How to Fix Water Damage Under Kitchen Sink

Did you know that a tenth of American households have leaks that waste around 90 gallons of water a day? Can you believe that?

And what is one of the most common types of water leaks in homes?

You’ve guessed it – kitchen sink leaks.

These leaks, if untreated, can lead to higher water bills and mold. Mold also means more bills in terms of what you would spend on remediation services.

So, let’s avoid that. Today, we’ll cover what causes kitchen sink leaks, signs of a leaking kitchen sink, and how to fix a kitchen sink leak. 

Here we go!

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kitchen sink leak

Signs of a Leaking Kitchen Sink

I’m unsure if I have a kitchen sink problem. How do I know?

Okay, so here’s a list of things to look for:

  • Visible puddles of water around the base of the sink or on the cabinet floor.
  • Sounds of water drips or continuous dripping noise beneath the sink.
  • Water stains or discoloration in the cabinet base or on the surrounding walls
  • Mold or mildew in the same space accompanied by musty or damp smell
  • Corrosion on pipes or fittings under the sink.
  • Sudden spikes in water bills without a corresponding increase in usage.
  • Reduced water pressure in the sink faucet
  • A leak can affect the efficiency of your water heater, leading to less hot water.
  • Foul odors rising from sink drains
  • Insects or pests around the sink

But, honestly, you should be able to easily spot a kitchen sink problem. It’s not like a basement where leaks may easily go unnoticed for weeks or even months.

We use our kitchens every day and a leak would likely be spotted, if not right away, then shortly after.

Nevertheless, look for these signs and then move on to the following steps. 

Causes of Kitchen Sink Leaks

Before we proceed to the techniques of how to mitigate a leaking sink, you first need to know what caused it.

Here are the potential perpetrators:

  • The seals around the sink’s edges or between the sink and the countertop may degrade and, over time, allow water to seep through.
  • Loose or improperly connected faucet components, such as nuts or washers. Deez nuts!
  • Connections between pipes, especially under the sink, may develop leaks due to corrosion, wear, or improper installation.
  • A cracked sink basin, especially if it’s made of materials like porcelain or ceramic.
  • O-rings within the faucet assembly may have worn out.
  • If your kitchen sink is connected to a dishwasher, a faulty connection at the hose may be the source of the problem.
  • Leaks may stem from a damaged or worn-out garbage disposal unit, particularly if the seals or connections are compromised.
  • Blocked or clogged drain lines.
  • The sink may not have been sealed properly during its installation.
  • High water pressure.
  • The P-trap, a curved pipe beneath the sink, could have cracked.
  • In cold climates, water trapped in pipes can freeze and expand, leading to leaks when the ice thaws.

Remember, cleaning up the water won’t deal with the root cause of the problem. It will just temporarily make the situation better.

You need to inspect in and around the sink to find out what really led to a leak and fix THAT. And then the following cleanup won’t be for nothing since the water won’t come back.

And you’ll save some money on water bills!

How to Fix a Leaking Kitchen Sink

So, now, let’s get into the actual steps.

Fixing a leaking kitchen sink can vary depending on the specific issue. Here’s a general step-by-step guide to help you address common causes of leaks:

Tools you’ll need:

  • Adjustable wrench
  • Plumber’s tape
  • Plunger
  • Plumber’s putty or silicone sealant
  • Bucket
  • Towels


  1. Identify the Source of the Leak: Follow the water to locate the source of the leak. Check for everything we’ve mentioned so far.
  2. Turn Off Water Supply: Locate the shut-off valves under the sink or at the main water supply. Turn them clockwise to shut off the water to prevent further water damage.
  3. Empty the Cabinet: Remove any items stored under the sink to have clear access to the plumbing.
  4. Check Faucet Connections: Tighten any loose nuts or connections using an adjustable wrench.
  5. Examine P-Trap: Place a bucket under the P-trap (the curved pipe under the sink) to catch water. Loosen the nuts connecting the P-trap to the sink and the wall. Clean out any debris or things blocking the water flow.
  6. Inspect Sink Basin and Seals: Check the sink basin for cracks. If found, consider applying plumber’s putty or silicone sealant to seal the cracks.
  7. Address Pipe Leaks: If you find leaking pipes, identify the specific joint or connection that’s problematic. If there’s a crack, consider using plumber’s tape or replacing the damaged section of the pipe.
  8. Check Garbage Disposal Connections: If your sink has a garbage disposal, inspect its connections and tighten them.
  9. Inspect Dishwasher Connection: Examine the hose connecting the dishwasher to the sink. Replace the hose if necessary.
  10. Apply Plumber’s Tape: If you find threads on pipes or connections, applying plumber’s tape can help create a tighter seal. Wrap the tape around the threads in a clockwise direction.
  11. Reassemble and Test: Reconnect the P-trap, faucet connections, and any disconnected parts. Turn on the water supply and check for leaks. If any persist, tighten connections further. Then check again. Repeat until successful.
  12. Clean Up: Wipe down the area, remove the bucket, and return items to the cabinet.

If you’re uncertain about any step or if the issue persists, it’s advisable to seek professional help from a plumber to ensure a proper and lasting solution.

On the other hand, if you can’t cleanup and fix the water damage from a leak (damp and moldy walls, soaked-up carpets or hardwood floors, etc.), call a restoration company instead.


And there ya go! That wraps it up. Hopefully, you’ll be able to fix that kitchen sink and prevent it in the future.

If you need more help with leaks, check out some of our other posts or connect with a restoration pro near you!

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