How to stop your kitchen sink leaking

The 'drip, drip' of a kitchen sink leaking is frustrating - but we can help. Read on to discover how to fix a leak under the kitchen sink with our simple guide.

Updated 9 June 2022


AuthorBy Cleanipedia Team

Reading Time5 minutes

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A leak under the sink needs attention as soon as possible but sometimes it's difficult to tell where the leak is coming from or how to fix it. Here you can find a step-by-step process for how to identify the source of a leak under your sink, which sorts of leaks are easy to fix yourself, and when it's time to call in a plumber instead.

You might think water doesn't leave stains behind, but it can – and there's a trick to removing them. Check out this article on cleaning up water stains after the leak is fixed.

How to fix a leak under the sink in your kitchen: A step-by-step guide

When you discover that you have a sink leaking it's important to get it sorted quickly before it causes too much damage. Whilst some situations require a plumber, there are some leaks which you can easily fix at home. Read on to discover our guide for what to do if your kitchen sink is leaking. 

If your kitchen sink is leaking underneath, you first need to identify what is causing the leak. Start by clearing out the area under your sink and then check for the following:

  1. 1

    A pressurised water hose leak. Have you got a constant spray? This is likely the cause. You'll probably find it creates a rather large mess due to its constant flow.

  2. 2

    A drain line leak. If you turn your tap on, and as the water drains away the pipe under sink is leaking, this could be the culprit.

  3. 3

    A faulty seal or drain gasket. If it is neither of the two above issues, it could be that your sink is leaking from a drain gasket or seal which has eroded or come loose. The best way to check this is by filling the sink with water before allowing it to drain away.

  4. 4

    Unidentified issue. If you are still dealing with a leak that does not seem to be identifiable, it is time to call a plumber. They will be able to tell you where the leak is and what needs to be done to fix it.  

Next, it is time to fix the leak! Here are our top tips to fix a leak under the sink, with steps for each of the three main leak types we have discussed above.

For a pressurised water hose leak:

  1. 1

    Turn off the water. This leak is in the pipe which carries water to your tap, and so will continue to spray water for as long as the water is on!

  2. 2

    Tighten the fittings. The main cause of an under sink pipe leaking are the fittings around shut off valves, so it should be a simple fix by tightening these up. You need to use a wrench the hold the valve while tightening the compression nut with your hand.

  3. 3

    Still leaking? Tighten the faucet connection. If it is still leaking when you turn the water back on, it could be the connection between the pipe and faucet. Use adjustable pliers to tighten this up.

  4. 4

    If these two methods don’t work, call a plumber.

Found a leak in the drain line? It's likely caused by one of three things: a blocked drain, a loose connection or corrosion. Follow these steps to fix it:

  1. 1

    Tighten the connections. Use a wrench to make sure all the compression nuts and connections are fully tightened.

  2. 2

    Unblock the sink. After the connections have been tightened, ensure that you fully unblock the sink.

  3. 3

    Still leaking? It's likely caused by corrosion. This means that part of the pipework beneath your sink will need replacing.

  4. 4

    It’s time to call the plumber!  

If your sink is leaking from a drain gasket, these steps will help you fix it:

  1. 1

    Grab some plumber's putty. This is one of the easiest problems to fix as long as you have plumber's putty to hand.

  2. 2

    Unscrew the sink drain. Be sure you have some towels close to hand in case of any excess water in the drain.

  3. 3

    Clean out old putty. You may find that there is leftover which previously sealed the gasket.

  4. 4

    Add a fresh layer. Once the old putty is gone, add a new layer.

  5. 5

    Screw the drain back together.

  6. 6

    Alternatively, if you can’t get hold of plumber’s putty try silicone caulk.

  7. 7

    If these steps don’t fix the leak, call a plumber.

With this simple step-by-step guide, you now know how to stop a kitchen sink leaking, and when it is time to call in the professionals.

Now that you have sorted your leaking sink drain, why not check out our comprehensive guide for how to clean your sink and remove stains or our guide for how to clean stainless steel sinks?

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