Kitchen Sink Leak Repair

Two men working beneath a kitchen sink
  • .5-3
  • Intermediate
  • 20-150
What You'll Need
Replacement washers, seals or pipes
Drain snake
Rubber gloves

Even a small kitchen sink leak can result in a significant amount of damage if it is left unchecked. By following a few steps, you can undertake the repair of a leak and prevent damage to your home.

Step 1 - Inspect

The first indication you get of a leak will often only be a pool of water or water damaged cabinets or flooring, so it is important to investigate to determine where the leak is coming from. Start by placing a dry empty bucket beneath the sink where you believe the kitchen sink leak originates. Plug the drain with the stopper and turn on the faucet until the basin is filled with about an inch of water. Leave the water in place and check beneath the sink to see whether any is escaping. Following this, pull the plug and let the water drain away while continuing to observe the pipes beneath the sink. A slow leak may not automatically present itself so use a clean dry rag or kitchen paper towel to gradually daub each section of the pipe and underneath the sink to find the location of the leak. If you have a kitchen sink sprayer, check beneath the sink while it is in operation.

Step 2 - Tighten

man tightening a plumbing pipe

A kitchen sink leak can often be caused by something as basic as a loose nut or fastener. If the leak has arisen for this reason, tighten the relevant section using the correct tool. The main waste pipe that leads from the kitchen sink is usually an “S” or “U” shaped component which comprises of joints that can be tightened by hand; improve your grip by wearing rubber gloves during this process. Use a wrench to tighten the slip nuts on the water supply pipes if necessary. Carry out another daubing test to make sure that the leak is no longer present.

Step 3 - Replace

Where the kitchen sink leak comes from below the sink trap but there does not appear to be any apparent reason, the problem may lie with the washer or seal inside. If a seal has become dislodged or worn, it will no longer be able to do the job it is made for and will allow water to pass through. Worn washers that are used as part of faucets will also allow water to pass through and will need to be replaced. Undo the fasteners and remove the washers and seals before replacing them; if necessary, take them with you to the hardware store to ensure that you get the correct sized replacement.

Step 4 - Repair

If your kitchen sink leak is present due to a pipe which has split or sustained some other damage, it may be easier to replace it rather than repair it. Unscrew the fasteners at both ends of the damaged section and take it with you to the hardware store to obtain a replacement. A leak can occur because water backs up due to a clog so ensure the drain remains clean to stop this happening.