Wis. Stat. § 196.16: Standard measurements; accurate appliances.

(1) The commission shall fix adequate and serviceable standards for the measurement of quality, pressure, initial voltage or other condition pertaining to the supply of the product or service rendered by a public utility. The commission shall prescribe reasonable regulations for measurement, examination and testing of the product or service.

(2) The commission shall establish reasonable rules, regulations, specifications and standards to secure the accuracy of all meters and appliances for measurement of public utility service.

(3) This section does not limit any power of a municipal governing body under s. 196.58.