If you accidentally hit a waterline pipe while drilling a hole in the wall, say, to hang a medicine cabinet or shelf in the bathroom, you need to fix it as soon as you can. After you open the wall and find out what size waterline pipe your house has, you'll need to buy a push-fit coupling, or fitting, to repair the damage. Sounds complicated and maybe a little scary, right? But it's not, really. With a push-fit coupling, there is no soldering, no clamps, no glue and no wait time. With a push-fit coupling, you will confidently tackle this repair project.
Shut the water off, either at a valve above the leak or the main line. Water will continue to run until the line is drained. Open the faucet at the sink to allow water to drain out of the faucet rather than through your wall.
Remove the drywall around the damaged line with a drill or a drywall saw. If you use a drill, drill holes close together and punch out small sections of the wall until you have enough room to access the damaged line. Be careful not to hit the waterline again.
Determine the size of the pipe. Typically on PEX and PVC pipes, the size is printed on the outside of the pipe. If it's not printed, or your waterlines are copper, wrap a string around the outside of the pipe to measure the circumference. The "official" size is really the inside diameter, so bring the string measurement with you to your local hardware or home improvement store. The salesperson will help you choose the proper coupling size from the length of the string.
Purchase a straight push-fit coupling in the proper size. There are two types, a permanent one and a removable one. If you think there will be any chance that you'll need to take the coupling off in the future, choose the removable one. It comes with a small C-shaped device that allows you to take it off.
Line up the PVC cutter just above the hole in the pipe, as level as possible, and cut the pipe as close to the hole as possible. Then cut the pipe just below the hole, removing the entire section of damaged pipe. Don't cut any more than you have to.
Install the coupling according to the instructions on the package. Each end of the coupling has plastic inserts that fit into the ends of the pipe. Mark the line according to the instructions. Slide the first end of the coupling onto the pipe. Push the pipe firmly, with a slight twisting motion, until it reaches the tube stop. Then slide the other section of pipe into the other end of the coupling and push/twist until it hits the stop. You may have to slightly bend the pipe to get it into the coupling. Be sure both ends are secure.
Wipe the pipe and coupling dry. Turn the water back on. Once the water pressure returns, you will know quickly if your repair job was a success. If you connected the coupling properly, the water will flow and everything in the wall will be dry.