Where meters are read and consumers billed on a bimonthly basis, one-half the total amount used during the two-month period will be considered the amount used for each month in said period; provided, that regardless of the charges for water as set forth in this chapter and depending upon the availability of water, all regular domestic consumers of filtered water within the corporate limits of the city after minimum rate has been obtained, may be charged at one-half of the regular rate for the months of June, July, August and September of each year, or between May 15th and September 15th of each year, depending upon the method by which the consumers are billed. (Ord. 1648 § 5, 1975)