## Facts

- Robinson Township adopted a zoning ordinance allowing mobile homes only in licensed mobile-home parks and requiring a building permit before erecting a building or structure.
- Donald and Merle Knoll owned an 80-acre parcel in an agricultural–residential district that was not a licensed mobile-home park.
- The Knolls placed a mobile home on the parcel and made related site improvements (including a well, septic arrangements, utility application, access clearing, and fencing).
- The Knolls did not obtain a building permit before placing the mobile home.
- The township sued to compel removal of the mobile home and sought a declaration that the mobile home was a nuisance per se under the ordinance.
- The Knolls challenged the ordinance as unconstitutional, arguing it arbitrarily prohibited a proper land use and lacked clear standards.
- The case proceeded on stipulated facts, including that the unit met the ordinance’s definition of a mobile home.

## Issues

1. Whether a township may constitutionally restrict mobile homes to mobile-home parks when, in practice, no existing or realistically available park sites exist, thereby excluding mobile homes from other residential and agricultural districts.
2. Whether a single mobile home used as a residence may be treated as a nuisance per se, and whether the restriction bears a real and substantial relation to public health, safety, morals, or general welfare.
3. Whether earlier precedent upholding similar restrictions should control when later developments undermine the assumptions supporting categorical exclusion.

## Decision

- The Michigan Supreme Court affirmed the judgment invalidating the ordinance as applied to exclude mobile homes outside mobile-home parks.
- The Court held the ordinance was unconstitutional to the extent it operated as an exclusionary measure that effectively prohibited a legitimate residential use throughout the township.
- The Court rejected the township’s attempt to classify the Knolls’ single residential mobile home as a nuisance per se absent proof of actual harm to public health, safety, morals, or general welfare.
- The Court limited the continued force of earlier precedent insofar as it approved categorical exclusion of mobile homes based on generalized assumptions.

## Legal Principles

- Zoning restrictions enacted under the police power must bear a reasonable, real, and substantial relation to public health, safety, morals, or general welfare.
- An ordinance that, in operation, excludes an otherwise lawful and recognized residential use from the entire municipality is constitutionally suspect and requires a substantial public-welfare justification grounded in more than generalized fears or stereotypes.
- A use is not meaningfully “permitted” if the only authorized locations are not realistically available for that use within the municipality.
- A municipality may not convert a lawful residential use into a nuisance per se by legislative declaration, where the use is not inherently harmful as a matter of law and no concrete evidence shows actual injury.

## Conclusion

Because restricting mobile homes to mobile-home parks where no park sites were realistically available functioned as a de facto prohibition on a legitimate form of housing, the ordinance was an unreasonable exercise of the police power, and the township could not treat the Knolls’ single residential mobile home as a nuisance per se without proof of actual harm.


Robinson Twp. v. Knoll, 410 Mich. 293, 302 N.W.2d 146 (Mich. 1981)