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How to Fix a Leak Under Kitchen Sink: A Step-By-Step Guide

How to Fix a Leak Under Kitchen Sink: A Step-By-Step Guide

Discovering how to fix a leaky kitchen sink can save you both time and money. It’s frustrating to find water pooling under your sink, especially when you’re already tired from a long day. While the immediate solution might be to lay down towels and call a plumber, you’d be surprised how easy it can be to fix a leak yourself.
This guide will walk you through the steps to tackle the problem head-on, so you can get your kitchen back to its best without waiting for professional help. Keep reading to become your own handyman.

Find Leak Under Sink

Assess the Situation

The first indication of a leak is usually finding water soaked into your cabinet or flooding your floor. The first thing you need to do is find out where it’s coming from. Look at where the standing water or dampness is located, then look right above it.
In most cases, this location is where the leak is coming from. Next, you’ll need to find out what kind of leak is occurring to determine how to fix it.

Determine the Type of Leak

If the leak is coming from a pressurized pipe, you’ll likely find water spraying everywhere or far away from the source (these often require professional help).
If it’s due to the seal around the drain, you might not notice until the sink is full of water and slowly leaking out the bottom.
If the leak is from the drainpipe, you’ll have a pool of water at the bottom of your cabinet.
Check all areas around the sink to find out what kind of leak you have, then proceed with the appropriate steps. Leak detection is the most important part of the process.
Type Of Leak Under Sink

Tools and Materials You’ll Need

Before diving into the repair, gathering all the tools and materials you’ll need is essential. This ensures a smooth and efficient fixing process. Here’s a rundown of what you might require:

Basic Tools

  • Adjustable Wrench: This is a must-have for tightening and loosening nuts and bolts. Make sure to have one that can adjust to different sizes.
  • Pliers: Useful for gripping small objects and can come in handy when removing old parts like seals or O-rings.
  • Screwdriver: A standard flat-head screwdriver can be useful for loosening screws on clamps or other fittings.
  • Pipe Wrench: A pipe wrench can provide the leverage you need to tighten or loosen larger fittings for larger plumbing jobs.
  • Bucket: Always keep a bucket handy to catch any water that may spill when disassembling parts.
  • Towels or Rags: These are essential for cleaning up any water that spills and drying off areas before you start your repair.

Specialized Tools

  • Pipe Thread Sealant or Plumber’s Tape: These help to create water-tight seals on threaded pipe connections.
  • Pipe Cutter: If you need to remove a section of damaged pipe, a pipe cutter can make a clean cut.
  • Teflon Tape: Useful for sealing threaded joints and is easier to disassemble than other sealants.
  • Plunger: Sometimes, a simple blockage is the cause of a leak, and a plunger can often solve the problem quickly.


  • Replacement Seals and O-rings: Always good to have on hand in case the existing ones are worn out or damaged.
  • Rubber Gaskets: These can wear out over time and may need to be replaced to ensure a good seal.
  • PVC or Copper Pipes: Depending on your plumbing, you may need extra pipe material if you have to replace a damaged section.
  • Pipe Clamps or Hose Clamps: These can be used to secure loose connections temporarily until you can replace the damaged parts.
  • Adhesive or Epoxy: Some repairs may require a strong adhesive to seal gaps or cracks.


  • Gloves: To protect your hands, especially if you’re working with any chemical sealants or cleaners.
  • Flashlight: For better visibility when you’re working under the sink.
  • Safety Goggles: To protect your eyes from any debris or splashing water.

A person in a black cap and gloves uses a thermal imaging device to inspect pipes under a sink cabinet filled with stacked kitchen containers, ensuring thorough Florida Restoration.

Fix the Problem

The solution or fix for the leak depends on the type of leak. In this section, we’ll break down what types of leaks require what steps for a fix.

