# Mystery leak



## Plumbus (Aug 4, 2008)

I've been asked to help solve the problem and am open to suggestions:

The leak is still a mystery.
To review what I've done numerous times over the past 8 months:

I've shut off the water at the house several times to check the water service line from meter to house. No leak there.

Then valve back on at the house, so everything inside is wet (ice maker off and valve off at back of house serving backyard irrigation/garage) and, consistently, a leak. Varying from 1.5 gal/hr up to 2.5 gal/hr. Strange that the flow varies.

Then I shut off of the valve going into the water heater; leak drops a bunch: down to .1 to .3 gal/hr.

Turn WH valve back on and start shutting off sink angle stops, shower valves and washing machine: flows vary slightly, but still getting a leak of 1.5 gal or more.
Note: I did replace the washer at leaking faucet at upstairs bath; helped a bit, but leak is still 1.3 to 1.7 gal/hr.

Test today:
with everything on (ice maker off): 1.8 gal/hr., then the next hour it was 1.5 gal/hr.

The mystery continues...


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## ShtRnsdownhill (Jan 13, 2016)

could have an internal leak in boiler or water heater and the water is steaming off? any under ground water lines? RO filter in house?


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## Tango (Jan 13, 2018)

How do you know the gallons lost? Tell how you verify that? Are you sure those main valve closes 100%

Why are you saying there is a leak if everything is dry inside the house or are you hearing sound from the pipe?


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## Alan (Jun 18, 2008)

Tango said:


> How do you know the gallons lost? Tell how you verify that? Are you sure those main valve closes 100%
> 
> Why are you saying there is a leak if everything is dry inside the house or are you hearing sound from the pipe?


Seconding this. 

1.5 gph is a pretty decent leak. To put it in perspective you are looking at nearly 6 cubic inches of water per minute. Probably around 1/3 cup.

Something you should be able to visibly see if you are looking at pipes and fittings anyway.

Sounds like you've eliminated all of the fixtures, so then are you assuming the leak is underground in the house or is there a crawlspace?


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## Venomthirst (Jun 20, 2018)

Could be a malfunctioning trap seal primer somewhere... had one of those not to long ago just steady water flowing through it... maybe a humidifer for the furnace as well... just a guess good luck on mystery leak


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## canuck92 (Apr 1, 2016)

Could be a broken water main , seen that befour. Is there an unusuall amount of water going to sump pit ?


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## The Dane (Feb 19, 2015)

I was going to suggest a humidifier on the furnace continuously running I am sure that would be a lot of humidity in the house and people would have noticed that humidity. I second checking the water flow to the sump pump. I think you wrote that you shut off the water to the water heater and there was almost no leak after that which means it should probably be on a hot water line. I have not seen trap seal primer in a residential house and I have not seen one on a hot water line the phone so I would not suspect that is the case but the water has to go somewhere so either in the drain or evaporation or in the ground. If it goes in the ground you should notice in a sump pit if evaporates that much water would be noticed in very high humidity in the house

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## OpenSights (Mar 23, 2015)

I’ve worked in SD, 90% slab. 9.9% crawl and a few basements in IB.

If it’s a slab and water is underground, my bet is underground. Seen a hot leak once. New home owner though she had in floor heat in the kitchen until she got the water bill.


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## JohnnieSqueeze (Mar 23, 2016)

OpenSights said:


> I’ve worked in SD, 90% slab. 9.9% crawl and a few basements in IB.
> 
> If it’s a slab and water is underground, my bet is underground. Seen a hot leak once. New home owner though she had in floor heat in the kitchen until she got the water bill.




thinking the most he limited the leak was when he closed the hwt valve. Thats probably a 3/4 line. So maybe its in the slab, and between the main and hwt. Why not close the main at meter and fire some air in there. pump 60psi or so? So Cal pressure and see what happens. 


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## OpenSights (Mar 23, 2015)

I don’t remember the company name, but we used a company that specialized in leak detection and line location. 

The company I worked for were hack masters. Two weeks of training and you were on your own. We had a jetter, camera... which you had to rent. I lasted a year, but the general turnover was about 1-2 months.


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## 89plumbum (May 14, 2011)

Plumbus, did you physically see where the T&P drains?


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## Plumbus (Aug 4, 2008)

No slab, just crawl space w/o any noticeable water accumulation or stains.
T & P drain is visible and dry. No humidifier on furnace. No drywall stains or dampness. He is tracking the leak with meter readings.


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## Logtec (Jun 3, 2018)

Sometimes, the FD’s trap is primed from the laundry tub faucet, depending on the faucet, if the “ “hot” water washer isn’t holding the water runs passed the washer and down the TSP tube instead of water is dripping from the faucet due to gravity. In this case you’ll hear a slight hissing sound at the faucet and the pipe/tube/faucet will feel hot.


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## Logtec (Jun 3, 2018)

Also, if it seems to be linked to the hot water, go to the house after no fixtures have been used for an hour or so, then go around and feel the pipes, the hot water pipes should be cold if they haven’t been used. So if there is one pipe that is warm/hot to the touch then that’s a good starting point to trace the leak.


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## Alan (Jun 18, 2008)

I've seen electronic meters measure usage with city and customer valve both in off position.

Sounds like you were able to get the thing to stop moving when you shut off the house though?


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## Plumbus (Aug 4, 2008)

No primer.
He's gone around after shut down and checked for heat in the pipes.


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## PLUMBER_BILL (Oct 23, 2009)

Plumbus said:


> No primer.
> He's gone around after shut down and checked for heat in the pipes.


In my 50 some years as a service plumber, I had 3 mystry leaks.

One was a leaking boiler -- leaking on the top of the boiler. Just a pin hole. but the leak was being dried up by the heat of the boiler no sign of water at all but water had to be added to the boiler every day. No auto fill!

2nd one was a no hot water call. Relief valve run to concealed drain stand pipe in wall. Relief valve was a watts 520 with a fuseable plug running wide open. Could hear water running just could not see it. 

3rd was an Apirl/Air humidifer hooked to hot water running all the time. No visable sign of water, condensate lines ran to sewer. Owner complained 
very high electric bills. W/H making hot water continously


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## Tommy plumber (Feb 19, 2010)

Plumbus said:


> No primer.
> He's gone around after shut down and checked for heat in the pipes.
















Isolate the leak to either the hot or cold. The W/H valve MUST close 100% for this test.


Shut that valve off and with gauges on the laundry hose spigots, you'll know in short order if it is a hot or cold leak. That is a starting point when I do slab leaks after I determine whether or not the leak is outside or inside the footprint of the building.


Then go from there. Unless you already did this.


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## justme (Jul 4, 2012)

I'm sure you have dropped dye tabs in the toilet tanks to confirm no slow leakers there right?


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## Plumbus (Aug 4, 2008)

He's monitored the tanks, but he hasn't used dye.


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## Raleigh Plumbin (May 1, 2009)

Have you pulled a CO to see if you hear water trickling down the sewer line? Have you dye tested the toilets and checked for the ballcock siphoning into the toilets overflow tube?


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## Dpeckplb (Sep 20, 2013)

Tanked or tankless water heater? I had a Navian that must've had a crack in the heat exchanger. I looked for the leak for 2 hours. after two hours I pulled the condensate tube just for giggles and it was giving a stream of water down the condensate.


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