Make a Temporary Repair to a Leaking Sink Drain

Knowing how to temporarily stop a leak gives you time to gather information and materials for a more permanent fix. (Bacho/Shutterstock)

Dear James: I noticed a damp spot from an extremely slow leak under my kitchen sink. I cannot afford to call a plumber right now. Is there some method to temporarily repair it? —David J.

Dear David: A plumber would rightly recommend that the drain should be replaced, and it will eventually need replacement. Even though it’s a relatively minor job for an experienced plumber, it’s expensive to have the plumber just walk in the door and inspect it. Once the leak is stopped, you'll have time to study videos on how to replace the pipe yourself.

Place a pan under the drip to catch the water. Place it on something to raise it off the floor so it will dry out. Since you may not know how long the pipe has been leaking, there may have already been some damage done to the building materials or ceiling below the leak.

Check to see how damp things are and whether you notice any weak or rotted wood on the bottom of the cabinet under the sink. If there is much damage, you will probably have to call a contractor to repair the damage. Most home improvement and repair contractors can also easily replace the pipe at the same time.

Since it’s a very slow drip and the hole in the pipe is so tiny, it may be difficult to find. Keep in mind, water runs down a pipe, so where it appears to be dripping may not be the exact location of the hole. Wipe the entire pipe dry and quickly wrap a tissue around it. Watch for where the tissue first gets wet to locate the hole.

Your concern now is to stop the leak with a temporary fix long enough to get to your home center store for materials for a longer-lasting patch. With the pipe dried off, wrap waterproof tape around the leaky area, covering about six inches more on each side. Black electrical tape, duct tape, or aluminum tape should work well.

The two most common methods to replace a leaky metal pipe are using plumber’s epoxy or a pipe clamp. The plumber’s epoxy is also particularly effective for sealing leaky fittings. To use the epoxy, you must shut off the water to that pipe and be sure no water still drips from the hole.

The exterior of the pipe must be very clean for good adhesion. Clean it with detergent to remove any grease or oils. For added insurance, use medium-grit sandpaper and sand it down to the bare metal. This cleans the surface and creates a rough surface for better adhesion.

Read the instructions on the packaging to determine how much working time you will have before the epoxy starts to harden. Mix the two parts together and spread the mixture over the hole with a putty knife. Put it on thick. If it’s difficult to reach, use your fingers. Always wear protective gloves when working with epoxy.

If the leak is easy to reach, installing a pipe clamp over the leak is effective. Get the proper size for the pipe diameter. Place the rubber pad from the kit over the hole in the pipe. Close the hinged clamp over the rubber pad and tighten the screws.