Faucet Leaks

Sometimes the faucet is the source of the problem, rather than the drain or seal. Always check the faucet first, since it’s the easiest kind to find.
The good news is that these kinds of leaks are extremely easy to see because they flow down the back of the faucet and pool water behind the sink. In this case, all you need to do is replace the faucet itself.

Drain Seal Leaks

The next thing to check is the drain seal. You’ll know it’s broken if your sink cannot hold water without leaking. It’s very simple to replace as well:

  1. Gently remove the old drain seal with a pair of pliers. If you don’t have pliers, you may use a fork.
  2. Carefully apply new adhesive around the bare drain. Be careful not to apply too much.
  3. Replace the seal, making sure to apply it centered around the drain.

Drain seal leaks are not uncommon or difficult to fix. In fact, you can find replacement parts for the seal at your local hardware store for less than $5. Just make sure to apply it correctly so you don’t need to reapply it later.

Drain Leaks

If you’re sure it’s not a faucet or a seal leak, check if the problem is the drain itself. These happen when water comes out of the drain itself while the sink is emptying, resulting in a cabinet full of water. Most of the time, this is a very easy fix and you just need to tighten the nut for the pipe.
If you’ve tightened the nut and the sink still leaks, take these next steps:

  1. Verify that Plumbers Putty was used when installing the drain outlet flange.
  2. Ensure that the gasket/rubber sealing washer is completely flat.
  3. If everything looks okay and the sink is still leaking, take the entire thing apart and inspect every part to see if it’s cracked or damaged. Replace any damaged parts, then reinstall it.

If these steps don’t work, double-check to make sure the leak is coming from the drain or elsewhere.

Frequently Asked Questions

How often should I check for leaks?

Inspecting under your kitchen sink at least once a month is a good idea. This routine check can help you catch any minor issues before they become major problems. If you’ve had leaks, check more frequently.

What should I do if the leak persists after trying to fix it?

If you’ve followed all the steps and the leak persists, it’s time to call a professional. Persistent leaks can indicate a more serious underlying issue that may require specialized tools or expertise to fix.

Are there any signs of a leak that I should know before it becomes problematic?

Yes, there are early warning signs. These can include a musty smell under the sink, dampness on the bottom of the cabinet, or a higher-than-normal water bill. If you notice any of these signs, it’s best to investigate immediately.

What are the common reasons for a kitchen sink to leak?

Common reasons can include worn-out seals, loose connections, or damaged pipes. Sometimes, the issue could be with the faucet or the water supply line. Regular maintenance can help prevent most of these issues.

Can I use regular household items to fix a leak?

While some DIY fixes suggest using household items like tape or rubber bands, these are usually temporary solutions. For a more permanent fix, using proper plumbing materials like plumber’s tape, rubber gaskets, or new O-rings is advisable.

How do I know if I need to replace parts or if tightening them will suffice?

If the parts are visibly damaged or corrupted, they will likely need to be replaced. However, if everything looks intact and the leak is minor, try tightening the connections first. If that doesn’t work, then consider replacing the parts.

Is it necessary to turn off the water supply when fixing a leak?

Yes, turning off the water supply is crucial to prevent any accidents or further damage. This is a basic safety measure you should always take before starting any plumbing work.

What tools should I have on hand for a quick fix?

Basic tools for fixing a leak under the sink include adjustable wrenches, pliers, a bucket, towels, and a plumber’s tape. Having these readily available tools can save you time when locating and fixing a leak.

How long does it usually take to fix a leak?

The time it takes can vary depending on the complexity of the leak. Simple leaks like a loose nut or a worn-out O-ring can often be fixed in under an hour. More complicated issues may take longer and could require professional help.

We’re Here to Help You With Repairs

Leaky sinks may seem like a huge hassle, but fixing them yourself doesn’t have to be a huge ordeal. A DIY approach is usually enough to fix it, even if you don’t have any experience in plumbing. However, if you can’t manage to fix it with the tips given here, you can always call an expert at All Dry USA!


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