Orenco's Distributing Valves are mechanically operated and sequentially redirect pump flow to multiple zones or cells in a distribution field (e.g., sand filter). The valve is actuated by pressure and flow. Automatic Distributing Valves allow the use of smaller horsepower pumps on large sand filters and drainfields. For example, a large community drainfield requiring 300 gpm can use a six-line Automatic Distributing Valve to reduce the pump flow rate requirement to only 50 gpm. We recommend the use of High Head Effluent Pumps with Biotube® Pump Vaults to provide pressure and flow requirements and to prevent debris from fouling valve operation.