fiberglass pool appears to be leaking

[gwtw]

I am having to add water to my pool daily to keep the water level half way up the skimmer. I did a bucket test for 24 hours, running my pool normally, and I lost approximately 1/2" of water total. (With the pump on 12 hours during the day, I lost about 1/4" and with the pump off 12 hours at night, I lost another 1/4." I lost about 1/8" inside the bucket to evaporation with the pump on, and nothing to evaporation with the pump off since it was at night.) I checked the pool equipment during the bucket test, and noticed that the ground around the pump stays wet when the pump is off, but the ground stays dry when the pump is running. If I put my hand underneath the pump when it is off, I can feel it slowly drip, but I don't feel any water coming out when it is running. After being off for 12 hours, the ground around the pump was pretty wet but there were no puddles. I see no bubbles in the pump basket or out of the returns when the pump is running so it appears to be working normally. I was told by a pool pro that it sounds like the seal in the pump could be leaking, which wouldn't surprise me since this is an older pump. Could this be the source of my leak, even though I'm experiencing a little bit of water loss with the pump running and I see no evidence of any leaking around the pump when it runs? Or does it sound like there could be a leak in the shell of the pool somewhere since I lose about the same amount of water with the pump on as with the pump off? I checked the backwash line and I'm not losing any water out there right now, so the only place I see any evidence of leaking around the equipment end is around the pump but only when it is off. I realize that 1/2" a day isn't a significant amount, but it concerns me because I know that leaks can cause problems if they aren't fixed in a timely manner.

 

[Texas Splash]

Potential leaks are good reason for concern. I doubt the shell itself is the cause, but if you were concerned, you could plug all ports going into and out of the pool (jets, skimmer, drain, etc) and let it sit with system off overnight to verify. A minor drip from the pump wouldn't seem to account for a large amount of water loss. High winds and heat really take a lot of water from us though. Even with the bucket test, the bucket is shielded from the wind that our larger pool surface is subjected to. Your statement about the ground being dry when the pump is on, but seems to be more wet when off would point towards something on the suction side before the pump. If you had a leak after the pump & filter, there's no doubt with the pump running and pressurized water lines you'd have a mess. When the system is off however, water can slowly seep out of a suction line. So that may be an area you might want to pay a little more attention to. At some point consider a pressure test if possible to see if it's holding okay.

 

[gwtw]

Thanks for responding. I have read information on this site and others about suction side leaks and I'm not showing any signs of a suction side leak since there are no bubbles coming out my returns or in my pump basket and my pump is operating normally. I had a leak in my multiport valve a few weeks ago which caused water to leak out my backwash line but a new valve has been installed and the ground around the backwash line appears to be dry now. The only leaks that I'm seeing around my equipment is underneath my pump but only when the pump is off. My pool equipment is slightly downhill from my pool, so would it be possible to lose 1/2" of water a day if the pump was leaking when the pump is off? It looks like my pool leaks a little bit when the pump is on too, but I can't get my lines pressure tested unless I hire an expensive leak detection company two hours away to come over here.

 

[Texas Splash]

Based on your additional info, I would look into the pump a bit more. If a seal is starting to fail, pressure could be trying to seep from there when the system is off as well. Depending on the model of your pump motor, you might consider replacing the seal(s). You can contact many of the online supply sources who offer "Go-Kits" and assorted seals that will match your pump motor and where it mates to the wet end.

 

[sktn77a]

1/2" a day is almost 100 gallons! You'd surely see it if it was leaking from the equipment pad. Do what TexasSplash suggested - plug all the inlets and the skimmer and see if you still lose water.