The size of pipes used for an inground pool can vary depending on the size and design of the pool, as well as the type of pool equipment and the flow rate required. However, the most common sizes used for inground pool plumbing are:
1.5-inch pipes are commonly used for the pool's main drain line and skimmer lines.
2-inch pipes are often used for the pool's return lines.
PVC pipes are the most commonly used type of pipe in pool plumbing, but some pools may use flexible hoses or other types of pipes.
It is important to note that the pipe size also depends on the type of pool equipment, the flow rate, and the total dynamic head (TDH) of the system. The TDH is the total resistance to flow in the system, and it includes the head loss caused by the pipe friction, valves, fittings, etc.
It is recommended that you consult with a professional pool service or pool equipment supplier to determine the appropriate pipe size for your pool. They will take into consideration all the factors that can affect the pipe size and ensure that the system is properly sized to meet the needs of your pool.