Pool Builders PLZ help.

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Butcher

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Aug 13, 2010
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Well I have started excavation for the wall that will retain the back side of my pool. While excavating we hit what I was concerned about, the water table. The elevation of the top of the retaining wall block was going to be the elevation of the bottom of the shallow end (see attached picture). As you can see after sitting all night the water table has risen up to within 5 inches of the top of the block or bottom of the shallow end. The deep end for this pool was going to be 2 feet deeper than the shallow end putting it about a foot and a half into the water table. I found a site that recommended putting pipe With holes in it below the deep end in stone and plumbing that to the pool pump.
I live in a cold winter climate which means the pool pump will be shut down for the fall and winter so no sump during that time. The next option I have come across is building a well point system with a submersible pump in a pipe buried in stone below the elevation of the bottom of the deep end. This is probably the lowest water table at this time of year and I am worried about the sump running at least three seasons of the year.

Next option is a relief valve in the main drain ( wasn't planning on using a main drain and even if I did there will be a lot of water entering the pool.)

SO this is where I am at now. Help Please!

My final option would be to raise the elevation of the pool and get it outta the water table. This would mean raising the height of the pool about 1 1/2 feet higher than the surrounding patio area. Wouldn't look to good though and would be very high to the surrounding back of the property.

How bad is it to have a sump system running all the time and what are my other options?
 

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I am not a builder and I have not dealt with THAT much water when I built my pool, but I see NO OTHER option than to sump it out and keep it sumped 24/7.

What about PB's in your area? Certainly they have experienced this before and may have some insight.

Once built, I would unquestionably put 1" or so rock in the overdig and have a french drain surrounding the entire pool leading to a wellpoint.
 
I am no pool builder, but I lived through Hurricane Floyd here in NJ in 1999. My pool pump and sump pump (the old pedestal kind) in the poolhouse basement did not. 15 inches of rain and 72 hours without power while I was traveling did them in. At least provide back-up power if you do go the sump pump route. Power failures can occur anywhere, you don't need a hurricane.
 
Right now I am leaning towards raising the pool 1 foot which would only put the deep end about 6 inches into the water table and only about three feet into the ground. I don't think there could be enough pressure to float the liner at that depth. I would still go with a sump pump just in case. At least I know it would not have to run all the time but would be there for back up. not sure what to do about a power outage.
 
After a lot more research I think I will be OK. The level of the water on the outside of the pool would have to be higher than the level of the water on the inside of the pool in order to float the liner. Since I am building a retaining wall the top of the pool will be about 2 1/2 feet higher than the ground level behind the wall. The only way the water table level could reach the height of the top of the pool is if the whole backyard was under 2 1/2 feet of water. At this point the water would be coming into my house and the pool would be the least of my concerns.

Is this correct?
I knew I shouldn't have missed this class at school! LOL
 

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I think you will be ok. The one thing i would consider is stacking the retaining wall up so the top of the wall is at the top of the pool. I'm not sure how its going to work if the top of the wall is at the grade of the shallow end. The polols I've seen with walls like that, including my own, have the top of the wall and top of the pool on the same grade.
 
Thanks for the reply,

Yes, that is only the first course of block. I set the bottom of the retaining wall at an elevation of one course bellow the bottom of the shallow end that is why I know that the top of that block is the elevation of the bottom of the shallow end. There will be three more courses of block on top of that one to get to the height of the top of the pool. I am still going to put about 6-8 inches of 3/4 clear crushed limestone under the concrete for the bottom of the pool and deeper in the deep end leading to a sump pump that I can also use to lower the water table when and if a new liner needs to be installed.
 
You should be ok as long as there is always water "IN" the pool. The pressure of the water coming up from under the pool would have to be greater than the pressure/weight of the water that is inside the pool. I would put a pump underneath, and run it 24/7 until you get the pool built and completely filled with water, then it's probably safe to turn off. Also be sure to run the pump if you ever have to drain the pool.
 
jasonlmarsh said:
You should be ok as long as there is always water "IN" the pool. The pressure of the water coming up from under the pool would have to be greater than the pressure/weight of the water that is inside the pool. I would put a pump underneath, and run it 24/7 until you get the pool built and completely filled with water, then it's probably safe to turn off. Also be sure to run the pump if you ever have to drain the pool.
Click to expand...

That's what I thought too.
 
It might be easier than you think for the pressure outside your pool to be higher than you would like for it to be.
My neighbor has had floating liner issues for years even with a full pool. We got a large amount of rain last year and it raised his liner a bunch. Floated all his foam up to the top and popped the liner out of the bead.
 
danbutter said:
It might be easier than you think for the pressure outside your pool to be higher than you would like for it to be.
My neighbor has had floating liner issues for years even with a full pool. We got a large amount of rain last year and it raised his liner a bunch. Floated all his foam up to the top and popped the liner out of the bead.
Click to expand...

But if the ground behind the pool is 2 1/2 feet lower than the top of the pool where will the pressure come from? Am I missing something? I wont be using foam.
 
If that's the normal level of the water table there. My personal opinion would be to raise the pool above the water table and build a swale around it. It may not look exactly as you'd like but it'll probably save you a bunch of headache in the future.
 
Bama Rambler said:
If that's the normal level of the water table there. My personal opinion would be to raise the pool above the water table and build a swale around it. It may not look exactly as you'd like but it'll probably save you a bunch of headache in the future.
Click to expand...

I am already raising the pool about 2 1/2 feet out of the ground which is why I am building the retaining wall. In the deep end it will only be about 1 1/2 feet into the water table. I THINK unless the water table comes up level with the top of the water in the pool I should be OK. The only way that could happen is if my whole backyard was 2 1/2 feet under water. We have never had that even with the worst rains in a spring thaw.
 
Some of the pools in my area didn't have any type of drainage for storms or hurricanes so now you see a lot of them with floating liners. The pool builder helping me put rocks and a drain under it with a flex pipe coming out so we can use it in case of heavy storms.
 

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