Slab leak on outer wall - questions?

[John972-]

We have a slab leak. We discovered the leak when the kitchen hot water spout turned hot immediately when turning it on and it's the farthest water source from the hot water heater (about 40 ft.). It had NEVER done that before. No other water source in the house, even those much closer to the water heater does this.

We further corroborated the leak by checking the water meter which still moved slowly when no water was demanded. When we turn off the hot water heater valve, the outside meter does not move.

A leak detector company could not find the leak saying it was due to the type of floor that we have. Our home was built about 55 years ago in the north Dallas area and it's on a slab with what's called a California floor. This is a sub floor of about 4 inches above the slab.

We dug a hole on the side of the house and sure nuff when we turn on the hot water, water starts entering the hole but there are no visible leaks in the exposed pipes we found below the foundation and water seems to be coming from where the pipes enter the foundation's concrete.

Our questions are:
What is the usual procedure a plumber would employ to fix this problem?
First: How would he find out the exact spot where the leak was if there is a way?
Second: Would he dig out the concrete, replace the lines, and then replace the concrete and would the digging be done under the foundation or on the side of it?
Would it be possible to access the pipe through the side of the foundation and do some kind of re-routing of the pipes?

We have not had hot water in about a month. Cold weather has delayed the digging of the hole.

We greatly appreciate any help, experience, or information anyone can give on this situation.

 

[phishfood]

I would drill a hole through the bottom of the cabinet, then through the concrete slab, put a new section of pipe in to supply the kitchen faucet, and re attach it to the existing piping under the slab.

And then, depending on the situation, I might recommend a complete repipe.

 

[John972-]

Thank you phishfood for your response. I do appreciate it.

We don't have a lot of working room under the sink, although it is a double cabinet area, so would you remove the kitchen sink for more space?

And, what kind of drill would you use to go through the slab?

Thank you for any suggestions here.

 

[phishfood]

That will require a hammer drill or rotary hammer with a masonry bit.
How much room you will need will depend on the overall length of the drill and bit. The bit length will need to be long enough to reach through the bottom of the cabinet and then completely through the concrete. Standard thickness for interior concrete is usually 4", but this can vary widely.

 

[johnjh2o]

Keep in mind that all the water lines under the slab are the same age and most likely in the same condition. Even if you locate and repair the existing leak there is a good chance that others may follow. As fishfood said it may be time consider a re-pipe.

 

[John972-]

Thank you phishfood and johnjh20

We are going to try to repair it and for now, hope for the best. We are going to take your advice and try to go through the cabinet, through the slab and connect to the line below. Since we have a hole dug and have found the pipes, a big part of the repair labor is done, hopefully.

With a concrete slab what is involved in a repipe? If we go with copper, do we have to re-route the water line around the outside of the house? With 5 water intake lines, all near the perimeter except the W/D in the garage which isn't to far from an outer wall, and a 1500 sq ft house, is there any way to approximate the cost of a repipe?

Thanks again for your help. I feel like you are our lifeline.