What Causes My Kitchen Sink to Leak? Here are 7 Likely Reasons

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In any home, sinks are one of the most used areas. Its many benefits are its ability to wash dishes, take water for a cup, or fill a carafe with coffee. A leaky kitchen sink can be a frustrating experience as it interferes with the main functions of the kitchen.

A leaky sink can inconvenience every household! Dealing with pesky puddles or hearing that noise is annoying. You may even be more frustrated if you don’t know why it happens!

You may need to determine the source of the leak causing your kitchen sink not to drain. If you attempt the short-lived temporary fix instead of addressing the leak in the first place, you will have a more permanent solution.

It is possible to repair some sinks with leaks, but some require the services of a professional plumber. In addition to calling a plumber or attempting to fix your leaky kitchen sink yourself, you need to understand the cause of the leak.

According to our research, these are the top seven reasons for kitchen sink leaks:


What Causes My Kitchen Sink to Leak? Here are 7 Likely Reasons


1. Water Supply Line may have leaks

It may be a problem with the faucet’s supply lines for water if the water leak under your kitchen sink is constant. Water supply lines for a sink typically have two, though there could be three if your sink has a separate sprayer. A burst water supply line can cause issues.

Because the connections are usually away from your view and hidden from view, you might not be able to see the leak until it’s soaked the cabinet and everything else under the sink storage.

The leak in the water line could result from corrosion, or more often, it is due to a ruptured gasket inside the connector. In most instances, replacing the gasket would suffice to stop the leak; however, tightening the connections will work in some cases.

2. Faucet Leaks

It is usually easy to identify leaks at the source of the water. Water pools at the top of the sink when one turns on the water. You can also find a leak under the sink, so you will only notice it if you look under the counter.

Worn-out washers or gaskets cause most faucet leaks. All you need to do is replace the gaskets or washers. Depending on the severity of the leak, the faucet may need to be completely replaced. This is not a problem.


What Causes My Kitchen Sink to Leak? Here are 7 Likely Reasons


3. P-Trap may be clogged

A “P-trap” is a curved section of a pipe beneath the sink. By blocking drains from entering unpleasant odors, it serves its primary purpose. In most cases, the P-trap is hidden from view, making it difficult to detect problems immediately.

Small pieces of food and gunk will accumulate around the P-trap with time. As a result, water does not drain efficiently, leading to leaks. The sink could also be corroded if it’s made from metallic materials. When this happens, it will need to be replaced completely.

4. Leaks in Drains

Kitchen sink leaks may be the result of a clogged drain. To prevent leaks, drains are typically lined with plumber’s glue. Nonetheless, the putty may be too thin initially or may dry out over time. There are times when leaks are caused by worn-out drains that can’t be repaired. It is best to contact a plumber in such situations and completely repair the drain.

Plug your sink using the drain cover, then fill it to the top, and then unplug it. Look around under the sink with a flashlight to determine what is causing the issue.

Some problems can be fixed by tightening the nuts at the junction of the two pipes. However, in other instances, plumbers’ glue is necessary. You can remove the drain, repackage it with a new plumber’s putty, and then reconnect it.


What Causes My Kitchen Sink to Leak? Here are 7 Likely Reasons


5. Seat for the Valve

In order to compress the mechanism, the valve’s seat acts as a connector between the spout and faucet. Adding water to the valve seat may corrode, causing the region around the spout to leak. An experienced plumber should regularly clean the valve seat.

6. O-ring may be Loose

The tap handle is held in position by a stem screw. Known as an O-ring, it is attached to a small disc. A leak around the O-ring is the most common cause of kitchen sink leaks. With time, the O-ring wears out or becomes loose, causing the faucet to leak near the handle. Replace the O-ring if it has been broken. It is often the most damaged part. Usually occurs with cartridge faucets.

7. Washers that are Worn Out

A damaged washer causes most leaky sinks. The washer is pressed against the valve’s seat on this faucet every time you turn it on. When the washers deteriorate due to constant friction, you’ll start to see water leaks around the spout. A worn out washer can cause sink leaks, which can be repaired by changing the washer. Wearing out washers are common with compression faucets.



A leaky kitchen sink can be so frustrating, especially if you’re having trouble diagnosing the cause. Cleaning up the water won’t do much if you don’t know how to fix the leak. To stop the leak, you need to repair or replace the leak.

The next time your kitchen sink begins to leak, and you’re not sure what to do, call a professional plumber from Caldwell Plumbing.

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