Common leak points and what they damage
| Leak point | Typical sign | What gets wet |
|---|---|---|
| Slip-nut joints on the sink drain | Water stains or swelling on the cabinet floor | Cabinet base, back panel |
| Supply line or shutoff valve | Corrosion on the valve, damp items stored below | Cabinet base, wall behind |
| Garbage disposal seals | Drips from the bottom of the unit | Cabinet base |
| Dishwasher supply or drain hose | Warped flooring in front of the dishwasher | Subfloor, toe kick, adjacent cabinets |
| Refrigerator ice maker line | Stains on flooring or the ceiling below | Subfloor, basement ceiling |
| Failed caulk at the sink rim | Swollen countertop edge | Countertop substrate, cabinet top |
Why kitchen leaks hide so well
Most kitchen cabinets in production homes are built from particleboard or medium-density fiberboard with a thin laminate or veneer face. These materials soak up water readily, swell, and lose strength. Once wet, the cabinet base can hold moisture for a long time, especially with cleaning supplies and bins stacked on top of it.
Dishwasher leaks are even harder to see. The appliance sits on the subfloor behind a toe kick, and a small drip from a fitting may run under the adjacent cabinets. The first clue is often a floor that buckles, or a stain on the basement ceiling directly below the kitchen.
Because the leak is slow and clean water, many owners assume it is harmless. Weeks of steady wetting on wood products are exactly what mold needs.
Checking a suspect cabinet
Empty the cabinet
Remove everything and look at the base and back panel with a flashlight. Swelling, softness and dark staining are the signs.
Run water and watch
Fill the sink, then release it while watching the drain joints. Run the dishwasher and look at the hose connections.
Check below
If the kitchen is over a finished basement, look at the ceiling directly underneath for stains.
Shut off and dry
Close the shutoff valve if a supply line is leaking and leave the doors open with a fan blowing into the cabinet.
Save or replace
| Often salvageable | Usually replaced |
|---|---|
| Solid wood face frames and doors with surface spotting | Swollen or crumbling particleboard bases |
| Cabinet boxes where the base is dry, firm and only lightly stained | Laminate flooring that has cupped or delaminated |
| Tile flooring once the subfloor below is confirmed dry | Subfloor sections that are soft or show growth on the underside |
| Toe kicks and panels with growth on the hidden side |
General information for Highlands Ranch, not a quote or professional advice. In an emergency, call 911.