How to Replace a Toilet Water Supply Line

What You'll Need
New toilet water supply line
Plumber's Teflon tape
Adjustable crescent wrench
Empty bucket
Old towels or rags

If your toilet water supply line is causing leaks, you can easily replace the old supply line with a new one. Replacing a water supply line for your toilet is much easier than you might imagine and can be done in just a few minutes. In fact, this handy how-to guide will show you everything you need to do to replace the water supply line to the toilet in 30 minutes or less.

Step 1 - Turn Off the Water Supply to the Toilet 

Locate the shutoff valve for the water supply line. Usually, it is located directly beneath the tank of your toilet and close to the floor. Turn the valve clockwise to tighten it. Continue turning the valve until the water supply to your toilet stops flowing.

Step 2 - Drain the Toilet Tank

Before you replace the water supply line hose, you'll need to drain the toilet tank. To do this, simply flush the toilet with the handle. If you cannot use the handle to flush the toilet, you'll need to reach inside the toilet and lift the flapper at the base of the tank. Also, place the empty bucket underneath the toilet tank to catch any water that may spill out while replacing the water supply line.

Step 3 - Remove the Old Toilet Water Supply Line

Take the adjustable crescent wrench and loosen the nuts at the base of the toilet and at the water supply valve. Once the nuts have been loosened with the wrench, continue turning them counterclockwise until you can remove the water supply line. Discard the old water supply line hose. Also, remove any old plumber's Teflon tape from the connection stems on the water supply valve and at the base of the toilet.

Step 4 - Install the New Toilet Water Supply Line

Use the plumber's Teflon tape and wrap the stems located at the water supply valve at the base of your toilet. Teflon tape is used to make an airtight seal between the compression nuts on the ends of the water supply line and the connectors. Wrap the stem connectors three or four times with the tape and then twist on the compression nuts at both ends of the water supply line. Tighten the nuts with the adjustable crescent wrench until they're about half a turn passed hand-tight.

Step 5 -Turn the Water Back On

Turn the water supply counterclockwise to restart the flow of water into your toilet.

Step 6 - Check for Leaks

As the water begins to flow back into your toilet tank, carefully check the areas where the compression nuts fit onto the stems of the water supply valve and at the base of your toilet. Dry them thoroughly with an old towel and then check again with your fingers to make sure the connections are still dry. If you feel water present, there's a chance that a leak still exists and you may have to start over. If the connections are dry, your leaky water supply line problem should be fixed.