How to Repair a Sink Water Supply Line Leak

What You'll Need
New water supply line hose
Plumber's Teflon tape
Adjustable crescent wrench

If a water supply line to your sink is leaking, you can easily replace the line and repair the leak yourself. This will save you a lot of money in calling a plumber to your home to do the work. This easy-to-use how-to guide will show you everything you need to do to repair a leaky water supply line to your sink.

Step 1 - Locate the Leaky Water Supply Line

Most sinks have a hot and cold water supply line; therefore, you will need to determine which water supply line is leaking. To do this, turn on one faucet at a time until you can find out which supply line is leaking water. Also, place an empty bucket underneath the sink to catch any water that may spill out while working on the plumbing of your sink.

Step 2 - Remove the Faulty Water Supply Line

To remove the faulty supply line hose, use a crescent wrench and turn the compression nuts on the line counterclockwise. Continue doing this until the seal on the compression nut is completely broken and you can remove the nut by hand. Do this at the water supply valve and at the base of the water faucet. Once both compression nuts been removed, you can simply discard the faulty water supply line hose.

Step 3 - Remove Old Plumber's Teflon Tape or Dope From the Stem Connectors

In most cases, you will see that the connection fittings for the water supply valve and your faucet have plumber's tape or pipe dope on the threaded ends. Therefore, you'll need to remove this. Simply unwrap the plumbers tape or used a sharp-edged object to carefully scrape away any plumber's pipe dope on the threaded connection fittings.

Step 4 - Install New Teflon Tape on the Stem Connection Fittings

Take the plumber's Teflon tape and wrap the threaded connection fittings on the water supply valve and underneath the faucet. Make three or four turns with the tape and make sure the tape covers all the threads on the fittings.

Step 5 - Install the New Water Supply Line Hose

Once the Teflon tape has been wrapped on the threaded ends of the connection fittings, you can now install the new water supply line hose. Simply tighten the compression nuts on the water supply valve and at the base of the faucet. Hand tighten the compression nuts and then use the adjustable crescent wrench to tighten them an additional one-half turn. When tightening the compression nuts, make sure not to use too much force or you could damage the connection fittings or the compression nuts themselves.

Step 6 - Test the New Water Supply Line Installation

After you finish installing the new water supply line, turn the water back on at the water supply valve and check the line for leaks. Once you're satisfied there are no more lakes, remove the empty bucket and use an old towel or rag to dry up any water on the lines or other fixtures.