How to Fix a Leaking Kitchen Sink with Seven Common Reasons

The kitchen sink is easily the most used area of your house. We use it to wash the dishes, get a drink, make a cup of coffee and so much more. So experiencing a leak in the kitchen sink can be a stressful experience because it puts a stop to so much functions.

When you are looking at how to fix a leaking kitchen sink the first place you need to start is to establish the cause. The best course of action is to fix the problem with the leak at the source rather than apply a short term fix that needs attention again later on. Some leaks can be fixed by you while others will need a professional plumber. No matter which way you choose to go it’s still important to understand what is causing the leak.

In this article we are looking at seven of the most common causes for kitchen sink leaks, plus what you can do to fix them.

1 – Drain Leaks

Your kitchen sink drain could be be a reason why it’s leaking. Drans are typically sealed with plumber’s putty which prevents the kitchen sink leaking. However, the putty may be too thin when it was applied or it has dried in your sink drain.

Sometimes the leak can stem from the drain just being old and worn out, which means it will need to be replaced. A plumber is usually the best person if the drain needs to be replaced completely. If it just needs some more plumber’s putty you can usually do it yourself.

To find out where the kitchen sink leak is coming from then you need to plug up your sink and then cover the drains. Fill it to the top then take the plug out. Pop your head underneath the sink and use a flashlight to have a look and see why it’s leaking.

Hopefully you will be able to fix your leaky kitchen sink by tightening up the nuts which are where the pipes joining together. More putty could also do the job.

2 – Faucet Leak

Leaks that are coming from the faucet tend to be a lot easier to spot. One common sign you should look out for are water puddles that form at the top of the sink whenever the faucet is turned on. The faucet can also cause the sink to leak underneath as well so you’ll only spot this by looking under the counter.

In most cases a faucet leaking is caused by worn out washers or gaskets. It’s simple to replace these. A severe leak may mean you need to replace the whole faucet but this also isn’t difficult to do.

3 – Water Supply Connection is Loose

A kitchen sink leaking underneath constantly means there could be a problem with the water supply line. Your standard kitchen sink will come with two water supply connections, but if you have a sprayer then there could be three. Each of these connections could spring a leak at any time and cause you problems.

The connections are pretty much out of sight so you won’t notice your kitchen sink leaking undtil it’s soaked everything. Water line leaks underneath the sink are often due to failed gaskets and corrosion. Replacing the gasket could be enough to stop the kitchen sink leaving but you may need to tighten the connections as well.

4 – Clogged P-Trap

The P-trap is the curved part of the pipe that can be found underneath the sink. It’s there to prevent horrible smells from forming and then seeping out of your drains. P-trap leaks can be harder to identify because they are placed out of sight.

Because the P-trap acts a sink strainer, over time pieces of food and other gunk can gather there. This will then stop the water from draining properly and can cause leaks. Metal parts can also corrode and cause problems, which would mean you need to replace the trap entirely.

5 – Damaged O Rings

The small disc that is attached to the faucet handle screw is called an o ring. It’s very common for kitchen sinks to occur here. Over time the o rings can become worn out, especially with regular use which makes the faucet leak from the handle. If the o ring is damaged then replacing it with a new one should stop the kitchen sink leaking. O ring problems mostly happen in faucets that have a cartridge.

6 – Worn Out Washers

Probably the number one reason for a kitchen sink leak is a worn out washer. Every time the sink is used, the washer presses against the valve seat in the faucet. The friction that this causes over time can cause the washer to wear out and this is when leaks start to spring up around the spout. This is another simple fix by replacing the washers which can normally be done without the help of a plumber. Washers having to be replaced are more common in compression faucets.

7 – Valve Seat Corrosion

The valve seat is the part that connects the spout and the faucet so that the compression mechanism of the tap works. Water that gathers in the valve seat can result in it corroding which will then make the area around the faucet spout leak. Making sure to regularly clean the valve seat with help from your local plumber is definitely advised if you think this may be your issue.


The most important think to remember about leaking sinks is that they should be fixed quickly to prevent any sort of damage happening. No matter the cause there is a solution. Sometimes these can be as simple as applying some plumbers putty or cleaning out the sink strainer fo your garbage disposal. Just ensure tha you get professional help for bigger problems with faucet connection leaks.

We have plenty more articles to help with faucet and sink links as well as drainage issues to ensure you always have fresh drinking water at your disposal. Make sure to check out our other guides here on our website and share our pages with others who may need help.


How do I stop my kitchen sink from leaking?

You can find out reasons why your kitchen sink is leaking from the article above and what you can do to fix problems like this when they happen. There can be several causes for leaking sinks so it’s important to find the root cause so that you can stop it from happening.

Why is my kitchen sink leaking underneath?

If the kitchen sink is leaking underneath this could be a sign there is a leak in the drain itself. Worn out pipes and corrosion can cause fractures in the plumbing lines that run underneath your sink. This would then cause the water flowing down the drain to leak out of the cracks instead.

How do you seal the base of a faucet?

The easiest way to seal the base of a faucet is to use plumbers putty. Apply a ring of it to the bottom of the faucet base around the edges so that the entire base edge is covered. This should then create a watertight seal.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.