What Are the Signs of Water Damage Under Kitchen Sink Cabinets?

The most obvious sign is discoloration on the cabinet floor or side panels. This often appears as dark water stains or yellowing, especially on particle board or plywood. These stains indicate that water has pooled and been absorbed. The wood may also feel damp to the touch, confirming an ongoing or recent leak from the plumbing above.

A persistent musty smell is a strong clue of hidden moisture. Mold and mildew thrive in dark, damp spaces like under-sink cabinets. You may see fuzzy black, green, or white growth on pipes, walls, or stored items. Mold can develop quickly after a leak, especially in environments with fluctuating humidity.

• A persistent earthy or sour smell from the cabinet.
• Visible mold colonies, often black, green, or white.
• A damp, stale feeling in the air when you open the door.
• Mold growth on stored cardboard boxes or paper products.
• Discoloration on pipes, especially around joints and connections, which may feel damp.
• Condensation on the cold water supply lines that promotes growth.

If you discover water damage, your first step is to stop the water source by turning off the supply valves under the sink. Remove all items from the cabinet to allow air circulation and assess the full extent. Document the damage with clear photos for your records, as this is helpful for any discussions with your insurance company or with repair professionals. Then, contact local water damage pros for a professional assessment. They can determine the needed cleanup and repairs, which often involves specialized drying equipment to prevent mold.

• Immediately shut off the water supply to the sink.
• Clear out all contents so you can see the full area.
• Wipe up any standing water with clean towels.
• Take detailed photographs of all visible damage.
• Increase ventilation by opening cabinet doors and windows.
• Contact qualified professionals for a thorough inspection.