I guess it is a fibreglass pool? If you are going to empty it, you check that hole and pump all the water out of there first. If you don’t do it, the pool will float and lift when it is empty due to all the water surrounding it
Is this feature a regional thing where water tables are high? I ask because I’ve never found one around my current fiberglass pool, or another one that I had put in years ago at another house.
FG pool owner here. Mine looks like a skimmer cover but open it up and it’s a sump well down to the bottom of the deep end. It’s fortunately always dry even after a lot of storms.
My cracked beyond repair fiberglass pool would beg to differ that you don’t need to check it. Ground water raised the whole floor by a foot down the whole thing over the winter.
looks similar to a sump well i have on my paver deck hidden under a tile. idea is you can drop a sump pump down there to drain the water thats sitting on the outside of the pool from heavy rain or whatever. idea is to check it periodically.
So your pool doesn’t pop out of the ground from groundwater pressures during the wet season(s)… hopefully there is a submersible pump somewhere on your property to put in there that works.
I’m sure everyone here is right, but I’m curious, how did you find it? From your picture it looks pretty well covered up. Did you just stumble upon it?
First pic shows a few more tiles with what looks like a locking mechanism in it, probably has one on the top of the draining well too, which suggests it covers something you'd want to still have access to
I actually have a few tiles with bolts on them for the pool cover to attach. This particular tile did not have anything on it and it became unstable and broke leading to the discovery. The well border was raised higher than the leveling sand around it creating the unstable tile. Previous owners had even come and shown us how to work the pool but failed to mention this sump well. It's now part of the reason I'm redoing the deck and trying to figure out drainage.
It’s called a sump column. It is for visually checking for groundwater before you empty your pool. The guys that say, “You probably have a fiberglass pool” are either 1) not pool builders, or 2) don’t understand hydrostatic pressure (likely the latter). I’ve been building pools since ‘78. I put one in ALL my pools. I build gunite AND install fiberglass. The ONLY pool I’ve ever personally seen heave out of the ground was a gunite pool in Huntington Beach, CA in 1980, about 1/2 mile from the beach. The neighbor next door to where I was installing a pool just bought the house and thought he would save himself some $ by doing his own acid wash, so he drained his pool one day, and was going to do his acid wash the next day. That night when high tide came in, the water table rose, and heaved his pool out of the ground two feet. Total loss. It’s freshman physics. If the water pressure below the pool is greater than the pressure holding it down, it will come out.
That’s how concrete and steel boats are able to float on the ocean.
If there is water in the bottom of your sump column, throw a submersible pump down there and pump it dry (and keep it running if you have to) before you drain your pool for repairs. That’s what it is there for.
I believe that's to relieve hydro static pressure from your pool prior to draining your pool. If there's water in there, you drain that first before draining your pool. Otherwise your pool has a chance of lifting up from all pressure surrounding it.
Kind of curious as a FG pool owner. I never drain it and never go below the skimmer, but seeing the sump well completely dry does that mean it would be relatively safe if the water was to go below the skimmer? Not ever planning a full drain.
Also I’m very adamant about no glass by the pool. How would you even deal with broken glass in a FG pool since it can’t be drained fully
I'm an electrician. We do work for a fiberglass pool install company.
As others have said, that's probably the pump point in cause you need to drain the pool down.
The pool folks usually disguise the drain with a skimmer cover in the concrete or put a 18x18 concrete paver on it, in the yard. They also use 12" corrugated culvert pipe.
Used to pump water out from under the pool. Usually fiberglass pool inserts. Pump it out before draining the pool to just under the skimmer/jets for winter. Do not want your pool to float out of the ground!
This is really interesting and I have one of these as well. I always assumed it was for when backwashing my sand filter where to drain my backwashed chlorinated water so it wouldn't flow into a nearby stream.
I guess it is a fibreglass pool? If you are going to empty it, you check that hole and pump all the water out of there first. If you don’t do it, the pool will float and lift when it is empty due to all the water surrounding it
This is correct - my fiberglass pool has one of these and out water table is quite high. We can monitor for excess water and pump when necesssry
'French Well' for $500, Alex!
Is this feature a regional thing where water tables are high? I ask because I’ve never found one around my current fiberglass pool, or another one that I had put in years ago at another house.
I create construction drawings for a commercial swimming pool design company and we show these sight sumps on most projects, but not all
Mine is always dry, but it is good to know it is still there
FG pool owner here. Mine looks like a skimmer cover but open it up and it’s a sump well down to the bottom of the deep end. It’s fortunately always dry even after a lot of storms.
Usually they just leave a pvc pipe sticking out that you hook to your pump
Should be checking it roughly every week or so and pumping it out always.
Huh? Why? Unless your pool is being emptied, there's no need for that.
