Why Is Water Leaking Under My Kitchen Sink?
Water under your kitchen sink can come from several places, and finding the source quickly can help prevent cabinet damage, mold, and larger plumbing problems. Common causes include leaking supply lines, loose drain fittings, a failing garbage disposal, faucet leaks, or worn shutoff valves.
Start by drying the entire area beneath the sink, including the pipes, cabinet base, and connections. Then run the faucet and watch for where moisture first appears. Ally Plumbing helps Seattle homeowners locate under-sink leaks and determine whether the problem needs a fitting adjustment, part replacement, or plumbing repair.
If water is actively spraying from a supply line, pooling inside the cabinet, or causing swelling or mold, stop using the fixture and address the leak promptly.
Common Causes of Water Leaking Under a Kitchen Sink
Leaking Supply Lines
Supply lines carry hot and cold water from the shutoff valves to the faucet. Connections can loosen, washers can fail, or the line itself can crack.
A supply-line leak may drip slowly or release water quickly under pressure. If you see active leaking, turn off the appropriate shutoff valve if it can be done safely.
Loose or Leaking Drain Fittings
The drain assembly beneath the sink includes several joints and fittings. If one becomes loose or a washer wears out, water may leak when the sink drains.
These leaks are often easier to spot after filling the sink and then draining it while watching the connections below.
Garbage Disposal Leaks
If your kitchen has a garbage disposal, water can leak from the sink flange, dishwasher connection, drain connection, or disposal body.
A leak from the disposal body may indicate internal failure and can require replacement rather than a simple adjustment.
Faucet Leaks
Water from a leaking faucet can travel through the sink opening and appear inside the cabinet. Worn seals, loose hardware, or damaged faucet connections may be responsible.
Shutoff Valve Problems
The shutoff valves beneath the sink can leak around the handle, stem, or connection point. Corrosion and worn seals are common causes.
Signs an Under-Sink Leak Needs Professional Repair
Watch for:
- Standing water inside the cabinet
- Swollen or warped cabinet material
- Musty odors or visible mold
- Active dripping from a supply line
- Water returning after the area is dried
- Corrosion around valves or fittings
Even a small leak can damage cabinets or flooring when it continues over time.
How Much Does Kitchen Sink Leak Repair Cost in Seattle?
Minor plumbing repairs under a kitchen sink frequently fall in the low hundreds. The final price depends on the failed component, parts required, accessibility, and labor.
Tightening a fitting or replacing a small seal may be straightforward, while a damaged faucet, garbage disposal, shutoff valve, or supply line can require additional work.
Get Kitchen Sink Leak Repair in Seattle
If you find water under your kitchen sink, dry the area first and identify where moisture returns. If the source is not obvious or the leak continues, professional diagnosis can help prevent further damage.
Ally Plumbing provides kitchen sink leak repair for Seattle homeowners. Call (844) 669-ALLY to schedule service and have the leak properly diagnosed before it causes cabinet, flooring, or moisture damage.
