1.5" in ground; 1.5" or 2" above ground. Make a difference?


New member
May 19, 2012
I have 1.5" copper pipe coming out of the ground and going back in. My above ground piping is a hodge podge of 1.5" and 2" PVC with many twists and turns. I want to repipe the above ground piping to maximize flow to my Hayward pool heater. I can eliminate many of the twists and turns when I repipe (they ended up there as the house moved through various owners over the years). I have a pretty generic setup: 1.5 HP VS pool pump, DE filter, pool heater.

In general, will it make any difference in flow rate to the heater if I use 2" PVC on everything above ground if I have 1.5" coming out of the ground? Or would the flow rate be essentially the same if I used 1.5" PVC everywhere above ground?
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Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
Tucson, AZ
Using the larger pipe through all the twists and turns will help to lower the head loss, so it will help for the pad to be 2" even if the below ground pipe is 1.5".

I would go to 2" for everything you change.