First: Stop the Water and Empty the Cabinet
Pull everything out of the cabinet and set it on a towel. Then look for the two small valves on the wall or floor of the cabinet where the supply lines come in. Turn them clockwise until they stop. If a valve will not turn, or turns and water keeps coming, do not force it. Old valves in Valley homes are often seized by mineral scale, and snapping one off turns a drip into a flood. Turn the water off at the main instead.
Dry the cabinet floor, the pipes and the walls with towels and leave the doors open. A fan pointed into the cabinet helps. The goal is to get the wood dry within a day or two, because particleboard cabinet floors swell and crumble when they stay wet.
Take a photo of the inside of the cabinet before you dry it. It is useful later for us, and for your insurance if it turns into something bigger.
Finding the Source
With the cabinet empty and dry, turn the water back on and run the faucet while watching with a flashlight. Then plug the sink, fill it, and let it drain while watching again. Leaks show up at different moments depending on the source.
Water that appears as soon as the valves are open, even with the faucet off, is a supply side leak: the valve itself, the compression nut, or the braided supply line. Water that appears only when the faucet runs is usually the faucet body or the connection under the faucet, which drips down the lines. Water that appears only when the sink drains is the drain side: the basket strainer, the tailpiece, the trap nuts, or the disposal.
A leak that appears only when the dishwasher runs is the dishwasher drain hose or its connection to the disposal or the drain. A leak that seems to come from nowhere, with the cabinet wet at the back wall, can be a sprayer hose, a reverse osmosis unit, or in some cases the sink rim where caulk has failed.
- Wet with faucet off: supply valve, nut or line
- Wet only when faucet runs: faucet body or its connections
- Wet only when draining: strainer, tailpiece, trap or disposal
- Wet only when dishwasher runs: drain hose or clamp
- Wet at the back wall or rim: sprayer hose, RO unit or sink caulk
Why Valley Homes See These Leaks
Hard water is the common thread. Scale builds up inside shutoff valves until they seize or weep. It crusts on faucet cartridges until they drip. It corrodes the chrome on older supply nuts. Add summer heat in a closed cabinet, which dries out rubber washers and plastic trap nuts, and a twenty-year-old kitchen in Peoria or Glendale is simply due for a few of these parts.
The other common cause is a repair that was done with the wrong parts. Slip-joint trap nuts that were overtightened and cracked, supply lines that are too short and pulling at an angle, or a disposal that was hung without resealing the flange. These show up months later as a slow drip.
What a Handyman Repair Usually Involves
The parts themselves are inexpensive. A pair of quarter-turn shutoff valves, braided stainless supply lines, a new trap assembly or a basket strainer are all common stock. The work is in doing it cleanly so it does not leak again: cutting out a seized valve, cleaning the pipe, installing the new valve correctly, and testing under pressure.
We replace old multi-turn valves with quarter-turn ball valves whenever we are in there, because they are far less likely to seize in hard water and they are the kind you can actually shut in an emergency. We also replace rubber supply lines with braided stainless, since the rubber ones are the most common cause of the big floods.
If the faucet itself is the source, replacing a cartridge is possible on some models, but on older or builder-grade faucets a replacement faucet is often the better value. We can install one you have chosen or recommend one.
Dealing With the Cabinet Damage
If the cabinet floor is swollen, soft or delaminated, it can be replaced without replacing the cabinet. We cut out the damaged floor panel and fit a new one, often with a water-resistant surface. If the side panels or the toe kick have wicked water, those sections can be repaired too. The drywall behind the cabinet is worth checking if the leak ran long enough to reach it.
Mold is the concern with any leak that went unnoticed for weeks. Small areas on hard surfaces can be cleaned, and the EPA guide linked below explains what homeowners can handle themselves. Soft materials that have grown mold, such as a particleboard floor, should be removed rather than cleaned.
Our water damage repair service covers cabinets, drywall and flooring once the leak itself is stopped. We will tell you honestly if what we find is beyond a handyman repair and needs a restoration company.
Preventing the Next One
Once a year, empty the cabinet and look. Run your hand along every line and nut. Open and close each shutoff valve so it does not seize. Replace any supply line that is more than ten years old or is rubber. Keep a battery water alarm on the cabinet floor; they are inexpensive and will wake you up before the floor does.
If you have a reverse osmosis system, check its fittings and the tank, since those small plastic lines are a frequent source of slow leaks. And when any new fixture or appliance is installed, ask for the old valves to be replaced at the same time if they are the multi-turn type.
- Annual look with a flashlight and your hand on every joint
- Exercise the shutoff valves so they do not seize
- Braided stainless supply lines, replaced every ten years
- A battery water alarm on the cabinet floor
- Quarter-turn valves installed with any new faucet or disposal
When to Call Right Away
Call the same day if you cannot shut the water off, if water is coming from inside the wall rather than a fitting, if the leak is on a hot water line and you cannot stop it, or if the floor outside the cabinet is wet. Those are the situations where the cost is rising by the hour.
For a drip you have contained, a photo and a description are enough for us to bring the right parts and fix it in one visit. Most under-sink repairs, including new valves, supply lines and a trap, are done in an hour or two.
“Nathan did a great job of cutting and finishing the exterior wood beams on my home. He remove the rotted wood and sealed and painted and they look so much better. He worked in the blazing sun without complaint, nice guy and talented craftsman. Highly...”