Leak Under the Sink in Your Costa Mesa Home? Drain, Supply Line or Old Pipe in the Wall
A wet cabinet floor can come from a loose drain nut, a tired supply hose or an aging copper stub-out. How to find which one it is in Mesa Verde, Eastside and Westside…
A swollen cabinet floor or a musty smell under the kitchen sink is one of the most common plumbing complaints in Costa Mesa. Most of these leaks are small and easy to fix. Some are an early warning that the pipe inside the wall is wearing out. A few minutes of detective work tells you which kind you have.
Start with a dry towel test
Empty the cabinet, dry every surface and lay a paper towel flat on the cabinet floor. Then check each part one at a time:
- Run the faucet with the drain stopper open. Drips that appear only now point to the drain, the P-trap or the garbage disposal.
- Fill the sink and release it. A leak under heavy flow often comes from a loose slip nut or a cracked basket strainer.
- With the faucet off, wipe the supply lines and the shutoff valves. Moisture that comes back without any water running is pressure-side, and that deserves faster attention.
Common culprits
- Slip nuts and washers on the P-trap that loosen over time.
- Braided or older plastic supply lines that weep at the crimp.
- Angle stops with worn packing that drip at the stem when turned.
- Faucet base seals that let splash water run down into the cabinet.
- Dishwasher or refrigerator connections that share the same space.
When the problem is inside the wall
Many Mesa Verde and Eastside homes were built in the 1950s and 1960s, and plenty still have original galvanized steel or early copper behind the sink. If the dampness starts at the point where the pipe comes out of the wall, or the drywall around the stub-out feels soft, the leak may be in the line itself. Rusty threads on galvanized nipples and green crust on copper stub-outs are signs of corrosion that tends to repeat elsewhere in the house.
What to do right away
Close the angle stop under the sink, or the main shutoff if the valve will not turn. Put a shallow pan underneath and leave the cabinet doors open so it dries. Mesa Water District customers can also read the meter with all fixtures off to see whether water is still moving somewhere else.
Fix the part or plan ahead
A loose nut or a worn supply line is a quick repair. Repeated leaks at different sinks, low pressure and discolored water usually mean the piping is near the end of its life. In that case, a whole-house PEX-A repipe replaces the stub-outs, shutoffs and supply lines at every fixture at once, with a City of Costa Mesa permit and inspection.
Related reading
If your water bill jumped too, read about a high water bill and hidden leaks, or see how PEX repiping works. Neighbors can visit Newport Beach, Irvine and Tustin, or see all of our service areas at repipeinc.com.
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Repipe OC, 23821 Hillhurst Drive, Laguna Niguel, CA 92677, (949) 524-2362, CSLB #1087885 C-36.
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Written by Repipe OC · CSLB #1087885 C-36 · 23821 Hillhurst Drive, Laguna Niguel, CA 92677 · (949) 524-2362