How to Repair a leaking Kitchen Sink


If your kitchen sink is leaking from where the sink basin connects to the drain and you are looking for help on how to fix it, you’ve come to the right place. In this instructional blog post I am going to show you step-by-step how to repair the leak. It may be the case that you need to replace the drain in order to repair the leak. Depending on when you catch the leak, you may be able to get by without having to replace drain. Either way, this post can be a help to you as you install a new drain, or assess whether to reuse the drain you have.

Before you get started disassembling your kitchen sink drain you may want to make sure you have the right tools and supplies for the job. You will need a flathead screwdriver, a hammer and, depending on how tight your drain pipes are, you my need a wrench. As far as supplies go, you will need plumbers putty, Vaseline and possibly a new kitchen sink drain. You can find all of these supplies and the tools at most hardware stores. If the seals on the sink drain are damaged, you will need to purchase a new drain, as the seals are sold with the drain. There are generally two seals that come with the drain. The first one is a rubber seal that goes up against the underside of the sink basin, and the second is a cardboard seal that goes over the rubber seal which protects the rubber seal from being damaged by the flange that holds the drain in place. If either of these seals are damaged, either by removing the drain, or, in the case of the cardboard seal, from water, you will have to replace the drain as the seals are sold with the drain.

Once you have your tools and supplies, you will want to unscrew the P-trap underneath the sink, or the section of pipe that goes from the underneath part of the sink to the P-trap, this can be done by hand, however, if the connections are too tight you may need to carefully use a wrench to loosen it first. Once the P-trap has been removed, you will want to take a flathead screwdriver and place the head of it on one of the tabs that are on the flange that screws down the drain. Carefully tap the screwdriver with a hammer pushing the flange in a counterclockwise movement to loosen the flange. This flange will most likely be on tight, and it will be very difficult if not impossible to remove by hand. Once you have loosened the flange you can unscrew it by hand.

How to loosen/tighten flange on kitchen sink drain

How to loosen/tighten flange on kitchen sink drain

With the P-trap removed, and the flange unscrewed, you can now carefully remove the cardboard seal and the rubber seal from the underside of the sink basin. Again, if either of these seals are damaged you will need to purchase a new drain. Remove the drain from the sink basin. Throughly clean the sink from any old plumbers putty. Make sure that both the underside, and the topside of the sink are clean and dry. If your seals are still in good condition you will also need to clean the drain and seals from any old plumbers putty and scum. You can rub a small amount of Vaseline on the rubber seal to help restore the seal.

Once the sink (and old drain if you are able to reuse it) is cleaned and dry roll some plumbers putty into a rope and wrap it around the drain where the drain will make contact with the topside of the sink. Next, place the drain into its proper position in the sink. On the underside of the sink, install the rubber seal first, and then install the cardboard seal. Now screw the flange that holds the drain in place onto the drain and hand tighten it. This flange should now be making contact with cardboardbord seal. To tighten the flange up, place the head of a flathead screwdriver on one of the tabs on the flange and carefully tap the screwdriver with the hammer causing the flange to tighten clockwise. Make sure to get the flange on nice and tight, however, do not over tighten it to where it damages the seals. Once the drain is installed you can reinstall the p-trap, or drain piping.

Kitchen sink drain with plumbers putty

Kitchen sink drain with plumbers putty

With the drain installed, and the drain pipes reinstalled, you will need to remove any excess plumbers putty that oozed out when tightening it down. You can do this with your hand, or by scraping around the edge of the drain with a flathead screwdriver.

Cleaning off excess plumbers putty from  kitchen sink drain

Cleaning off excess plumbers putty from kitchen sink drain

Now that everything is installed, you will want to check your work. Run water down the drain and watch for any leaks on the underside of the sink. Plug the drain and fill the sink with water, see if the seals are working the way they should. Check underneath, if you have see any leaks while the sink is holding water, the drain flange is either not tight enough, or you did a poor job sealing the drain with the plumbers putty and seal installation. If this is the case you will need to redo your work. If you see no leaks, congratulations, you have successfully repaired your sink drain!

If you live in the North Houston area or surrounding cities such as The Woodlands Texas, Spring Texas, Humble Texas, Atascocita Texas or Kingwood Texas, give me a call if you need help to install your kitchen sink drain. Simply contact me via the email address below, or at the “contact us” page. Thank you for taking the time to visit this blog, I hope it has been helpful.