My Water Heater Is On The Second Floor Of Our House (we Are On A Slab). After Using The Downstairs Bath Shower Or The Washing Machine (also Downstairs) We Hear A Dripping Sound In An Inside Wall. After A While It Stops.

I Have To Believe It Is A Leaky Line (we Have Those Gray Flexible Lines) From The Hot Water Heater Supplying Water To The Shower And Washer.

I Do Not See Signs Of Leakage Anywhere. I Do Have Some Access Through The Garage Wall To The Header Where These Lines Are Routed. Again, No Sign Of Leakage There.

Can Anyone Help? I Have Not Yet Called A Plumber.

This might not be a leak in your walls. Read on. Knocking, popping, creaking and crackling pipes are a common complaint, especially in colder weather. I can tell you what's happening and take the mystery out of it but you're not going to like the repair. When a draw is made on a hot water line the line expands against a pipe strap next to a stud and when you drain hot water from your tub or shower it goes into a chase that is a little cooler then room temperature. The heat expands the pipe causing it to rub against the stud to which it is pipe strapped. This is the sound you hear. As it cools it contracts and the noise is heard again. To repair it you must tear open the walls and locate the pipe strap that's causing the problem and shim it tight. Most people when they learn what causes it just elect to live with it. Regards, Tom

The pipes are in the walls coming down from the second floor. The pipes are usually stapped to the studs in the walls but they frequently allow the pipes to move a bit. The sounds goes away once the pipes have expanded. Tom did give some good thought to his answer and he is correct with his solution. I hear this complaint from many home owners and it has never been a leaking pipe yet, all were hot water pipes expanding. Trust Tom, I do.

The coefficient of expansion for plastic is greater than metal or copper. If you really want to test this out shut off your water heater for a day. Run hot, now cool, water and I'll bet my bottom teeth you won't hear the dripping sound. I usually recommend to customers that they ignoree the noise since the fix is pretty drastic. Good luck.