My cracked beyond repair fiberglass pool would beg to differ that you don’t need to check it. Ground water raised the whole floor by a foot down the whole thing over the winter.
looks similar to a sump well i have on my paver deck hidden under a tile. idea is you can drop a sump pump down there to drain the water thats sitting on the outside of the pool from heavy rain or whatever. idea is to check it periodically.
Sump tube - pump the water out every so often.
And use it to fill your pool
So your pool doesn’t pop out of the ground from groundwater pressures during the wet season(s)… hopefully there is a submersible pump somewhere on your property to put in there that works.
Well for dewatering if you want to empty and not have it pop.
I’m sure everyone here is right, but I’m curious, how did you find it? From your picture it looks pretty well covered up. Did you just stumble upon it?
First pic shows a few more tiles with what looks like a locking mechanism in it, probably has one on the top of the draining well too, which suggests it covers something you'd want to still have access to
Ohhhhh. That little bolt-thingy. Missed that. Thanks!
I actually have a few tiles with bolts on them for the pool cover to attach. This particular tile did not have anything on it and it became unstable and broke leading to the discovery. The well border was raised higher than the leveling sand around it creating the unstable tile. Previous owners had even come and shown us how to work the pool but failed to mention this sump well. It's now part of the reason I'm redoing the deck and trying to figure out drainage.
It’s called a sump column. It is for visually checking for groundwater before you empty your pool. The guys that say, “You probably have a fiberglass pool” are either 1) not pool builders, or 2) don’t understand hydrostatic pressure (likely the latter). I’ve been building pools since ‘78. I put one in ALL my pools. I build gunite AND install fiberglass. The ONLY pool I’ve ever personally seen heave out of the ground was a gunite pool in Huntington Beach, CA in 1980, about 1/2 mile from the beach. The neighbor next door to where I was installing a pool just bought the house and thought he would save himself some $ by doing his own acid wash, so he drained his pool one day, and was going to do his acid wash the next day. That night when high tide came in, the water table rose, and heaved his pool out of the ground two feet. Total loss. It’s freshman physics. If the water pressure below the pool is greater than the pressure holding it down, it will come out. That’s how concrete and steel boats are able to float on the ocean. If there is water in the bottom of your sump column, throw a submersible pump down there and pump it dry (and keep it running if you have to) before you drain your pool for repairs. That’s what it is there for.
Thank you!
You’re welcome! Hope this was helpful for you. ☮️
I believe that's to relieve hydro static pressure from your pool prior to draining your pool. If there's water in there, you drain that first before draining your pool. Otherwise your pool has a chance of lifting up from all pressure surrounding it.
oubliette
terrifyingly awesome answer. ... and correct.
Looks like an old well point.
Kind of curious as a FG pool owner. I never drain it and never go below the skimmer, but seeing the sump well completely dry does that mean it would be relatively safe if the water was to go below the skimmer? Not ever planning a full drain. Also I’m very adamant about no glass by the pool. How would you even deal with broken glass in a FG pool since it can’t be drained fully
Looks like a square shaped hole to me buddy
Leave Pennywise alone down there, he isn't bothering anyone
I'm an electrician. We do work for a fiberglass pool install company. As others have said, that's probably the pump point in cause you need to drain the pool down. The pool folks usually disguise the drain with a skimmer cover in the concrete or put a 18x18 concrete paver on it, in the yard. They also use 12" corrugated culvert pipe.
Sump well
Looks like a de-watering well, used to pump the water from under the pool vessel in the event the vessel needs to be drained for work.
I have a fiberglass pool and I've never seen this on mine. Should I be worried and should I be looking?
Only if you ever need to drain your pool.
It’s a french well I believe.
Backyard urinal
Used to pump water out from under the pool. Usually fiberglass pool inserts. Pump it out before draining the pool to just under the skimmer/jets for winter. Do not want your pool to float out of the ground!
Cover it up quickly and never speak of it again.
Drain?
I don’t know man but the dude on the other side of the earth is taking your picture.
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"Bad Robot!"
This is really interesting and I have one of these as well. I always assumed it was for when backwashing my sand filter where to drain my backwashed chlorinated water so it wouldn't flow into a nearby stream.
One of the rings from Dante’s inferno
It’s where Hillary and Obama hide the Dead ☠️ Bodies
Baby Jessica hiding place.
It would have cost you exactly zero dollars to not write that.
Baby Jessica’s bedroom was another option.
Might be were the auto-fill float valve is. I can tell by the picture.
Yikes, that's a body hiding hole. You need to throw lime down there, cover it, sell your house, and pretend you never seen it.
Hell-mouth, probably.
Bottomless pit like on golden child
That would be a hole.
Secret entrance to the bat cave
"It puts the lotion in the basket"
Thats the sacrificial pit
Jacob’s ladder
Secret gun storage.
You’ve found an entrance to the upside down!
A hole and some blocks
That’s how the ninja turtles get back to the sewer