I noticed a large puddle in the middle of my basement floor last night. I looked up and the ceiling tile had a wet ring around it.

My first thought was that someone upstairs overflowed the sink in the kitchen above. I pulled the tile and had a look. The sink was about 8 feet away from the leak. Hmmm. Then I touched and messed with the insulation (which was dry) and inspected the wood sub-floor. It was dry too.

Second thought. The sink drain runs right through there. It must be leaking. However, No visible indicators that the sink line is leaking either. Clean as a whistle.

Third, It couldn't be the copper lines under pressure because I've never heard of a leak starting and then stopping. They were not leaking when I looked at them. However, one copper pipe was very green with patina over a 24" section just above the leak circle. Also, the bottom of that section of pipe had a slightly wet sludge to it. Also, over the years, when I'm in the basement watching TV, occasionally, I hear a rapid pipe ticking coming from that area. I always assumed the pipes were adjusting to heating and cooling.

On a side note, I have been shutting of the water in the house frequently to diagnose a water leak in the main service line in the yard.

Question: Could shutting off the water, relieving pressure, then turning it back on cause a temporary leak in a corroding copper pipe? I am imagining a hole that closes when the pipe is under house pressure and opens when the pressure is turned off. Seems opposite of what would actually happen, but just asking the question.

Thanks!

A water leak can travel some distance before it drips down... the leak is not always near where the puddle is discovered. It would take careful examination with a strong flashlight to find its source sometimes. When you find it right away you are lucky.

Does the pipe you inspected run near or at the bathroom? Im asking because one source of an active / inactive leak can come from a shower line. It will only leak when the shower is running. Running the tub or other faucets will not cause it to leak.

Does the pipe you inspected run near or at the bathroom? Im asking because one source of an active / inactive leak can come from a shower line. It will only leak when the shower is running. Running the tub or other faucets will not cause it to leak.

No, I think it supplies the faucet in the back of the house. It's under more pressure when the hose is off, so I'm confused as to why it would only leak sometimes.


A water leak can travel some distance before it drips down... the leak is not always near where the puddle is discovered. It would take careful examination with a strong flashlight to find its source sometimes. When you find it right away you are lucky.

I agree about the traveling, but this happened above a suspended ceiling grid. I wouldn't expect it to travel beyond the grid border much. Also, the tile itself was almost dry when I found it and nothing above it was wet. I'm wondering if an unreported kitchen spill happened several days ago and was only found yesterday.

green with patina over a 24" section just above the leak circle.

I think you have or are about to have a pin hole leak in the pipe. Sand that section of pipe well and look for moisture. Be prepared, if you sand the pipe well enough, chances are that the leak will change from oozing or dripping to spraying.