Winnebago County, WI Accessory Structures: ADU Owner Occupancy (2026)
Key Facts
- Occupant
- Immediate relatives only
- Not permitted
- Independent rental unit
- Structural rule
- No separate entrance/meter/address
- Coverage
- Only where town approved zoning
Summary
Winnebago County zoning defines a mother-in-law suite as quarters accessory to, and used by, immediate relatives of the household in the principal residence, not an independently rentable unit.
17.34 Mother-in-law-suite Residential quarters accessory to, but contained entirely within, the principal residence and used by immediate relatives.
Full Breakdown
The zoning code's definition of 'mother-in-law suite' limits the use to residential quarters accessory to the principal residence that are occupied by immediate relatives of the people already living there. That occupancy limit works alongside § 23.8-474's ban on any separate address, utility meter, or independent entrance: together they establish that the suite is meant to house family members within a single household, not to function as an independently leased or rented dwelling. The rule applies only in towns where the county's general zoning ordinance is in effect under Wis. Stat. § 59.69, and it does not reach property inside Oshkosh, Neenah, Menasha, or Appleton.
Violations & Fines
Requires a zoning permit before construction; zoning administrator enforcement with $200-$300 citation forfeitures per violation, each day a separate offense, plus court costs under §§ 23.14-2, 23.14-9.
Frequently Asked Questions
Can I rent my Winnebago County mother-in-law suite to a tenant?
Who counts as an eligible occupant?
Sources & Official References
Other rules in Winnebago County
Compare Winnebago County to another location·View the Wisconsin accessory structures overview
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