Water Under the Kitchen Sink? How to Find the Leak in Arlington

Water under the kitchen sink usually comes from one of six spots: the drain trap, the sink strainer, the faucet base, the supply lines, the shut-off valves or the dishwasher hoses. A leak that only shows up when you drain the sink points to the drain. One that drips all the time points to the supply side. If every part is dry but the cabinet stays wet, the leak may be in the wall. Call (817) 285-5426 for help.

When the cabinet stays wet and you cannot find the drip, call our team for leak detection Arlington TX with acoustic and thermal tools.

Where do kitchen sink leaks start?

The six common spots are the P-trap and slip nuts, the basket strainer seal, the faucet base and sprayer hose, the braided supply lines, the angle stop valves and the dishwasher drain and supply lines. Each leaves a clue about where it drips and whether it leaks with the tap on or off.

How do I find which part is leaking?

Empty the cabinet, dry everything and lay paper towels on the cabinet floor. Then test one part at a time: look at the supply side with no water running, run the faucet, fill and drain the sink, then run a short dishwasher cycle. The first paper towel that gets wet points to the leak.

1. Supply test. With no water running, wipe the valves and supply lines. Wet means a supply leak.
2. Faucet test. Run the tap for a minute and check the base and sprayer hose.
3. Drain test. Fill the sink halfway, pull the plug and watch the strainer and trap.
4. Dishwasher test. Run a short cycle and watch the drain hose and air gap.
5. Disposal test. Check the bottom and side of the garbage disposal with a flashlight.

Hand-tighten loose slip nuts first. Do not crank them with a wrench, which can crack plastic parts.

What if all the parts are dry?

If every part under the sink stays dry but the cabinet floor or back wall is damp, the leak may be in the wall, under the floor or from the fridge or dishwasher line nearby. A soft cabinet floor, stains on the back panel, a musty smell or a swollen baseboard next to the cabinet are the clues.

In many Arlington homes the kitchen supply lines come up through the slab. A leak there can show up first at the sink cabinet. Read the slab leak signs and our guide to appliance water line leaks. A musty smell near the cabinet is also worth checking.

Can a slow sink leak cause bigger damage?

Yes. Most sink cabinets have a particleboard floor that swells and crumbles when wet. Water then reaches the subfloor or slab edge, and mold can start in a few days. A supply leak also runs all day and adds to your water bill. Fixing it early is almost always cheaper.

To stop water fast, close both valves under the sink. If they will not close, use the main water shut-off valve.

How much does it cost to find a hidden sink leak?

A loose nut or worn supply line is a small fix. When the leak is inside the wall or slab, basic leak detection in Arlington runs about $150 to $400, and slab leak detection about $250 to $600. You get the price before work starts.

General estimates for Arlington, TX in 2026. Your exact price is confirmed before any work begins.