The first thing I noticed was warm/hot water coming out of the cold side of my faucets. I checked this site and decided to have the cartridges replaced in my faucets, so 4 out of 5 faucets were done (3 are Moen). The 5th faucet is in a shower stall not being used as a shower, just storage. I have just found out that this 5th faucet (moen) is "frozen" so I should have had the catridge replaced in that as well. However, it is a long shot that this last faucet is causing the problems.
My 1 1/2 yr old gas water heater turns on very often, just about every time I run water. The floor in my kitchen is very warm over about 1/4 of the floor. I live in a 1 level townhome built on a slab, about 30 yrs old. I had the gas company out to check the water heater. The tech says heater okay, and he thinks a hot water pipe under floor is broken. The hot water leaking out warns the cold water pipes laying alongside. This is why I get a one shot of cold water , about 1 minute of warm/hot water and then back to cold water when I turn on any cold water faucet.
I am going to try to find out if my water usage is way up to help determine if there is indeed a leak. Obviously, I don't want to tear up the floor unless I'm pretty sure.
Any thoughts will be very appreciated. Thanks! Gale

It sounds pretty good that you have a broken pipe. The equipment to locate the break is not cheap nor is the repair. Call a few plumbing outfits and ask them if the have thermal cameras or sensitive sound equipment to locate a break under a slab.

You can play doctor to see if you have a leak, use a long screwdriver touch one end to the hot water pipe at the water heater, touch the other end to your ear, if you think you hear water running it is almost certain that you have a leak. Then you can watch your water meter with everything turned off in the house, if the meter still shows movement you can be almost positive you have a leak.

Better yet, should all faucets and fixture off including the ce make. Check your water metere to see if the little arrow point is stopped or spinning. Any movement means a leak. I think your is spinning as we speak.

Ballengerb1 said it: turn water off and see if meter moves.

Slab leaks are frequent and repairs are not cheap. If you indeed have a slab leak then your HOA should be responsible for the cost or repair. If not, then call Leak Detector Contractor who will locate the leak first. You have 50/50 chance that the hot water line could be relocated through ceiling w/o cutting up your floors. Good plumber can be able to isolate the leaking branch, cap it off, and reroute the pipe. Please, keep us posted about the outcome as we all learn as we go...

Gale again. Thanks to all of you for your common sense advice about how to determine if I have a leak. It's amazing what is so simple and sensible, but you don't think about it in times of stress (or maybe never)!
I called my City Water Dept today and their records show that my meter "registered" a leak on Oct. 13. Everyone in this City was required to upgrade to these brand new meters earlier this year, so I had one. Obviously, I did not know it had a leak sensor. A technician from the City is coming out Monday to try to exactly locate the leak. I am assuming he'll have that sophisticated eqiupment you have mentioned. If not, I'll heed your advice, as after this one City visit I'll be on my own to get this fixed.
I called my HOA and they are claiming no responsibility, as I "own" the land under my townhome. I am puzzled why they replace roofs under the contractual responsibility of external maintenance, but they have no responsibility here. I was so hoping!
Thanks again. I'll go back and (highly) rate your answers, when I come back next week w/ outcome. I am new to this site and I think I may be making mistakes using it!(?)
Gale

Hey Gale, I am on a HOA board now and have been on the outside of the fence too. Ask them to show you documentation in the deed and legal description that says you own the land under your unit. In most HOA Town homes you own from the interior paint skin inward, they own everything on the other side of the paint.

It's Gale, back w/ the outcome. I DID indeed have a broken hot water pipe under my kitchen floor. I had a company called American Leak Detection out last week. They had super sound equipment and x-d a spot on the floor after extensive tests. I had a plumbing company out this week who jack-hammered through the vinyl and asphalt, clipped through some screen mesh stuff and dug down two feet through black dirt to find the pipe. The copper pipe was kinked w/ a small slit in it. The plumber thinks the pipe was kinked when put in years ago, and just wore out over time. The actual location of the pipe was about a foot off from "the x", but the plumber says that was not bad of American Leak Detection considering how deep down it was. The pipe was not an easy fix due to depth and angle. The plumber was here 3 1/2 hours, so you know it was a big job. This time does not include another person who came later and poured 3 bags of asphalt and smoothed out the concrete (about another hour). I was fortunate to have had excellent people here who were amazingly reasonable :) Now I am on to the project of getting a new floor.
My insurance issues took an interesting twist. I found out that my own home owner's policy (nothing to do w/ the HOA) will cover most of the costs associated w/ this leak. They will not pay for repair of the pipe, but they will pay for digging the hole, refilling the hole, and the new floor I need. I've already had a claims guy out here. He is uncertain about my bill for $350 from American Leak Dectection, but I am hopeful. Like I told him, you can't fix a slab leak until you know where it is (common sense!).
So, for anyone w/ a similar situation, check your policy! THANKS to everyone who helped me out w/ issue.
Gale

You were lucky! Lots of Home owners insurance companies do not cover water leaks under the floor or the damage that is done to repair them.

If I were you I would give you insurance a big endorsment on here.