Your Practical Guide to Fixing Under-Sink Drain: Kitchen Drains, Sink Pipes and Shut Off Valves

March 16 2020 – Natalie Harvey

Leaking Pipes, Drains, Valves? We've got you covered!

Knowing how to fix a leaking sink drain is an important part of caring for your home. Not only can a leaking sink or pipe cause a ton of damage to your home quickly, but having a professional plumber come to fix it can cost you a small fortune. While sometimes enlisting the help of a professional is a must, there are other times when you can handle the project yourself. All you need is a little bit of knowledge and a few tools.

The first step to fixing your leaking sink drain is identifying what is leaking. The most common leaks come from sink pipes, sink drains, and shut off valves. To determine where your leak is coming from is pretty simple. Most of the time you can tell rather quickly just by taking a look under your sink.

Below is a practical guide to help you fix the three most common causes of under-sink leaks on your own.

  1. Leaking Sink Drains
  2. Leaking Sink Pipes
  3. Leaking Shut Off Valves

When working to fix a leaking sink drain, you most likely will need to replace the basket strainer. To get started, you’ll need to remove your sink’s drain so that you can replace the basket strainer yourself. For this project, you’ll need some tools:

  • 4-in-1 Screwdriver
  • Adjustable Wrench
  • Hammer
  • Locking Pliers and Slip Joint Pliers
  • Rotary Tool

You’ll also need some plumber’s putty, which can be found at any local hardware store.

You can find several step-by-step tutorials for fixing your leaking sink drain by replacing the sink strainer basket, but in general, you’ll need to use the slip-joint pliers to loosen the coupling nut at the base of the strainer basket. Then you’ll need your wrench to unscrew the strainer locknut.

Once removed, you’ll take the plumber’s putty and roll it into a rope so that you can wrap it around the opening of the sink drain. Once the putty is in place, you’ll put the sink strainer back in and retighten the locknut.

If you need a brand new sink basket strainer, you’ll want to look for one that’s high quality, which means it has a durable finish and either a spin-lock or twist-and-drop stopper. You will want to avoid almost all push-in strainers for your kitchen sink because they tend to break with use.

Fix Leaking Sink Pipe

The first step when it’s time to fix leaking sink pipes is knowing how your sink works, which means getting familiar with all of the different parts. Starting at the sink drain, you’ll find the tailpipe, which leads into the P-trap. (The p-trap looks more like a “J” than it does a “P”.) From the P-trap, you’ll find another pipe that attaches to the waste line in your home. If you can’t identify which pipe is leaking under your sink, you might want to replace them all so that you don’t have another leak (and another project to tackle immediately).

To get started, place a bucket underneath your pipes and turn off all water valves to the sink. Once you have your replacement pipes ready, you’ll want to start from the top-down, working first on the tailpipe nut under the sink basket before moving to the P-trap. It’s likely you’ll find debris in the P-trap, so have a bucket ready.

Once the P-trap has been removed, you’ll work on loosening the nut on the last pipe, which is the one that feeds into the waste line either in your wall or floor.

Now you can start adding your new parts, beginning with the gasket for the new tailpipe and then attaching that to the P-trap opening. During this part, you’ll want to double-check that you have the gasket placed between the nut and facing the threads on the P-trap. Finally, you’ll connect the last pipe the same way, manually tightening all nuts before using pliers.

Fix Leaking Shut Off Valves

If you have a leaking shut off valve in your kitchen (or bathroom), your best bet is to completely replace it rather than spending your time rebuilding or fixing the old one. When buying your new shut off valve, look for a quarter-turn ball valve, which is the modern update. Easy to install, a quarter-turn ball valve rarely locks or leaks, which means you can feel confident after your repair is complete.

Once you’ve fixed your leaking sink drain, it’s a good idea to invest in an under-sink cabinet mat, which will protect your home from future damage and give you peace of mind if and when any other sink leaks occur. Xtreme Mats are the best on the market, designed to fit your cabinet and offering the best comprehensive protection. From general wear and tear to hazardous leaks, your under-sink cabinet is covered with an Xtreme Mat.