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

[JimRB]

I thought about borrowing the key from my parents. It sure would knock the water bill down as they are out of the house close to 12 hours a day.

 

[Boiler74]

A thermal camera might show the general area of the leak. I have a FLIR camera that attaches to my iPhone/iPad and it is pretty sensitive. Some larger cities rental companies rent them I hear. Anyway, if you have a hot water leak it will show red. A cold water leak will be a bit more tricky. I would shut the water off of a day or so..... let the leak stop and then water that has leaked out normalize to the surrounding temps under the slab. Then turn it back on. The leak should show colder or hotter on the thermal camera and give you a general idea of where it is if under the slab. I say "should" and "might" because I'm just theorizing here. But it will show footprints and hand prints for a long time on surfaces, so I think it would show temp differences due to the water leak. Hope that helps.

 

[Larry Caldwell]

"Water supply lines are never installed below the slab"? Huh? It's very common.

Maybe an amateur would do it, but no professional builder would. ADS drain lines go under the slab, water supply of any kind does not.

 

[Raspy]

Maybe an amateur would do it, but no professional builder would. ADS drain lines go under the slab, water supply of any kind does not.

No professional would do it? I'm impressed that you know what no professional would do, but it's just not the case. In the hundreds of slab homes I've worked on they have all had water pipes under them and even the new ones being done right now have them. All of those homes were built by "professionals". Maybe a bit more research before you get so adamant would be good.

Cold lines are run in type L copper and either insulated or run in plastic sleeves. Hots are insulated. All underground copper joints are silver soldered. Now, various kinds of plastic lines are going in. Maybe you could tell us how professionals run water to kitchen island sinks if it can't go under the slab. Or in cold climates where we don't want pipes in the attic or outside walls, how we get water to interior bathrooms, etc. I'm on the edge of my seat with this one.

I ran lots of them under my new house and the inspector was fine with it. They were in PEX, black poly and copper, depending on the situation.

Radiant supply and return lines are also run there if it's convenient.

Not sure what "ADS" is, but I guess it must need draining. :laughing:

 

[newbury]

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?
<snip>

Sound is the most often used.
Sometimes one might use air but if you only have a 40 foot run it should be easy to find outside.
Google "underground water leaks stethoscope". But basically take a length of PVC pipe, tape a Styrofoam cup over the top, fasten a listening device to the top (stethoscope, Telephone Microphone Suction Cup Pickup).

I thought about borrowing the key from my parents. It sure would knock the water bill down as they are out of the house close to 12 hours a day.

I've been turning my water off before the meter for a couple of days at a time due to a leak, and investigating on how to find a leak.

We left our Mississippi house empty since May. The house is about 120 yards from the main and there's a spur of about the same off to my workshop.

SWMBO went to stay with her mom (she's an Attorney handling a complicated will settlement, I had to be in Virginia for construction of an addition). The water bill was about $150 for June. I got SWMBO to turn off the water. We came back about the 19th of Nov, turned on the water, it was running about 1000 gallons a day compared to normal usage over the years of about 60 to 100 gallons per day (just the two of us).
So until we get a plumber out here I fill buckets for usage and turn the water off for most of the days. Today was fill up, laundry, bath day and the water was turned on for 8 hours and about 300 gallons, which translates into about $2 I think.

Water supply lines are never installed below the slab for exactly that reason. If there is a leak it's either a fixture like a leaking toilet, or it's in the line between the meter and the house. A leak inside the house would mean wet walls or ceiling.

I've a water line under the slab for my workshops. NEVER should rarely be used.

JimRB - it reads like your trying to help a friend with a sticky domestic situation. Good luck but they should expect to need a plumber and big bills.

 

[kenmac]

Maybe an amateur would do it, but no professional builder would. ADS drain lines go under the slab, water supply of any kind does not.

LOL. You must haven't ventured out very far from where you live.. There are many homes with water lines , and gas lines that were installed in slab homes yrs ago..
Being professional has nothing to do with it.. that's the way it was done yrs go. Many yrs ago, (around here) they installed gas meters in a crawl space ,or inside the homes.
They now use pex in slabs around here.
there are also radiant heating systems where pex is used under the slab , instead of your normal type heating system

 

[dadster4]

Maybe an amateur would do it, but no professional builder would. ADS drain lines go under the slab, water supply of any kind does not.

I worked on more than 50 jobsites installing both metal and pvc round duct under concrete slabs...had to coordinate with the plumbers to avoid conflicts with his pvc drain lines and copper water lines. Electrician's conduit went in after 4" of pea gravel, then a vapor barrier and 4" of concrete. You may want to check out a construction site with housing on a slab...learn something new :drink:

 

[Raspy]

I worked on more than 50 jobsites installing both metal and pvc round duct under concrete slabs...had to coordinate with the plumbers to avoid conflicts with his pvc drain lines and copper water lines. Electrician's conduit went in after 4" of pea gravel, then a vapor barrier and 4" of concrete. You may want to check out a construction site with housing on a slab...learn something new :drink:

Maybe they weren't being built by "professionals"

 

[rustyshakelford]

Maybe they weren't being built by "professionals"

Man he got you spun up. He's the professional at doing that!

Check me off for having my water line thru the slab for our island kitchen sink and dish washer.

No probes but it's only been 2 years

Brett

 

[kenmac]

Man he got you spun up. He's the professional at doing that!

Check me off for having my water line thru the slab for our island kitchen sink and dish washer.

No probes but it's only been 2 years

Brett

A professional plumber would have never installed your water line in a slab. You must have hired a hack !:laughing: LOL