Michigan constitution
Article VII
Section 24

Subject to this constitution, any city or village may acquire, own or operate, within
or without its corporate limits, public service facilities for supplying water, light, heat, power,
sewage disposal and transportation to the municipality and the inhabitants thereof.
Services outside corporate limits.
Any city or village may sell and deliver heat, power or light without its corporate limits in
an amount not exceeding 25 percent of that furnished by it within the corporate limits, except
as greater amounts may be permitted by law; may sell and deliver water and provide sewage
disposal services outside of its corporate limits in such amount as may be determined by
the legislative body of the city or village; and may operate transportation lines outside the
municipality within such limits as may be prescribed by law.