Plumbing Process

• Swimming pool plumbing systems contain several components, including a pool pump. In addition, swimming pool plumbing contains a drain setup, with in-ground pools having pool floor drains and waterline skimmers. All of a pool's water is taken from the pool by the pool pump, which uses suction to capture water in drains and skimmers, sending it on to the pool filter. After pool water is pumped through a pool filter, it's then sent back to the pool via water return lines and jets.
  
  

Drainage

• Water in an in-ground swimming pool's basin exits the pool through its main drain and waterline skimmers. Swimming pool main drains are located in the deepest parts of an in-ground pool. All in-ground pools also have at least one skimmer unit into which water from the pool is captured prior to being drawn into the pool pump. Water feed lines transport water from drains and skimmers and route it to the pool's pump, which is sucking that water towards it.
  
  

Pump Filtration

• When water from a swimming pool leaves the pool, it's the pool pump's suctioning power capturing it and pulling it along. Once water arrives at the pool pump, it's forced or pushed over to the other side of the pump and on to filtration. Pool pumps and pool filters, while separate, are really a single water processing point. Pool pumps use positive pressure to push water through the filter and back to the pool through the water return process.
  
  

Water Return

• Water leaving a swimming pool's filter has to be put back into the swimming pool somehow. Water returns to a swimming pool after filtration through water return lines, finally entering the pool through several water return jets or ports. During the whole water return process, the pool's pump uses pressure to force or push water through the water return lines and jets and into the pool. Pool plumbing is designed to be airtight, too, to maintain suction and positive pressure.
  
  

Considerations

• All pool plumbing systems are closed loops. Most in-ground swimming pool plumbing systems have a separate waste outflow line that allows the pool to be drained using the main drain. A pool's water heater, if included in the plumbing system, also receives water and then heats it up prior to it being returned to the pool. In-ground pools often have a feed line that allows water to be added to the pool to maintain recommended water levels.