Leaking Kitchen Sink Drain

The kitchen sink drain is one of the most used parts of any home and one that is often the cause of water damage that eventually leads to mold problems due to water leaks. Troubleshooting a leaking kitchen sink drain is always a process of elimination. There are several types of issues that may be causing the drain to leak.

Inspecting a Leaking Kitchen Sink Drain

leaking kitchen sink drain

In every kitchen drain there is a section of u-shaped pipe under the sink called the drain trap. Before you do anything else, position a small bucket underneath the drain trap so that any water that escapes the drain as you work on it is caught in the bucket and doesn’t saturate the sink cabinet floor. Then grab a flashlight or trouble light so that you will be able to see better as you inspect the drain from below.

Next, use a towel or rag to dry all of the pipes under the sink connected to the bottom of the sink. This way, if you see any new water drips or leaks you will be able to see where they may be coming from.

Place a sink stopper in the kitchen sink then fill the sink with a couple of inches of water. Using adequate lighting, from underneath you should be able to determine where the drain is leaking.

Parts Making Up the Kitchen Drain

A kitchen sink drain is a fairly simple mechanism without too many complicated parts. The main parts are as follows:

  • Strainer body or basket
  • A rubber gasket
  • Locknut (there may be one at each pipe connection)
  • Strainer coupling
  • Drainpipe
  • P-Trap

Depending on whether or not you have more than one sink drain, dishwasher connections, and a disposal connection, there may be more pipes required. The above list is for a sink with only one drain.

What May Be Leaking and the Repair Required

If you discover a leaking kitchen sink drain, the following repairs should be done:

kitchen sink basket strainer

The strainer body/basket – if the leak seems to be coming from around the strainer body, it will probably be leaking because the plumber’s putty is no longer creating a complete seal around the hole in the sink. You need to unscrew the locknut on the underside of the strainer body. Be careful when you remove the locknut because there will be a 2-piece gasket above the locknut. Gently pry the strainer out of the sink. Clean away any old putty that is under the lip of the strainer. Take enough new putty to roll it into the form of a rope. Make the rope about one half of an inch in diameter and long enough to completely encircle the lip on the bottom of the strainer body. Once the putty is in place, center the strainer body into the hole in the sink and gently push down on the strainer body to seat it in the sink’s hole. You should see putty being squeezed out around the strainer body. Have someone hold the strainer body to keep it from spinning as you tighten the locknut on the underside. (don’t forget to replace the gaskets before screwing the locknut on). Once the strainer body is tightened, remove the excess putty from the top and bottom. Reattach the drainpipe and tighten the locknut that holds the strainer body and the drainpipe together. Re-plug the drain and refill the sink with water to check that the strainer body no longer leaks.

The connection between the strainer body and the drainpipe – a locknut connects these two parts together. If the locknut isn’t tight enough a leak will occur around the locknut. Simply tighten the lock finger-tight, and then add at least one half turn more with a pair of channel locks.

The connection between the drainpipe and the p-trap – this leak is fixed by the same method as connection between the strainer body and the drainpipe. The locknut should be tightened finger-tight then at least one half turn more with channel lock pliers.

Try to allow 2 to 3 days for the putty to set up before filling the sink with water and using it.

Look Closely for the Presence of Mold

Small leaks and drips under your kitchen sink as a result of a defective sink drain could have allowed mold to grow. This is especially true if the leak has been going on for a lengthy, undetermined time. Check the floor of the sink cabinet as well as both of the sink cabinet’s sidewalls and its back wall. It would also be smart to check inside of either cabinet that is next to the sink cabinet. Water will be absorbed from cabinet to cabinet. Mold grows well in damp, dark spaces and many of today’s cabinets are made of engineered wood, more like paper than solid wood. This engineered wood is composed of wood shavings, sawdust, or wood fibers that have been bonded together. These engineered wood cabinets are much more susceptible to water damage and mold growth.

Contact a Local Expert

Fixing a leaking kitchen sink drain is a fairly easy task for the average homeowner. However, if you open your sink cabinet and find mold growing, the scope of the job has changed dramatically. Instead of a DIY repair, it may be a good idea to seek professional help to remove the mold. Remember, mold brings with it a lot of possible health risks. You should never take on the task of removing mold if you or a family member has sensitivities to it or suffers from asthma or allergies.

If you experience water damage or if you discover mold as a result of a kitchen sink drain leak, you can get immediate, 24-hour information and assistance by calling 877-960-0491. You will be connected to a local IICRC certified professional water and mold damage expert that can answer questions over the phone, or come to your home to view any damage and inspect for mold. Their initial inspection and estimate for removal and repair are free of charge, and without obligation.

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DIY - How to Fix a Leaky Kitchen Sink Drain Pipe