Kitchen sink leak: What to Check and What to Do Next

Use only checks that match the exact appliance or system and its official guide.

1. Check 1

   From a dry, stable position, record whether the last visible leak appeared during faucet use, after the basin drained, while the disposal operated, after a sprayer or pull-down hose was used, or while the sink was untouched. Do not repeat the use cycle to test it.

   Expected result: The leak is use-triggered, drain-triggered, disposal-triggered, intermittent, or continuous even when the sink is idle.

   Next step: Stop using the sink if water is active or spreading, and give the trigger history to a plumber. Continue only with visual observations from a dry location.

   Stop if: Stop immediately if the leak is continuous, water is near electrical equipment, or safely reaching the observation area would require stepping into water.

   Why this matters

   Why: Timing separates faucet and hose behavior from drain-side or supply-side behavior, but it does not prove which hidden connection has failed. A continuous leak is more urgent because water may continue without a new sink use.

2. Check 2

   Look without touching for the highest visible wet point and note whether moisture is at the faucet base or handle area, sink rim, drain opening, disposer or drain connection, supply connection, cabinet side, or floor. Photograph the location and surrounding dry surfaces.

   Expected result: Water is visible above the counter, below the sink basin, at a drain or supply area, along the cabinet wall, or only on the floor.

   Next step: Keep the area unused and provide the photos and highest visible point to service. Do not remove a cabinet base or plumbing to chase the source.

   Stop if: Stop if water is pooling, the cabinet floor is soft, the source is hidden, or any electrical or disposal equipment is wet.

   Why this matters

   Why: The visible location helps a professional choose between faucet, drain, supply, cabinet, and floor investigations. Water can travel along a surface, so the lowest wet mark is not necessarily the source.

3. Check 3

   From above the counter, look for a visible wet ring at the faucet base, moisture under a handle, water at the sink rim, or water appearing only when the faucet is in a particular ordinary position already observed. Do not remove the handle, sprayer, cartridge, sink clips, or seal.

   Expected result: Moisture is at the faucet base or handle, at the sink-to-counter rim, around a sprayer hose path, or absent from the upper sink surface.

   Next step: Record the faucet brand or model only if it is already visible without disassembly, then request plumbing service for a model-specific assessment.

   Stop if: Stop if water reaches a counter outlet, appliance, disposal control, or any electrical device, or if finding the model would require removing a part.

   Why this matters

   Why: A faucet-base or handle pattern can indicate a faucet seal or cartridge path; a rim pattern can involve the sink-to-counter interface; no upper moisture makes a concealed or under-sink path more relevant. Exact parts depend on the faucet and sink model.

4. Check 4

   From the cabinet opening or doorway, look for staining, swollen board edges, softened shelving, peeling finish, mold-like spotting, musty odor, or water marks on stored items. Do not kneel in standing water, move a heavy appliance, pull out the disposal, remove panels, or perform cleanup on contaminated water.

   Expected result: The cabinet is dry, has a localized old-looking mark, is actively wet or swollen, has odor or visible growth, or contains water near electrical equipment.

   Next step: Keep people and pets away from the affected cabinet, stop using the sink, and request plumbing plus appropriate water-damage service. Do not demolish the cabinet or apply DIY mold treatment.

   Stop if: Stop at once for standing water, sewage odor, visible contamination, softened flooring, or wet electrical equipment.

   Why this matters

   Why: Cabinet swelling or odor shows that the leak may have persisted or that materials were affected, even if the current source is not obvious. Water near electrical equipment or contaminated water raises the safety and service urgency.

5. Check 5

   Record whether the leak started after a faucet, disposal, filter, hose, drain, or cabinet change; whether it followed a freeze, move, cleaning, or remodel; and whether the home's water supply has been interrupted. From a dry position, note any visibly damaged or corroded connection without tightening, cutting, or disassembling it.

   Expected result: The leak followed a recent change, appears at a visibly damaged connection, recurs without a clear event, or has no known history.

   Next step: Give the timeline, photos, fixture model if known, and whether the leak is ongoing to the plumber. Leave the sink unused until the service decision is made.

   Stop if: Stop once the next step would require turning a hidden fitting, opening a wall or cabinet, cutting pipe, or touching water near electricity.

   Why this matters

   Why: Recent work and visible damage are useful clues for the professional, but neither confirms that a particular fitting or repair kit is compatible. A no-history leak still needs the same trigger and location evidence.