Opening hydrostatic valve to prevent pool popping

pdo001

New member
Jan 14, 2020
2
Annapolis, MD
Hi all,

New to the forum. I have an inground concrete pool. The pool was left unkept and it turned into a swamp by the time I got it. So I drained it to facilitate cleaning. My friend cautioned me about pools popping if ground water rises. So he said open the hydrostatic valve to relieve any pressure that may build and leave it open. He showed me the 1.5 in opening I needed to unscrew. However, when I unscrewed it, it was just a cap and wasn't any sort of valve. The water didn't drain or anything. The pipe goes down about 2ft and then I hit something hard. Looks like there's a bunch of mud underneath the water. So I can't really see if there's something else all the way down there. Anybody know if there's something else down there that needs to be somehow opened?
 

PoolGate

Gold Supporter
TFP Guide
Jun 7, 2017
4,133
Damascus, MD
The underside should just be opened to the ground. If water comes up, it will seep into the pool via that hole. If you shove a stick in there does it come back muddy/dirty? Can you shine a flashlight in there?

On mine they are not "valves" they are just holes that must be manually unscrewed.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,958
Pleasanton, CA
A hydro-static valve should open on it's own when the pressure below the pool exceeds that of the pressure in the pool. However, you may not have a hydro-static valve. They are not installed in every pool. But you should be able to install one if so desired.
 

pdo001

New member
Jan 14, 2020
2
Annapolis, MD
The underside should just be opened to the ground. If water comes up, it will seep into the pool via that hole. If you shove a stick in there does it come back muddy/dirty? Can you shine a flashlight in there?

On mine they are not "valves" they are just holes that must be manually unscrewed.
The underside should just be opened to the ground. If water comes up, it will seep into the pool via that hole. If you shove a stick in there does it come back muddy/dirty? Can you shine a flashlight in there?

On mine they are not "valves" they are just holes that must be manually unscrewed.
Thanks for the input. I shoved a stick down there and it was muddy. I rigged an extension to my shop vac and sucked out most of the water and shined a light down there. It just looks like mud. So, I guess I should be ok having it open to prevent pool popping while I work on cleaning the pool. Thanks everyone for the responses!
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
892
Spring Valley, NY
I wouldn't leave the pool empty this time of the year for too long as water table tends to be higher now. Lots of inward pressure without water can't be a good condition.