Wisconsin Statutes Utilities (Ch. 196 to 201) § 196.12. Report by public utilities; items

(1) Each public utility shall furnish to the commission, in the form and at the time the commission requires, accounts, reports or other information which shows in itemized detail:

(2) No public utility operated by a city, village or town having a population of less than 5,000 shall be required to report under this section except as to earnings, operating expenses, including depreciation and maintenance, cost of renewals, extensions and improvements to the property and the nature and amount of service furnished in such detail as the commission deems necessary, except that if the commission conducts any investigation of the public utility upon formal complaint, the commission may require the detailed reports required under sub. (1).