Can a Slow Drip Under the Sink for Months Cause Floor Rot?

A slow drip under the sink might seem minor, but over months it saturates the cabinet floor and the subfloor beneath. Water seeps through tiny gaps in the caulk or seams, and the wood stays wet for long periods. That constant moisture breaks down the wood fibers, leading to rot, warping, and a spongy feel underfoot.

The damage often goes unnoticed because the leak is hidden inside the cabinet. You might only spot a dark stain on the cabinet base or a musty smell. By then, the rot can extend beyond the sink area, affecting the joists or the flooring in the adjacent room. The longer the leak continues, the more extensive the repair becomes.

Wood rot is not just about the visible surface. The moisture travels along the grain and into the subfloor, which can be a thick layer of plywood or oriented strand board. Once rot takes hold, it can weaken the structural integrity of your floor, causing it to sag or feel unstable.

In a humid subtropical region, the air already holds a lot of moisture. That means the wood under your sink never fully dries out, even after the leak stops. The rot can continue to progress, and mold can grow on the damp wood, which is a health concern for your family.

Local water damage pros have the tools to assess hidden damage, such as moisture meters and borescopes. They can determine if the rot has reached the floor joists or if mold is present. If the subfloor needs replacement, they can remove the damaged flooring and install new material properly.

Repairing floor rot often involves removing the sink, pulling up the flooring, and replacing the subfloor. This is not a simple DIY job for most homeowners. The pros can also check for other leaks in the area and help prevent future damage. The cost depends on the extent of the rot and the type of flooring you have.