Parts that commonly leak
- Supply line
- The flexible hose from the shutoff valve to the faucet or dishwasher. Older rubber lines crack and weep.
- Angle stop
- The shutoff valve under the sink. Old multi-turn valves can drip at the stem.
- P-trap and slip joints
- The curved drain pipe and its compression nuts, which loosen over time.
- Garbage disposal
- Can leak from its body seals or drain connection as it ages.
- Dishwasher door gasket and tub
- A worn gasket or cracked tub drips under the unit where it cannot be seen.
A five-minute check
Do this a few times a year with a flashlight.
- Cabinet floor is flat and firm, not swollen or soft
- No stains, rings or dark spots on the cabinet floor or back panel
- Valves, supply lines and trap joints are dry to the touch
- No musty smell when the cabinet first opens
- Flooring at the dishwasher's front edge is not lifting
- If there is a basement or crawlspace below, the ceiling or subfloor under the sink is dry
How these leaks spread
Sink base cabinets are usually built from particleboard or plywood that swells and holds water. Below them, many older Wheat Ridge kitchens have plank or plywood subfloor with several layers of flooring on top, sometimes including old sheet vinyl. A drip finds its way through seams and into the subfloor, then spreads sideways under the finished floor.
Dishwashers make it harder still. They sit in a dark opening, and a leak from the door, the tub or the drain connection runs underneath and behind, toward the wall and into the subfloor. By the time flooring lifts at the front, the area under the unit may have been wet for months.
Sequencing the repair
Stop the leak
Close the valves or the main and have the plumbing repaired or replaced.
Look underneath
From a basement or crawlspace, check the subfloor and joists under the sink and dishwasher before deciding what to remove upstairs.
Contain and remove
Moldy cabinet floors, wet flooring and damaged subfloor are removed inside a small containment so dust does not reach the rest of the kitchen.
Clean, dry and verify
Framing and remaining subfloor are cleaned and dried to normal readings before anything is reinstalled.
Add protection
Consider a leak sensor, a drip tray under the sink, and braided supply lines with quarter-turn valves.
General information for Wheat Ridge, not a quote or professional advice. In an emergency, call 911.