We've had a few troubles with the pipes in the slab recently. A few months ago, Anderson came out to repair a radiant heat leak with great success... Most recently, a cold-water potable leak was causing super-high water bills...
We found the source of the leak with the help of American Leak Detection. Afterward, we called All-Pipe Restoration (Ace DuraFlow) to fix the leak using their epoxy-coating system.
This process saves jack-hammering up the floor -- which in our case would have been tough as the lines were quite thick in that area -- heat, water, etc... all converging in one spot. The process also protects the entire branch, not just the one spot that was leaking, so it might be good down the road.
Essentially, they break open the lines, blast them clean, flood them with epoxy and let that harden inside the pipe, forming a PVC-like lining inside the pipe. After treatment, you can't solder the pipe anymore and if you do the whole house, you have to take off the supply valves, but in our case, we just fixed one main supply line from one manifold to the next -- a pretty easy run. The flow is also as good (or better -- since the line is now clean and smooth).
So far, so good... so, if you've a problem, give Sergey a call (pictured below with... Sergey (#2)).