Wis. Stat. § 281.97: Records; inspection.

Records required by the department shall be kept by the owners and the department supplied with certified copies and such other information as it may require. Agents of the department may enter buildings, structures and premises of owners supplying the public or industrial plants with water, ice, sewerage systems, sewage or refuse disposal service and private properties to collect samples, records and information, and to ascertain if the rules and orders of the department are complied with.