There are several reasons why a toilet water supply line would leak. It could be a hole in the line or worn out treads in the connection. Troubleshooting this problem is the first step to fixing it. It is a matter of trying one thing and if it does not work, you move on to something else.
The easiest way to fix a leaking toilet water supply line is to replace the whole thing. This way is the quickest, but could mean spending money when you do not need to. Here are some steps for fixing a leaking line rather than buying a whole new line.
Step 1 - Find the Leak
First, you will need to determine where the leak is coming from. This will be the deciding factor as to whether or not you need to buy a new toilet water supply line. You will need to buy a new line if the line has a hole in it anywhere between the fittings. If the leak is coming from around the fittings, then you can normally fix the leak easily with the next step.
Step 2 - Tighten the Fitting
If the leak on your toilet water supply line is coming from around the fitting, it can usually be fixed by just tightening the fittings a little tighter. You need to take your small pipe wrench place it on the fitting and very gently tighten the line. If the leak stops, you are done. If not, move on the the next step.
Step 3 - Checking the Washers
If tightening the toilet water supply line did not work, you may have bad washers. You need shut the water off at the shut off valve. Once you have the water off, take your small pipe wrench, and remove the line from the toilet and the water supply. There will a rubber washer in each fitting. Remove the washers and replace them. Reattach the line. Turn the water back on and check for leaks. If you still have a leak move on to the next step.
Step 4 - Putting on Plumber's Tape
If replacing the washer did not work, you may need to put plumbers tape on the fittings connecting to your toilet and the water supply. Remove the line just like you did in step three. Wrap the tape around the treads of the fitting on the toilet and the threads that attach to the water supply. The leak may be from worn treads on the fittings. The tape will help fill in the gap. Replace the toilet water supply line and check for leaks. You may choose to do this at the same time you replace the washers.
If you have gone through these steps and still have a leak, you will need to buy a new line.
Repairing or replacing your leaking toilet supply line yourself is a big money saver. Enjoy the satisfaction of a job well done1