My mother bought a home in North Carolina and built in 1994. She is noticing a large area 24" of wet carpet(wall to wall). The house was built on a slab. She is 75yrs old and is not sure who to call first or how serious this could be. Her hot water heater is gas and there are no signs of leakage near the water heater.She has put towels to absorb the water but it is not helping. What is the likely problem?

You could shut off cold water, see if it stops, shut off hot water , see if it stops, it may be quicker, faster, cheaper if rerouted.
Finding the problem is the first step.

Shut off everything in the home but keep the main open, does the small white triangle pointer on the meter still move? Only good if you are not on a well and are on city water

You already know that you have a leak. The meter's running or the pump gage's dropping.
So now you have to pin point it;.You can't go by the wet spots because water, like electricity, will seek the path of least resistance. This means that the leak can be in one spot and the hot spot some distance away.
I live in a area where all out buildings are on slabs so I've had this many times. Our usual way is to call in a leak detection service such as Sleuth. They will detect the exact position of the leak. Take up the slab, bag the dirt and bare the leak. All we have to do is drain the system, replacethe bad piece of pipe and patch the slab.
Another method would be if the plumber knew the exact pipe that was leaking the fixture it serviced and the location of the manifold that supplied it he could cut the line at the manifold, cap it off and look a new line up in the attic and drop down through the wall to pick up the fixture. Good luck, Tom

Some plumbers may be able to find the leak. Make sure that they have their own equipment and do a number of slab leak jobs. A leak detection company will find the leak within a few inches, and will guarantee the results. Because leak detection is their specialty, they will often be right on top of the leak so that the certified plumber you use for the repair will be able to make a small hole to repair the leak. (http://www.unitedleak.com/link_page2.html)

Some plumbers may be able to find the leak. The problem with that statement is that the actual leak may be some distance from the wet spot. Water, like electricity , will always seek the path of least resistance. If the plumber has his own leak detector so much the better but you must first locate it.

they have their own equipment and do a number of slab leak jobs.
This statement is plumb off the wall. Of course plumbers in a area that have slab homes, such as mine, both have the equipment and the "know how" to deal with slab leaks. Good luck, Tom

Agree, first call a service man with Leak Detection equipment. He will tell you IF you have an under slab leak and WHERE the leak is. Than, proceed with getting few estimates from local plumbers.

BTW: your home insurance company should cover this repair. Most of the time Insurance companies refer you to their "own" technicians to locate and repair the leak.

Many plumbers in the Midwest work to find their own leaks, and apparently Tom disagrees that hiring a plumber who has quality leak equipment and does the leak detection and location in-house rather than to subcontract it out is a bad ideaper his first argument. Leak detection companies do get numerous calls from homeowners and plumbers who have made a hole in the slab only to find that the leak is NOT there. Certainly as a leak detecion company, I would like you to call us regardless, but some plumbers ARE qualified to find leaks and some may mot be, and may not tell you that they are subcontracting the leak detection. The minor implied point that Tom chooses to argue is the difference between leak detection and leak location. Anyone can detect a leak. Some plumbers can LOCATE a leak. And all "leak detection companies" can locate leaks also. Further, many plumbers all over the country know how to deal with slab leaks. Many call a leak detection company. Tom prefers Sleuth although they do not work in your area. I prefer to recommend United Leak Detection. I did not realize that suggesting questioning a plumbers credentials to locate and repair slab leaks was "plumb off the wall" but having seen the way some plumbers operate, contrary to Tom, it seems nothing short of prudent. Rather like checking to make sure your plumber is properly certified. By the way, I strongly recommend that as well. Please please please check to make sure you know who is working in your home and whether your plumber is doing the work or contracting it out. To suggest doing anything less is irresponsible.

Also, in general, a call to a leak detection company can help you determine if you have a slab leak. That part should be a no charge over the phone. They can then locate exactly your leak. I appreciate the "have a leak guy come out first" mentality, but some will come out and charge you the "leak guy premium" even if you don't need them. It is fairly clear in this case, but a free phone call rather than a visit could tell even more. Thanks Tom and Milo, quality plumbers are great to work with, and unfortunately, not all are as helpful."plumb off the wall" to suggest checking the credentials of a plumber who will do the location and repair? Not by a long shot.

