A method of making a golf course green drainage system and the system made from the process which includes forming a drainage system field in a golf course green and coupling a drain pipe to the drain field for channeling water collected from the drain field. The process includes selecting a filter system having an inlet and a discharge for filtering water from the golf course green drainage field and placing the selected filter underground remotely from the golf course green and connecting the drain pipe thereto. The filter system discharge is connected to a retention pond so that water collected on a golf course green drainage field is filtered prior to being fed into the retention pond. The process includes selecting a filter having a housing and a hydrocarbon absorbent filter medium therein having a filter screen covering over the hydrocarbon absorbent medium and having a water deflector adjacent the inlet.