How Do I Find a Leak in My Kitchen Sink?

Begin by clearing everything from under your sink. Use a flashlight to check all visible pipes, connections, and the drain assembly. Look for drips, water beads, or mineral stains, which indicate a slow leak. Also check the cabinet floor and walls for any signs of moisture, warping, or discoloration. This initial survey can often pinpoint the general area of the problem quickly.

A slow leak may not show active dripping. Feel the pipes and fittings with a dry paper towel to detect dampness. Pay close attention to slip nuts on the drain pipes and water supply line valves. If you see mold or smell a musty odor, the leak has been present for some time. Identifying these signs helps you understand the extent of the issue.

Drain leaks are frequent under kitchen sinks. Pour a small amount of water directly down the drain and watch the pipe connections below. Look for water escaping from the slip joint nuts or the drain basket seal. A loose connection or failed plumber's putty can cause this. Tighten the nuts by hand first; over-tightening with a tool can crack plastic pipes.

If you have a garbage disposal, check its mounting flange and dishwasher inlet connection. Run the disposal and look for leaks from its body or seams. A leak from the disposal housing often means the unit needs replacement. Also, check the dishwasher drain hose attached to the disposal. A faulty hose clamp or split hose can spray water under the sink during a cycle.

Some leaks are simple fixes, like tightening a slip nut. Others, like a cracked pipe or a leak inside a wall, require a plumber. If you cannot find the source after checking all visible areas, the leak may be behind the cabinet or wall. Persistent moisture or a recurring leak also signals a deeper issue that needs expert diagnosis to prevent ongoing damage.

Water damage from a leak may need restoration. If materials are warped, soft, or moldy, water damage pros can assess and dry the area. They address not just the water but also potential microbial growth. Policies vary, and your insurer decides what is covered. Document the leak and any damage with photos before starting cleanup, as this may be helpful for an insurance claim.

• Call a plumber for leaks from pipe walls, valve bodies, or inside faucets.
• Contact local water damage pros for wet drywall, subfloors, or cabinets.
• Seek help if you smell mold or see fuzzy, discolored growth.
• Get professional assessment if the leak source is not found after basic checks.
• Consider a mold professional if there is visible mold growth after a leak.
• Always shut off the main water supply if under-sink valves fail or leak worsens.