Under sink leaks, whether in the kitchen or bathroom, are some of the most common types of leaks in the home. Being able to diagnose them promptly ensures they are repaired before extensive damage occurs.
Signs of an Under Sink Leak
Leaks beneath the sink are typically caused by the drain pipe. One of the first symptoms of a problem is opening up the cabinet door to discover that the items stored there are wet or damp. If the cabinet is empty, you may notice that the bottom of the cabinet appears damp or discolored. There may also be a musty odor from developing mold and mildew. The sink drain may also be emptying slowly since leaks are often indicative of a clog.
Sometimes it is the water supply pipe and not the drain that is leaking. When this is the case, you may have reduced water flow or pressure at the sink tap. Symptoms under the sink can be similar to a drain leak, but often the dampness and water damage is on the back wall of the cabinet as opposed to the bottom of the cabinet.
Drainpipe leaks can be caused by an aging or damaged pipe. This is particularly common for metal pipes. Leaks can also form at the pipe joints or where the garbage disposal gasket seals into the drain pipe. Clogs are another common cause. As residue builds up in the drain, it puts pressure on the pipes and can lead to leaks along any joints.
Water supply pipe leaks are usually caused by damage to the line. In many cases, the cause is hard mineral buildup in the line that leads to increased pressure and burst or cracked pipe. Sometimes the line is fine, but the connection to the sink faucet has failed. In this case, the leak will be right where the water supply pipe connects to the sink.
Drainpipe leaks will require a replacement pipe if there is damage. Otherwise, your plumber will clean out the pipe to remove any clogs. They may also need to clean out the garbage disposal and replace the gasket at the drain attachment point. Joints will then be tightened until they seal properly.
Water line leaks may require minor construction since these pipes typically run behind the cabinet wall. A portion of wallboard will be cut out and then the damaged pipe will be located and replaced. Afterward, the wall is patched. If the leak is at the sink attachment, then a new washer or gasket may be all that is required.
Contact a plumber for pipe repair if you notice a leak beneath your sink.