Where is the water going? Finding leaks in a slab house.

[JimRB]

A friend at work said their water bill has been out of the norm for more than a few months. Her husband is not inclined to fix or do anything around the house. The water department guy came over and listened for leaks but could not hear anything. Pipe touching faucets and toilets to hear leaks. Kind of like using a stethascope.

So how do you find a leak of maybe 6-10 gallons an hour when there is no sign of wet spots outside the 1,000-1,500 sf slab house?

I see no clues in the garage where the water heater is set.

I do not see where the water service enters the house. I used to see pressure regulators in the houses I worked on 25 years ago as a tile guy. I also saw main cut offs inside the house. Granted the houses I worked around 25 years ago were "higher end" houses, one might hope a starter house might have a service entrance cut off. Then again it is only 40 feet from the house to the water meter. Where I was going was if there was a cut off inside the house I could turn that off to see if it is the water line feeding the house. Yard is also messy around the house so I can't see anything. It might take an hour to move junk and run an old fashion rake.

I think it is PEX plumbing. I haven't been around houses that do PEX, or I have not paid attention. I haven't done home construction in 20 years. Do they all use distribution manifolds or do they often plumb the way I have done copper or PVC?

This is now a curiousity question more than anything else. They need to get a plumber out that is experienced with how things are done in that neighborhood.

 

[Streetcar]

Typically houses have a shutoff valve as the water enters the house.
Leaks are found by isolating portions of the system until leak is pinpointed with trial and error

 

[Raspy]

First, try to eliminate everything not out of sight that could be the problem. A leaking P&T on the water heater, a leaking flap in the toilet, an outside hose bib, the sprinkler valves, etc etc. Look carefully at everything you can see.

Put a test gauge on a hose bib and turn off the water at the meter to see if there is a pressure drop. This is way more accurate than listening or looking at the meter for movement. If the pressure drops, shut off the toilet angle stops and test again. Then turn off the shutoff at the house, again, and turn off the meter valve to determine if it is leaking in the line from the meter to the house. Do all the tests you can think of to determine if it's actually under the slab or somewhere else.

An underground leak detecting company will put nitrogen and helium into the piping system and listen for bubbling or use a sniffer to get you closer to the problem. Then you can decide if you want to abandon the line or dig and fix.

 

[TheGoose]

Wouldn't the pipes be in the attic? Put a gauge on an outside faucet with an adapter and close the incoming water from the meter. If the pressure gauge drops there is a leak. Put food coloring in the toilets and check the t&p valve on the water heater.

 

[Redlands Okie]

I think Raspy process has a lot of good ideas. Once you get it figured out if its outside or inside the house you can move on to which branch of the plumbing it is with his ideas.

Many times PEX plumbing installed under a concrete floor has a black plastic pipe liner or some such around it. This allows you to cut the end and splice it and pull it thru until you see the new pipe. If its done right you can actually slide a new pipe thru the liner by itself but its usually a bit tougher to do that. Using the old pipe to pull the new pipe or a light rope there is usually best. I think your can coat the PEX with electric wire pulling lube but you best check that to be sure.

If your repair HAS to be in ran in the attic be darn sure to insulate above the new pipe with a really good cover of insulation. Try to set up the insulation to trap heat coming from the heated living spaces below.

P.S. The water meter usually has a small red dial that is shaped like a star, small cog, or triangle shape that will rotate with a very very small amount of water running.

 

[2ndhalf]

I think it is PEX plumbing. I haven't been around houses that do PEX, or I have not paid attention. I haven't done home construction in 20 years. Do they all use distribution manifolds or do they often plumb the way I have done copper or PVC?

This is now a curiousity question more than anything else. They need to get a plumber out that is experienced with how things are done in that neighborhood.

You can use PEX without a manifold. It uses compression type fittings. It is newish to the US but has been used overseas for decades. I used some on a water heater/ whole house filter install. I like it a lot.

I'm wondering if the house, though on a slab, has a footer under the slab and a footer drain. if the water is getting discharged after the meter but before it comes into the house, say around the side of the house, it might go to the footer drain and you would not know it.

 

[gwstang]

If you suspect a leak, all you need to do to check the meter. There should be a small second hand looking device on the meter. Make sure no one in the house is using water at this time. Then watch the little second hand for a minute or two. If it is turning, there is a leak....if not, no leak. "The water department guy came over and listened for leaks but could not hear anything. " He should have look at the meter and determined this. First thing to check.

 

[kenmac]

If you suspect a leak, all you need to do to check the meter. There should be a small second hand looking device on the meter. Make sure no one in the house is using water at this time. Then watch the little second hand for a minute or two. If it is turning, there is a leak....if not, no leak. "The water department guy came over and listened for leaks but could not hear anything. " He should have look at the meter and determined this. First thing to check.

Yep, the water meter is your test point. With nothing on in the home, dial on water meter should not move. If dial moves, shut off all stops on the system and re check. If it's leaking within the slab, it will be impossible to locate.

 

[2ndhalf]

If you suspect a leak, all you need to do to check the meter. There should be a small second hand looking device on the meter. Make sure no one in the house is using water at this time. Then watch the little second hand for a minute or two. If it is turning, there is a leak....if not, no leak. "The water department guy came over and listened for leaks but could not hear anything. " He should have look at the meter and determined this. First thing to check.

I guess I assumed they had already done this or wouldn't know that it was using 6 - 10 gallons an hour. I guess maybe the bill has the gallons on it.. don't know.

 

[Redlands Okie]

Ya most water meters record gallons used fairly accurately. There are business that can usually locate a leak under the slab fairly accurately but their not cheap.
Someone might should check on their homeowners insurance. It will often times take care of problems l like this.