How can you find a leak in the plumbing system?

Question

The bathroom upstairs is of a concern and I don't know how to check if the commode, the sink, or the shower pipes have a slow leak.

The reason is bc there's a patch (fresh paint) on the wall as if part of the roof from downstairs (right below the bathroom upstairs) was repaired recently.

We know we can get an inspector but I'd like to do a basic test on it before.

Answer 1

Basically, if you want a simple test for water leaks, just go to your water meter, and observe the dial flow indicator. It is the small arrow that spins as water flows through the meter. If everything in the house is off, the dial indicator will not move. If it is moving, water is flowing somewhere. Finding leaks is more of a problem, because most piping is concealed, making a leaking pipe hard to locate. Water will travel horizontally across long areas sometimes, before it appears, making it difficult to determine exactly where the leak originated. If you have determined the leak is not from the water lines, turn on one fixture at a time, and run water for at least 10 minutes, before turning on the next fixture. Most likely there was a leak, and it was repaired, thus the "new" paint, to mask the stain. A common leak occurs in upstairs baths, when an old vinyl floor is removed, and a new ceramic tile floor is installed. This is a common upgrade, that lots of people have installed, prior to a sale, to make the home seem more modern. The problem arises when unqualified people try to perform plumbing work. Tile setters will remove and replace the toilet, but they don't know what all is happening, when they raise the floor, and try and reset the toilet. The toilet flange is still fastened to the original floor, and now it is lower than the new floor. This requires a flange extension to be installed. If they only used a thicker wax ring, it will usually start to leak within a few weeks of the reinstall date. I hope this helps.

Answer 2

More than likely its a slow leak from the drainage coming from any of these items. What you could do is push on this patch on the ceiling and see if you can poke your finger or something else through it easily. If the drywall is wet it will be easy to do this. Let the water drain into something. Get rid of all that excess water and let air circulate. Go ahead and run the water from one of the 3 like the toilet a few flushes and observe if water runs only when this happens. Repeat for all. If its a constant leak from that small hole then its the copper fittings leaking but highly unlikely. Also check the tub spout to see if it has enough caulking around it to stop any water from flowing into it. Start simple first and work your down. Some people have gone as far as using food coloring in the sink mixed w the water to tell if its coming from that pipe.