Building permits, zoning and land rules in Washtenaw County, Michigan

Yes. Washtenaw County, Michigan requires a building permit before construction or remodeling begins¹. Residential work follows the Michigan Residential Code, while the current Michigan Building Code took effect April 9, 2025⁶. The enforcing agency depends on the parcel's jurisdiction, so the county is not automatically the permit office for every township or city³. A new or altered building subject to Michigan's construction code cannot be occupied until the code official issues a certificate of occupancy⁸. A person erecting a residence for their own use and occupancy on their own property may qualify for Michigan's residential-builder licensing exemption, but that exemption concerns licensing and does not eliminate any applicable building-permit requirement⁷. The Washtenaw County Building Department inspects commercial and residential structures for compliance with the State Building Code where the county is the enforcing agency^1,2.

Confirm the enforcing agency for the parcel before applying, because building-code jurisdiction varies across Washtenaw County³. Washtenaw County has a Building Department that inspects commercial and residential structures for State Building Code compliance where the county is the enforcing agency^1,2. A township, city or another enforcing agency may receive the application elsewhere in the county, so identify the municipality from the parcel record and ask that municipality who issues its building permits before preparing plans³. Zoning approval is a separate local step: ask the parcel's township or city whether zoning approval must precede the building-permit application⁴. Septic and well questions do not move with building jurisdiction; Washtenaw County Environmental Health is the countywide contact for onsite sewage permitting⁵.

Zoning is administered at the township or municipal level in Washtenaw County, and the county planning department keeps township ordinances and maps on file⁴. Michigan law allows counties, townships, cities and villages to establish zoning districts, but the statewide framework does not identify the district or rules for a particular parcel¹¹. A complete countywide zoning determination was not confirmed, so do not infer that land is unrestricted from a county-level search. Ask the parcel's township or city about minimum lot size, setbacks, building height, lot coverage, accessory dwellings and agricultural uses before designing the project. Bridgewater Township's zoning ordinance sets setbacks by district, including its AG district, so the dimensions must come from the township's current ordinance¹².

Washtenaw County Environmental Health handles onsite sewage permitting, and a sewage permit is required before a system may be installed⁵. A soil evaluation is required before building a home that will not use a municipal or centralized sewage-treatment facility⁵. Septic permits stay with the county even where a township or city runs building permits and zoning. Installations and repairs must be performed by people certified by the county Environmental Health Division⁵. The office is at 705 North Zeeb Road, Ann Arbor, Michigan 48103, phone 734-222-3800¹³. Michigan requires household sanitary sewage to go to a municipal sewer or an onsite septic system¹⁴. Only about 12 percent of Washtenaw County soils lack severe limits for a conventional drain field, so make the soil evaluation an early purchase contingency rather than assuming a standard system will fit¹⁰. We could not confirm the county's inspection stages or permit fees; ask Environmental Health before scheduling work.

We could not confirm a countywide rule allowing RV occupancy, temporary camping or tiny-home occupancy on private land in Washtenaw County. Ask the parcel's township or city zoning office before buying land or moving a unit onto it, because local zoning districts and regulations control parcel-level land use^4,11. Michigan guidance for tiny houses proposed as resort cabins says a tiny house is not treated as a recreational unit merely because it is on wheels, and that local zoning, building, electrical, plumbing and health approvals apply in that setting⁹. That resort guidance does not establish permission to occupy a tiny house or RV on an ordinary private parcel. If the site will use septic, Washtenaw County requires the sewage permit before installation and requires a soil evaluation for a home without municipal or centralized sewer service⁵.

1. Identify the parcel's township or city and confirm which agency enforces the building code there³.
2. Ask that local zoning office which approvals, setbacks and dimensional rules apply⁴.
3. If the home will not use municipal or centralized sewer service, obtain the required soil evaluation and apply to Washtenaw County Environmental Health for the sewage permit before installation⁵.
4. Submit the building-permit application to the enforcing agency before construction begins^1,3.
5. Ask the road authority whether the proposed entrance needs approval; the Washtenaw County Road Commission requires a right-of-way permit for work in road right-of-way under its jurisdiction¹⁵.
6. Use installers certified by Washtenaw County Environmental Health for septic installation or repair⁵.
7. Complete the required inspections¹⁶, then request a certificate of occupancy before using a new or altered building covered by Michigan's construction code⁸.

Before making an offer, identify the parcel's township or city and obtain its zoning map and dimensional rules; a complete countywide answer for minimum lot size, setbacks and permitted uses was not confirmed^4,11. Make septic feasibility a contingency when municipal or centralized sewer service is unavailable, because a county soil evaluation is required and only about 12 percent of Washtenaw County soils lack severe limits for a conventional drain field^5,10. Confirm the building-code enforcing agency because jurisdiction changes by municipality³. Ask the applicable road authority about driveway access; the verified county-road permit statement applies specifically to Freedom Township¹⁵. The median property-tax bill is $5,505 a year at an effective rate of about 1.6 percent, useful context when comparing raw-land carrying costs¹⁰. We could not confirm countywide private-well, floodplain-development or land-division requirements, so ask the township or city and the relevant county office before closing.