locating galvinized pipe in slab

I'm hoping someone here can help me. My house has an addition that was done in the 70' or 80's and instead of building it at the same level as the original part of the house, they lowered it and put it on a slab. I had a hot water leak a couple years ago and had to destroy the old shower enclosure to get to the slab where it was leaking. I was planning on adding a second kitchen anyway, so decided to remodel the bath at the same time since it was now torn up. I found the old hot water pipe under the old part of the house (foundation) and cut and capped it. I then ran an entire new supply line to the newer part of the house and added a second water heater etc. Trouble is, I could never find the cold water supply going to the "new" side of the house. It wasn't leaking or anything so simply capped it at the first place it came up, behind the toilet and completer the remodel. WELL.... now it's developed a leak too! It's a tiny leak, but has ruined the drywall. I've torn out the wet drywall to expose the pipe and it's only about 2 " sticking out of the wall/slab. The water seems to be coming up through the slab. I once again went under the crawl space in the old half of the house and still can't find the line but it HAS to be coming from that original side. Is there a way to trace the line so I can cut it off at the source? One would think it would be close to the old hot pipe but NOT. Am I going to have to tear up the tile and break up the slab to get to it? Even then, if I can't find the source and cut it off there, it's just going to develop another leak later.

There electronic locaters.but you have to call a plumbing contracter that
has this equipment.And it is not cheep

Sounds like the original house is over a crawl space?

Find where the water is coming into the house. If you have galvanized piping, it's probably time to replace it with copper or pex or something else anyways. Map out where there are sinks, etc. in the house. There's probably a T somewhere that is running to the new location, and feeding the local fixture. Is the house in an area that freezes? the pipes would need to be protected. It could be that that section gets the supply through the wall, then it runs down into the slab from the joining wall.

Yes, the original house is foundation built. I can find where the supply comes into the original house and where all the bathrooms, kitchen, laundry etc are. The only pipes I can find going to the "new" side are the black gas pipe and the hot water pipe I disconnected last year. All the plumbing in the original house is on the north side and the bathroom in the new side of the house is smack dab in the middle of it. The new kitchen is between the old side of the house and the bathroom with the problem and that room appears to have been a patio that was enclosed at some point to be just a big unfinished room. Previous owner started the remodel so the kitchen sink and cabinets were in but not plumbed (who would set cabinets before plumbing?)

To make matters worse, the remodeled kitchen had an uneven slab that we poured tons of new concrete over to level and then tiled. It's really nice and I am visualizing jackhammering all that concrete to get to this silly pipe if it's buried in the original slab. This house is so crazy that the pipe could actually be routed ANYWHERE. At least I've made drawings and have pictures of everything we've done.

cwhyu2 said:

There electronic locaters.but you have to call a plumbing contracter that
has this equipment.And it is not cheep

Click to expand...

OK, found a plumber that has the equipment and it's $400 just to walk in the door :-( They weren't very helpful on the phone. I wonder if the unit can be rented?

My sister used to do leak detection for the municipal water company. She said she could find a leak within about 6" or so. No idea what the equipment looks like. My guess is that it takes some practice, and even if you could rent it, your results may be lacking.

Instead of breaking up the slab, if you have one leak, there will be others soon, if not already there. It may be time to abandon all of those lines and run some new ones from the meter.

Take Jim's advice. Abandon the galvanized pipe, it's reached it's life expectancy and is shot. I would never encase water pipe of any kind in concrete. Sooner or later it will leak. My guess is it will cost less to repipe than to break concrete to patch the leak, and I promise you, if you patch this one, you will be doing this over and over again.

leak

call a professional leak detector, not a plumber. In this area locators have a flat fee for residential pipe and leak locating, and it is about $150.00, although a couple have increased it a bit. Who in their right mind would have installed galvanized piping undergroundl? Your cold water may come from the outside through a new connection.