Single family residential customers shall be assessed for sewer volume charges based upon the volume of water used during the winter months prescribed in the rate schedule. If the premises is not occupied for a cumulative period exceeding ten days during an averaging month, the utility shall assume an estimated amount of two thousand gallons per person for that month. When approved by the utility to prevent freezing of mains or service lines, usage over and above the normal usage will not used to establish the winter average nor billed as sewer usage. (Ord. 654 § 1(part), 2004)