Article VIII
Sec. 23: Subject to the provisions of this constitution, any city or village may acquire, own and operate, either within or without its corporate limits, public utilities for supplying water, light, heat, power and transportation to the municipality and the inhabitants thereof; and may also sell and deliver
water,heat, power and light without its corporate limits to an amount not to exceedtwenty-five25 per cent of that furnished by it within the corporate limits, and may also sell and deliver water 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 without the municipality within such limits as may be prescribed by law: Provided, That the right to own or operate transportation facilities shall not extend to any city or village of less thantwenty-five thousand25,000 inhabitants.