In the event any person discharging sanitary sewage, industrial waste, water or other liquids into the City's public sanitary sewerage system either directly or indirectly, obtains part or all of the water used by him from other sources than the Water Board, such user of other water shall, at his own expense, install and maintain water meters satisfactory to the Sanitary Board for measuring all water usage other than that obtained from the Water Board, and the quantity of water used to determine the sewerage service charge shall be the sum of the quantity measured by all such meters plus the quantity of water obtained from the Water Board. (1969 Code §22-34)