How to Fix a Leak in a Newly Installed Sink Strainer Basket

What You'll Need
Sink strainer
Plumbers putty
Plastic putty knife
Pipe wrench or channel lock pliers

Sink strainers, also called sink strainer baskets or sink basket drains, are long lasting plumbing components. However, it is possible for a strainer to malfunction over time. If a strainer malfunctions soon after it has been installed, the problem is usually with the installation itself. 

Step 1—Determine the Leak is Actually from the Strainer

Just because there is water leaking from below your sink doesn’t mean that your sink strainer is leaking. Your trap could be causing the leak. The way to determine the location of the leak is to fill the sink with water and stop it up. Periodically check below the sink. If there is water around the rubber gasket or dripping down from the locknut, your sink strainer is the culprit. 

Step 2—Check the Locknuts and Gaskets

Before you remove anything, check to make sure that the locknut is tight. If it is loose, you may simply have to tighten it for the leak to disappear. If tightening the locknut doesn’t solve the problem, you will need to check the rubber gasket. The rubber gasket is supposed to make a water tight seal. However, over time the rubber can become stiff and develop tears. This can cause it to malfunction. If the gasket is damaged, replacing it with a new one may just do the trick. If not, you will have to remove the entire strainer. 

Step 3—Remove the Strainer

Remove the locknut with the channel locks or pipe wrench. Remove the gaskets and put the strainer through the opening in the sink. The other reason you may be getting a leak is because the plumber’s putty is giving way. On a newly installed sink this generally doesn’t happen unless not enough putty was applied to begin with. 

Remove all of the remaining putty from the opening to the sink and off of the flange. You will need to make sure that both are clean and dry before attempting to seal with more plumber’s putty.

Step 4—Add Plumber’s Putty

Once the sink and the strainer are clean and dry, you can add a ring of plumber’s putty to the flange of the strainer. Using about a golf ball size amount of putty, work it into a long snake-like shape. Wrap the length of the putty on the underside of the flange on the strainer. Fit the strainer, and the putty, into the opening in the sink and apply even pressure to secure it in place. Wipe up any putty that squeezes out from around the strainer. 

Step 5—Fit the Strainer Back Together

Now that the main part of the strainer is back in place, you can fit all of the parts back together. Remember you will need to attach the drain pipe to the threaded portion of the strainer. 

You can now do the same check you did earlier to determine if the strainer is leaking. You should have no problems now.

That’s it. You have now fixed a leak in a sink strainer basket and your sink is working as good as new.