(a) Horizontal Pump Suctions.(1) Each lift station pump must have a separate suction pipe that uses an eccentric reducer.(2) Pipes in a wet well must have a turndown-type flared intake.(b) Valves.(1) The discharge side of each lift station pump must be followed by a full-closing isolation valve and must also have a check valve.(A) A check valve must be a swing type valve with an external lever or external position indicator to show its open and closed positions.(B) An isolation valve must include an external position indicator to show its open and closed positions, unless a full-closing valve is a rising-stem gate valve.(2) A grinder pump installation may use a rubber-ball check valve or a swing-type check valve.(3) A butterfly valve, tilting-disc check valve, or any other valve using a tilting-disc in a pipe is prohibited.(c) Pipes.(1) A lift station pipe must have flanged or flexible connections to allow for removal of pumps and valves without interruption of the lift station operations.(2) Wall penetrations must allow for pipe flexure while excluding exfiltration or infiltration.(3) Pipe suction velocities must be at least 3.0 feet per second but not more than 7.0 feet per second.