Mystery Pipes (and 2" or 1.5")

Jon B

Jun 17, 2016
St Pete, FL

I am moving my pool pump and filter about 15 feet, so I am starting to plan for extending my plumbing. While doing so, I came up with a couple mystery pipes:
  • One (marked "A" in the picture) is 1.5" and always seems to have a little water in it, usually above ground/pool level. Today, the water in it was about 12" above ground level.
  • The other (marked "B" in the picture) is a 2" that has a couple 90s and is capped.
Wondering what these "vent?" pipes might be for. They aren't under pressure and are independent of the intake or return lines. Wondering if I should cap them off under ground, where they are now, or extend them with the rest of the plumbing to the new pump/filter location.

Next question. intake and return lines are about 50' of 1.5" PVC with lots and lots of 90-degree elbows. I want to eliminate as many elbows as I can, straight pipe or 45 sweeps when necessary. I can access about half of the 1.5" PVC, but the other half is under concrete. Should I step up the 1.5" I can access to 2"? Would I have any increased flow, or would the remaining 1.5" under the concrete choke everything down regardless?

Any other tips, like 11" of straight pipe before the pump, etc.?

Thank you!


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Do you have a spa? The look like air vents for spa jets.

Connect a shopvac to a pipe and blow air into it and see if bubbles come out anyplace.

Jon B

Jun 17, 2016
St Pete, FL
No spa, nor any signs of one. Being in FL at seal level, someone once guessed that one of the pipes could be used for a pump to remove the ground water under the pool; in the event that the pool needed to be completely drained, this would keep the pool from popping out of the ground. However, when my pool was drained and resurfaced a few years ago, the builder didn't use either pipe, he just drained the pool and it didn't float out of the ground.
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