Pool Construction
Pool Pipe Sizing Calculator
Pick a GPM, get a pipe size. Keep suction under 6 ft/s and return under 8 ft/s — that's the bible. Anything more and you're burning energy and chewing pumps.
FAQ
Why is 6 ft/s the suction limit? +
Above 6 ft/s suction lines create cavitation risk at the pump impeller — destroys seals and impellers. Returns can run a little higher (8 ft/s) because they're pressurized.
Bigger pipe always better? +
Up to a point. Bigger pipe is more expensive and harder to trench. But for any pump pulling 50+ GPM, 2" is almost always better than 1.5". The energy savings pay for the upsize in a few months.
Flex vs rigid PVC? +
Flex is fine for short equipment-pad connections. For buried runs, always rigid PVC Sch 40 with primed/cemented joints. Flex hose develops kinks and biofilm in long runs.
Why are these velocities important for energy efficiency? +
Head loss goes up with the square of velocity. Doubling velocity quadruples head loss — pump has to work 4x harder.