A dripping kitchen tap is one of the most common plumbing problems in the home.
The good news is that you don't need to replace the whole tap. In many cases, the problem can be fixed by replacing the tap valve, also called cartridge or ceramic valve.
Replacing one is usually a straightforward DIY job and can often be done with a few basic tools.
First, check what type of kitchen tap you have
Before trying to work out whether you need a hot or cold valve, look at your kitchen tap.
If your tap has separate hot and cold handles, each side has its own valve inside. This is the type of tap covered in the steps below.
If your kitchen tap has one single handle that controls both the hot and cold water, it works differently. These taps have just one cartridge inside the tap, which controls both the water flow and temperature.
So, with a single lever tap, you don't need to work out whether the hot or cold valve is faulty. If the tap is dripping or the handle isn't working properly, the cartridge is usually the part that needs replacing.
If you have separate hot and cold handles, read on to find out which valve needs replacing.
How can I tell if it's the hot or cold valve?
If your kitchen tap has separate hot and cold handles, each side has its own valve inside.
It can be difficult to tell which one is causing a drip. You might think you can simply feel the water coming from the tap. If it's hot, you need the hot valve; if it's cold, you need the cold valve.
Unfortunately, it isn't always that simple. Water can stay inside the tap or mix together inside it before coming out of the spout. This means the temperature of the dripping water isn't always a reliable way to tell which valve is faulty.
The easiest thing to do is test each side separately.
Step 1: Test the hot side
First, make sure the tap is turned off. Turn on the hot handle and let the water run for a few seconds. Now turn the hot handle off fully.
Watch the end of the tap. Does it continue to drip?
Pay attention to whether the drip gets worse, gets better or stops after you've used the hot side.
If operating the hot side clearly affects the dripping, the hot valve could be the one that needs replacing.
Try it a couple of times so you're sure.
Step 2: Test the cold side
Now do exactly the same thing with the cold handle. Turn the cold water on for a few seconds, then turn it off fully.
Watch the tap again. Does the dripping change?
If the drip gets worse, gets better or stops after using the cold side, the cold valve could be the problem.
By testing the two sides separately, you can often work out which valve is causing the problem without taking the tap apart.
Still not sure? Try this
If you are still unsure whether it is the hot or cold side, you can try turning off the water supply to each side separately.
Depending on how your kitchen is plumbed, you may have a small valve on the hot and cold water pipes underneath the sink. These are called isolation valves and allow you to turn off the water to the tap without turning off the water to the whole house.
If you have these valves, turn off one side at a time and test the tap. This can help confirm whether the hot or cold side is causing the problem.
Turn off the hot water
Turn off the valve supplying the hot side of the tap. Then try the tap.
If no water comes from the hot side, you've successfully turned off that supply.
You can then check the cold side separately.
Turn off the cold water
Turn the hot supply back on and turn off the cold supply. Test the tap again.
This can help you work out which side is causing the problem.
What if the tap is leaking around the handle?
If water is leaking from around the handle of your kitchen tap, then usually the valve needs replacing.
The valve sits underneath the handle and controls the water flow. When the valve starts to wear or the seal inside it fails, water can escape around the handle instead of staying inside the tap.
To work out whether it is the hot or cold valve, check which handle the water is leaking from.
- Water leaking around the hot handle → replace the hot valve.
- Water leaking around the cold handle → replace the cold valve.
- Water leaking around both handles → both valves may need replacing.
If one handle is also stiff, loose or difficult to turn, this is another sign that the valve on that side needs replacing.
What if I still can't tell which one is faulty?
Don't worry, sometimes it isn't obvious.
If you have tested the hot and cold sides and still can't work out which one is causing the drip, buying both valves can be the simplest option.
If the two valves are the same age, there is a good chance they have had a similar amount of use.
Replacing both at the same time also means you won't have to take the tap apart again if the other valve starts dripping a few weeks or months later.