Wis. Admin. Code § PSC 140.015 – Filing areas of service.

(1) Map. Within 3 months after the date of this order each public heating utility shall file a map showing the location of its heating facilities and the area or areas in which it considers itself obligated to serve.
(2) Furnishing information. All utilities, other than heating utilities, which furnish heat in connection with utility service of another type shall notify this commission within 3 months of the date of this order and shall keep the commission currently informed thereafter of what customers are being furnished with such heating service.