Home Plumbing How To Fix Kitchen Sink Leak

How To Fix Kitchen Sink Leak

How To Fix Kitchen Sink Leak

Your kitchen sink assembly consists of various connections. A loose-fitting or damage at any of these connections can lead to a leak. To fix a kitchen sink leak, you will need to make a thorough investigation of your sink assembly and then choose the appropriate solution.

The sink assembly is hidden away in a world of its own below your sink. I personally only open my sink cabinet once a week to grab cleaning supplies. As I grabbed my box of cleaning wipes soaked it water, I was left puzzled as to how that happened. Water has no business being in your sink cabinet. Its job is to follow the path through your pipes and make its way out through the main drain pipe.

What was more puzzling was that nothing other than my box of wipes was wet, which was a good sign. You do not want a pool of water being collected in the cabinet. Over time it can cause damage to your cabinet floor.

To find the answer to my puzzle, I cleared my kitchen cabinet of my cleaning supplies and placed a bucket underneath my sink. Now came the time to wait. I opened my faucet and observed my pipes for the location of the leak. Don’t expect to see water dripping right away; keep observing your pipes for a few minutes. And then you will find the culprit, for me, it was a loose connection between my sink drain and the drainpipe. For you, it could be something else such as your p-trap or the connection to the main outlet.

Once you have found your leak(s), turn off the main water supply valves and get to work fixing your kitchen sink leak.

Average Cost To Fix Kitchen Sink Leak

This is a project that will have varying costs depending on the source and severity of the leak. Your total expense for this project can range anywhere between $20 – $200.

Time Required

It can take between 1-2 hours to fix your kitchen sink leak. You need to carefully observe your connection first to detect the source of your leak and then make the necessary preparations to begin fixing it. Simply tightening connections will take a few minutes, but replacing parts, especially your faucet assembly, requires patience and proper technique. To avoid future leaks, take your time with this project and focus on fixing the problem properly then the time invested.


  • Small slotted Screwdriver
  • Crescent wrench
  • Plumber’s grease
  • Pipe Wrench

Finding the Cause of the Leak

1. Drain Leak

Your sink drain is the primary point of drainage for water. An incorrectly installed kitchen sink drain or an old/damaged sink drain can lead to leaks. There are two leading indicators of a malfunctioning kitchen sink drain. First, you will have a partial or completely clogged sink. Second, water will leak from the drain and into your kitchen sink cabinet.

To fix a drain leak, you will have to replace your kitchen sink drain.

how to fix kitchen sink leak properly

2. Faucet Leak

A leaking faucet is a common sight in any kitchen. Faucets are used hundreds of times every week and undergo severe wear and tear over time. Each time you use the faucet, the washer presses against the valve seat. As a result, there is constant friction against the washer, which leads to it becoming damaged. This will inevitably lead to a leaky faucet, and each time you enter your kitchen, you will be greeted by a constant unrhythmic sound of water dripping into your sink.

Before beginning to replace any part of your faucet assembly, make sure to block the sink drain opening. You can either use a drain cap or place a towel over the opening. The faucet assembly has numerous small parts that you do not want to fall into your sink drain.

To fix a kitchen sink leak caused by worn-out washers follow these steps –

How to fix kitchen sink leak correctly
  • The first step is to open the decorative cap from your faucet, which will easily pry-off using a small slotted screwdriver.
  • Use a screwdriver to remove the handle screw and pull off the handle.
  • Using a crescent wrench, unscrew the packing nut.
  • Then use an adjustable wrench to loosen the stem from the faucet body.
  • The rubber washer will be located at the bottom of the stem.
  • Remove your old washer and attach the new one. The washer simply needs to be placed onto the grooved surface of the stem.
  • We recommend coating the washer with plumber’s grease. It improves the washer’s durability.

Along with washers, there are other parts of the faucet assembly, which can cause leaks. As you have already dismantled the assembly at this time, check the condition of your O- ring and valve seat.

Replacing the O-ring

An O-ring is a donut, shaped seal that prevents the passing of air or fluid. It creates a seal between your faucet valve seat and the water supply pipe and prevents leaks from faucet handles. Just like washer’s overtime, O-rings wear out and cause leaks.

The O-ring is placed above the washer onto the stem. Apply a coat of plumber’s grease onto the O-ring once you have threaded it onto the stem.

BE MINDFUL: O-rings range in size from 3/8 to 5/8 inch. It is imperative to have the correct size of O-ring. Your faucet’s manufacturer’s instructions will contain the required size of your O-ring.

A Corroded Valve Seat

The faucet seat valve is the primary connection between your faucet and the water supply line. Similar to the O-ring, a faulty valve seat will lead to water leaking from the faucet handle. After dismantling your faucet assembly take note of the condition of the valve stem. If you notice corrosion, you will need to replace it.

As you will see, a faucet assembly has numerous parts, all of which need to be in good condition to prevent leaks. If you notice that multiple parts of your faucet assembly are worn out, it will be cost-effective to replace your kitchen sink faucet.

3. Loose Water Supply Connection

Apart from your kitchen sink drain and faucet, other connections can also cause a leak. A close observation of all your sink connections is needed to identify and fix your kitchen sink leak.

Some of the main connections in the sink assembly include –

  • Sink drain’s connection to the drainpipe
  • Drain pipe’s connection to the P-trap
  • P-trap’s connection to your main outlet (attached to your wall)

Open your faucet and let the water flow through your drain. Observe and look for any leaks from the connections mentioned above. Once you have identified the source of your kitchen sink leak, follow these steps to fix –

  • Close your faucet and wait for the water to drain from the pipes.
  • Use a cloth to wipe the leaking connection
  • Using a wrench tighten the slip-nuts at the connection.
  • Open the faucet and check the connection for leaks.

Important Tip: Do not overtighten the slip-nuts. If the slip-nut is faulty, you will need to replace it or the part itself. Overtightening will not fix the leak and can lead to further damage to the pipes.

4. Clogged P-trap

The P-trap, as the name suggests, is a P-shaped pipe that is connected to your drain pipe. A clogged P-trap can lead to sink clogs and leaks. Over time, the P-trap can become clogged due to the collection of debris and waste. If your P-trap is clogged, you’ll need to clean it. Don’t worry; it is a quick and straightforward process.

How to fix kitchen sink leak properly
  • Place a bucket underneath the P-trap before you start to collect any water that will drain once you open it.
  • The P-trap has two primary connections, one to the drainpipe coming from the sink and the other, the main drainage pipe located in your wall. You will need to unscrew both.
  • Start by removing the slip nut connected to the drainpipe followed by unscrewing the slip nut between the P-trap and the trap arm.
  • Lastly, unscrew the nut at the bottom on the waste tee to completely remove the P-trap assembly.
  • Remove the collected waste using gloves and proceed to wash the pipes with soap and water to clean them thoroughly before re-installing.
  • While re-installing the P-trap be mindful about not over-tightening the slip nuts.
  • Open your faucet and inspect the connections for leaks.

Frequently Asked Questions: How To Fix Kitchen Sink Leak

Do I need to replace my faucet due to a faulty washer?

No, replacing a faulty washer will prevent your faucet from leaking. Only if multiple parts of the faucet assembly are damaged you should consider buying a new faucet.

Can there be multiple leaks at the same time?

Yes, that is why before starting to replace any parts you should take the time to identify all the leakages on your sink assembly.


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