100. STATION METERS Each utility furnishing water service shall install at each operation such station meter and instruments as may be necessary to obtain a daily and monthly record of the total amounts of water delivered into the mains.105. PRESSURE GAUGES 1. Each utility furnishing water service in cities of 1,000 inhabitants or more shall maintain a graphic recording pressure gauge at its plant, downtown office or at some central point in the distributing system or each subdivision thereof where continuous records shall be made of the pressure in the mains at that point.2. Utilities operating in cities of 5,000 or more inhabitants shall equip themselves with one or more graphic recording pressure gauges in addition to the foregoing and shall make frequent records during periods of maximum use, each covering intervals of at least 24 hours' duration of the water pressure at various points on the system. All records or charts made by these meters shall be identified, dated and kept on file, available for inspection.