Phantom leak to waste line

[TX Skydiver]

I have an in ground gunite pool that used to have a DE filter with a push/pull backwash valve. I kept having problems with water leaking to the street via the waste line and assumed it was the backwash valve leaking by. I never fixed it because it was the end of the season and I was planning on switching to a cartridge filter this summer. I installed the cartridge filter last week and began filling my pool back up two days ago after acid washing it. I got about 10,000 gallons into the pool and dumped in some shock and started the pump. Somehow I STILL have water leaking to the street via the waste line even though it has been cut and capped where it used to connect to the old backwash valve. It only leaks when the pump is running, and I'm guessing at a rate of about 2 -3 gpm. Doesn't matter if the valves are set to full pool discharge, full hot tub discharge, etc...

Any ideas?? Thx!

 

[jblizzle]

Welcome to TFP!!!

Any chance you have a overflow pipe installed somewhere that ties into the backwash line? I would be surprised if you do though as the backwash would have pushed back into the pool. Something does not make sense.

BTW, I recommend you take a look at some of Pool School. Dumping in some "shock" is not part of our vocabulary
Try these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool
ShockLevelAndMAINTAIN Process

Please add your pool details to your signature as described HERE as it will help us help you.

 

[TX Skydiver]

Thanks for the welcome!

As far as an overflow pipe, no I do not have one. I agree it makes no sense. It was fine for four years and then started this when I had the DE filter, and now it continues with the new cartridge and no backwash valve. I'm at a total loss as to how I can be pushing water into a pipe that is capped at the filter......just thought maybe I'm missing something

 

[jblizzle]

Can you provide any pictures of the setup? Although I can not imagine how this is still tied to the pool.

 

[JasonLion]

I can think of a couple of possibilities, though some of them seem quite unlikely. The waste line might be broken underground and be sending ground water to the street. The waste line could also be tied into an underground french drain system, and again sending ground water to the street. Or the plumbing might somehow be very different from what you think it is, and the pipe by the street might be completely unrelated to the pipe that was capped off.

 

[jblizzle]

Or how about the pipe to the street and the return line from the pump are next to each other underground and both are cracked
That could explain why you would only see water when the pump is on ... although seems unlikely.

 

[TX Skydiver]

I can take some pics when I get home. I can't imagine either

The set up is pump to filter, filter to heater w/bypass around heater to 3-way valve for pool/spa. The line that was the outlet to waste from the backwash valve is cut and capped at ground level. Pretty simple set up.

- - - Updated - - -
"Or how about the pipe to the street and the return line from the pump are next to each other underground and both are cracked
That could explain why you would only see water when the pump is on ... although seems unlikely."

Well......they are about 4 inches apart where they go into the ground........hmmmmmmmm

- - - Updated - - -
"I can think of a couple of possibilities, though some of them seem quite unlikely. The waste line might be broken underground and be sending ground water to the street. The waste line could also be tied into an underground french drain system, and again sending ground water to the street. Or the plumbing might somehow be very different from what you think it is, and the pipe by the street might be completely unrelated to the pipe that was capped off."

I do have drains on the patio between the house and pool but I have a hole in the ground where they and the back wash pipe end and then another pipe continues to the street from there for all drainage. In the hole where they all come in is where I can see that the water is coming through the old backwash pipe, but only when the pump is running. The pool is only half full as of now as well, I was just testing my filter install while refilling when I found this