Pool drained over winter

[Poolfused]

I have a concrete pool that has lost a lot of water over the winter. Over 3/4 of it. The cover is still on (barely) and I could use some help with getting a plan ready when I take the cover off. I’m going to assume the leak is in one of the floor drains. Water level seems to have stabilized. Any help is appreciated.

 

[Texas Splash]

Welcome to TFP! It sounds as though a drain, or hydrostatic valve in the drain, may be the culprit. As soon as you can pull the cover off and inspect the drain and/or HS valves the better so you can make the required repairs and refill.

 

[Poolfused]

Welcome to TFP! It sounds as though a drain, or hydrostatic valve in the drain, may be the culprit. As soon as you can pull the cover off and inspect the drain and/or HS valves the better so you can make the required repairs and refill.

Thanks for the quick response. So look for cracks or could it be something less obvious.

 

[Poolfused]

Thanks for the quick reply. So look for cracks or would it be something less obvious?

 

[Texas Splash]

So look for cracks or would it be something less obvious?

If you can get in there and still see through the remaining water, try some food coloring. See if it gets pulled down & out. You might have a defect in the drain or line itself which may not be visible to the eye. Or perhaps the HS valve was working as intended to relieve pressure from below and some tiny debris got stuck preventing the valve from closing back down fully. HS valves can also simply go back over time.

 

[Poolfused]

Cool. I have a dye kit. I know the drain cover got kicked off at some point. So leaves or other junk down there could cause this?

 

[Texas Splash]

So leaves or other junk down there could cause this?

If the HS valve was actuated (upwards) to relieve pressure .... yes.

 

[cowboycasey]

The water level will stop at the leak or just below the leak... Has it stopped dropping?

 

[Poolfused]

I just had a chance to remove the cover. The water level stopped about 2 feet above the high drain. It’s an old Sylvan. I’ve attached some pics. The pictures show the water level and the high drain. Note the dirt in the drain. It looks like the pea gravel and clay for the concrete base.

 

[Poolfused]

I’ve completely drained the pool now. Again, nothing obviously cracked. The drain plug is plastic and had no silicone tape or anything. I’m guessing my problem is at this drain.

 

[Noreaster]

Looking forward to someone more experienced than I, however i do not see anything there that looks like a hydro relief valve. The dirt/gravel under the drain plug doesnt look soggy like a leak was there. I'm thinking the lines need a pressure test.