marketing company: we connect Washtenaw County well owners with a treatment professional who works this area, that contractor sizes equipment from your certified lab result and quotes in writing, and your agreement is directly with them.