Many plumbers in the Midwest work to find their own leaks, and apparently Tom disagrees that hiring a plumber who has quality leak equipment and does the leak detection and location in-house rather than to subcontract it out is a bad idea
Not what I said at all. I don'tb disagree with that statement at all.
What I disagreed with was ;
Some plumbers may be able to find the leak.
No mentionb of having leak detecter equipment here is there? Back when I was out running calls none of the shops had their own equipment and we depended upon Sluth to lkocate, open up the slan aqnd dig down to the leak and bag the dirt. Of course if the plumbing company has the equipment to ndo the jobb it would be redundent to hire another company.

they have their own equipment and do a number of slab leak jobs. That statement was "off the wall" and here's why. I live in a area where all our buildings are on a slab. To assume that a licensed Plumbing Company wouldn't have the correct equipment to repair a leak and then to suggest that living in a area with nothing but slab homes that we didn't have ecpereience enough is not only "off the wall" but downright insulting. My iold company,( 40 men,shop) still uses a leak detection service to pin point slab leaks.
I agree with most of what you've said. You make valid points. I simply took what you posted as it was put down and not as what you intended to say. Hey! I agree with the bulk of your post and if you would fleshed out your first statement a bit I would have agreed to that also. Let's not have hurt feelings over this. Regards, Tom

Quoting :

They have their own equipment and do a number of slab leak jobs.

That statement was "off the wall" and here's why. I live in a area where all our buildings are on a slab. To assume that a licensed Plumbing Company wouldn't have the correct equipment to repair a leak and then to suggest that living in a area with nothing but slab homes that we didn't have ecpereience enough is not only "off the wall" but downright insulting.

I was answering the post, not responding to where you live. North Carolina has many homes both with and without slabs. Further, vouching for all plumbing companies in Florida seems overly confident in the reality of the business to verging on dangerous. I know of numerous plumbers who claim to provide leak detection services only to subcontract the work, or who have equipment, but do so few jobs they are not terribky good at locating sub-slab leaks.

Please check with a leak detection company first, is my answer. If your call is to a plumber, make sure that they are doing the work themselves, and are competent to locate the leak. Unfortunately, the reality of our world, contrary to the blanket trust placed in ALL Florida plumbers by some, you should make sure that you are getting not only what you need, but that the contractors that you hire are being straightforward with you, and that you know who is coming to your home to do work. You can hire the plumber, and your own leak detection company. Further, when I state that, "some plumbers may be able to find the leak", a reasonably prudent person would read that to mean "a plumber may be able to locate where the pipe is leaking water." I don't mean to insult you, Tom, but I don't mind doing so to the potentially hundreds of incompetent contractors out there in the world operating without the knowledge base they will need to properly locate and repair a slab leak, hypothetically in North Carolina.

when I state that, "some plumbers may be able to find the leak", a reasonably prudent person would read that to mean "a plumber may be able to locate where the pipe is leaking water."
Gee! I apologize for taking your statement literately and not attempting to figure out exactly what you really meant to say. My bad! I don't speak for all Florida plumbers but having worked projects from Tampa to Fort Myers I kind of get a frrl for them. The statement I challenged,
Some plumbers may be able to find the leak. sounded like a plumber couldwalk right in and pin-point a slab leak without leak detection equipment and that just isn't so. As I've stated, " water will seek the path of least resistance ". My fault if I misunderstood. However for the most part you and I are on the same page. I think this thread has run its course. Chers, Tom

You are still da man, Tom.

You are still da man, Tom.

Nah! I don't see it that way. I feel that it's you younger guys who have carried me for all these years. I've been retired for over 20 years and I depend on you guys to keep me up on what's new in the trades. It's you guys that make AMHD what it is today and I salute every one of you for your service and dedication. The only reason AMHD still keeps me around is that I've been here so long I'm part of the woodwork. Thanks for the complimen unitedleak but it would be better directed at the members on this page that do all the real work. Regards, Tom

I as well as many others certinaly appreciate your input and the work that you put into answering all of these questions. You make the site accessible in almost real time. Thanks!