The short answer
Prepare the Cabinet
Empty everything from under the sink so you have a clear view and a clean work area. Place a dry towel or paper towels on the cabinet floor. This gives you a visible marker for any new moisture that appears.
Make sure the area is well lit. A small flashlight or a work light helps you see the back corners where leaks often hide. If you have a slow drip, the towel will show a wet spot that tells you exactly where to look.
- Remove all stored items and cleaning supplies
- Lay down a dry, light-colored towel
- Use a flashlight to inspect dark corners
- Keep the cabinet door open for easy access
Check Every Connection
Trace the water supply lines from the shutoff valves to where they attach to the faucet. Feel each connection with your fingertips. A leak can be a slow drip that only shows as a damp film, not a steady stream.
Inspect the drain pipe, including the P-trap and the slip nuts that hold it together. Run your hand along the underside of the trap. Also check the gasket where the drain pipe meets the sink basin, as this is a common spot for small leaks.
- Water supply line connections at the valve and faucet
- The P-trap and its slip nuts
- The gasket where the drain meets the sink
- Any flex hose or adapter fittings
- The base of the faucet where it meets the counter
Test with Running Water
Turn on both the hot and cold water taps fully, then let them run for about a minute. Watch the connections and the drain pipe while the water flows. Look for drips, spraying, or any change in the moisture on your towel.
Next, close the drain stopper and fill the sink basin halfway. Let the water sit for a few minutes, then release the stopper. This tests the drain seal and the pipe joints under the weight of standing water. Check the towel again for any wet spots.
Inspect for Slow Drips
A leak may not show up right away. After running the water, dry the towel and the pipe surfaces completely. Then wait a while and check again. Feel the connections and the bottom of the P-trap for any dampness.
For a more thorough check, leave the towel in place overnight and inspect it the next morning. A small wet patch indicates a slow leak that needs attention. If you live in Daytona Beach, the humid climate can make it hard to tell condensation from a true leak, so the dry towel method helps.
Know When to Call the Pros
If you find a leak, turn off the shutoff valves under the sink to stop the water flow. You can often fix a loose slip nut or a worn washer yourself. But if the leak is inside the wall, under the cabinet floor, or in the supply line, you need professional help.
Local water damage pros can locate hidden leaks and dry out any moisture that has already soaked into the cabinet or subfloor. They use moisture meters and other tools to find the full extent of the problem. Catching a leak early prevents mold and structural damage.
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Water keeps spreading into floors and walls, so it is worth acting early. Calls are answered 24/7.
Call Now (386) 272-5697Frequently asked questions
How often should I check under my sink for leaks?
Check at least once a month, especially if you have older pipes or a garbage disposal. A quick visual and touch check takes less than five minutes. Also inspect after any plumbing work or after a heavy rainstorm, as shifts in the ground can loosen connections.
What should I do if I see water under the sink?
Turn off the shutoff valves immediately to stop the flow. Wipe up the water and dry the area thoroughly. Then trace the leak to its source if you can. If the leak is from a loose connection, you may be able to tighten it. Otherwise, call the pros for help.
Can condensation be mistaken for a leak?
Yes, especially in humid climates like Daytona Beach. Cold water pipes can sweat in warm, humid air, creating moisture that looks like a leak. To tell the difference, dry the pipe completely and check again later. If the moisture returns only on cold pipes and not on connections, it is likely condensation.