Water leaking through overflow drain

poolnovice1

Bronze Supporter
May 11, 2018
142
Houston
My overflow drain exits out to the street curb. And waste (backwash, etc.) goes to the sewer line.

The pool has been at least 1" below the fill line so there should not be any water coming out of the overflow drain.

I contacted a pool guy I've used before. He stopped by and emailed that "It wasn’t leaking from the sight glass on high speed. I don’t think it’s bypassing to waste." That makes sense because any waste would go to the sewer line. But I still have no answer as to why water is coming out of the overflow drain when the pool level has been significantly below the fill line.

Any idea what could be causing this and what to try?
 

JJ_Tex

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Jul 17, 2019
2,681
Prosper, TX (DFW)
Pool Size
13000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
That is the way mine is setup as well, but I also have the drains and gutters tied into that line running to the street. Could yours have more than just the overflow tied to your drain line as well?

You said the water is below the fill line, but where is it in relation to the overflow drain? It is usually a pipe with a grate by the skimmers.
 

poolnovice1

Bronze Supporter
May 11, 2018
142
Houston
That is the way mine is setup as well, but I also have the drains and gutters tied into that line running to the street. Could yours have more than just the overflow tied to your drain line as well?

You said the water is below the fill line, but where is it in relation to the overflow drain? It is usually a pipe with a grate by the skimmers.
I do have drains and gutters tied to it. However, we have not had rain in a few days. I've been seeing water along the curb for at least a month now.

It has been well below the overflow drain. There's no way any pool water has been getting into there.
 

JJ_Tex

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Bronze Supporter
Jul 17, 2019
2,681
Prosper, TX (DFW)
Pool Size
13000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Maybe a leaking sprinkler that is getting picked up by one of the drains?

How much water is coming out? One thought is to try to test the water to see if it is chlorinated coming out of the pipe. I doubt you can get enough for a drop test, but maybe a test strip would register?
 

poolnovice1

Bronze Supporter
May 11, 2018
142
Houston
The drains are clear and dry. There are no sprinklers near the drains.

It's a small trickle. I just tried testing it and I didn't detect any chlorine in it but I will try later further up the pipe. The end of the pipe has a ton of algae so maybe that could have used up any chlorine.
 

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JJ_Tex

Gold Supporter
Bronze Supporter
Jul 17, 2019
2,681
Prosper, TX (DFW)
Pool Size
13000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Not sure but that is a lot of algae in the pipe. My guess is that it is not coming from a chlorinated pool.

Have you tried snaking out the pipe to see if maybe you have water backing up somewhere that is getting trapped and slowly working its way through the drain?

Anyone else have ideas?
 
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Burke_B

Well-known member
Apr 20, 2022
61
San Antonio, TX
Pool Size
13700
Surface
Plaster
Chlorine
Liquid Chlorine
This is likely a long shot but, without knowing your lot/house set up in relation to that drain and everything in close proximity, it might be worth looking. Have you confirmed that you don't have a water leak in your house system that is somehow making it to that drain pipe? Sometime when you know there is no water running, filling a hot water heater, water softener, etc..., lift your meter cover and see if the wheel is spinning. Not trying to insult your intelligence with those instructions....just offering something that might be worth ruling out and is fairly easy to accomplish.
 

Newdude

Mod Squad
Gold Supporter
TFP Guide
Jun 16, 2019
17,263
NY
Where does your central AC drain ? Mine leaves the attic and hits a gutter. I don't live 250 miles south of Heck and I have a trickle coming from my gutters. I can only imagine yours.
 
Jul 19, 2022
13
CA, USA
I am having the exact same issue as the OP. I have an autofill valve but the water is 1 inch below the overflow. We've dropped the pool level about an inch after we noticed it continuously ran at low pressure, but it seems to just be due to evaporation. Regardless, I am very confused at why water is being discharged into the street. It seems to happen in the morning based on it being puddled in the street but dry by the actual waste pipe by afternoon when we discover it. My hunch is its when the pump first turns on, but I am confused still. Anyways, I hope the smart people on this forum can help OP out as well as us other confused folks.
 

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poolnovice1

Bronze Supporter
May 11, 2018
142
Houston
Not sure but that is a lot of algae in the pipe. My guess is that it is not coming from a chlorinated pool.

Have you tried snaking out the pipe to see if maybe you have water backing up somewhere that is getting trapped and slowly working its way through the drain?

Anyone else have ideas?

An alternate theory is that I have a leak somewhere else that's finding its way into the drain pipe through a crack in the PVC.

I've shut off my irrigation system and I'll see if that helps. After that I'll try shutting off the pool equipment for a day or two but I don't think any of my pool equipment is hooked up to that line.

If none of that works, I'll have a plumber put a camera through it and see if we can find anything.

What a strange issue.
 

poolnovice1

Bronze Supporter
May 11, 2018
142
Houston
Where does your central AC drain ? Mine leaves the attic and hits a gutter. I don't live 250 miles south of Heck and I have a trickle coming from my gutters. I can only imagine yours.
You might be onto something here.

This gutter's downspout drains into the overflow pipe and I see standing water here. While it did rain for about 10 minutes a few days ago, I would think that the 100+ degree temps would have evaporated it by now.

PXL_20220726_160430270.jpg
 
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Bperry

Gold Supporter
Aug 20, 2020
2,055
Knoxville, TN
Pool Size
27000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-60
You might be onto something here.

This gutter's downspout drains into the overflow pipe and I see standing water here. While it did rain for about 10 minutes a few days ago, I would think that the 100+ degree temps would have evaporated it by now.

View attachment 440343
If you’re in Houston, it’s humid enough that water doesn’t evaporate all that fast compared to other places without deathly high humidity. ;)