Anyone know why 3 drain pipe connections in deep end?

[Jaimslaw]

In the deep end, I have three separate 2" pipe ends that are covered by standard drain covers. When the pool was emptied for a replaster, the drain covers were removed. Two of the drain covers were for the typical set of two 2" pvc pipe drain lines. But a nearby third one was capped off (inside threaded cap with the square male socket on top). Anyone know what that is? I would think that if it was or meant to be bypassed by the original PB, it would have been gunnited or plastered over.

My replaster PB thought it might be a pipe that runs straight down for some hydrostatic, water table reasons. I was thinking its a backup drain line, tho I see no evidence of a capped pipe sticking up out of the ground at my equipment pad area.

Anyway, just curious to know why its there and/or what function it might serve.

Cheers.

 

[danpik]

My guess is it is to relieve any ground water that may want to cause the pool to float. When the pool is empty, it should be removed. This will allow any ground water pressure to equalize and not try to push up on the pool. Remember, and empty pool is more of a boat than it is a pool.

 

[YippeeSkippy]

I concur with Danpik..it sounds like a hydrostatic valve, a very important element to use when the pool is emptied for repair. Make sure to open it up if you ever drain the pool to avoid floating the pool out of the ground.

 

[Jaimslaw]

I wish I had opened it when the pool was empty for a couple of weeks recently just to see if any moisture or water would be seen. My property is located in a canyon at the bottom of a slope, so maybe that had something to do with having this installed. I've always been aware of the pool float possibility when empty, which has kept me from ever even thinking about emptying it during or shortly after the rainy season (which here is SoCal, is something of a distant memory).

 

[OldPoolMan]

If it is a hydrostatic valve, which I'm sure it is, was it checked to see if its workable? If your pool is an area of a high water table, it should be functionable. Pools can pop out of the ground even when full. I know, I've seen it when I used to work in the LA area. You're in SD? Big El Nino this year, lots of ground water. Something to think about.

 

[tim5055]

I seem to agree with the others that is to relieve hydro-static pressure, but from your description it does not appear to be the more common automatic valve, but something you manually open when the pool is empty. Something to remember if you should need to drain the pool again.

 

[Jaimslaw]

I suspect it was required by the city because of the pools close proximity to an underground French drain system (large 18" dia.) That the developer placed at the toe of a steep slope that comes down to my property line and is only a few feet from my pool. I'm going to look at the original plans and general spec plan notes to see if it shows up in either.

13 year pool and several emptying events with no signs of lifting. As to Any future emptying I will be opening that upto be safe.