Thinking that a leaking tap is nothing to worry about is the wrong attitude to have. A simple problem can lead to long-term damage. Not only can it cause major damage, it will increase your water bill significantly. You can actually loose up to 2000 litres of water per year from one leaking tap. If you are not confident that you can fix it by yourself, you should seek professional help.
Firstly, you need to turn off the water supply. You can usually find the mains tap in the front of your house. If you live in an apartment, it will normally be in the laundry or bathroom.
Turn on the leaking tap to let out any water that is still in the pipe, then leave it on. Put the plug into the basin so that no small parts can fall down the drain.
Remove the tap handle. The screw for the cover can normally be found under the cold or hot symbols. Once the cover has been removed, you will be able to see if you need ceramic disks or rubber washers. If the tap handle rotates more than a quarter or half a turn, it is usually a rubber washer, less than this and it is usually a ceramic disc.
Now you need to remove the flange. It could either be screwed on or held in place by a spring.
You should now see the tap bonnet and spindle. Use a shifter/spanner to take off the bonnet and tap. You will now see the headgear and a large red washer, o-ring, and jumper. The jumper valve needs to be removed.
Worn o-rings are a common reason that kitchen taps end up leaking. Check to see if the seals and o-rings are worn, as they may need replacing.
Remove the spindle by screwing it all the way down until it falls out. Remove all other parts and clean the tap bonnet with a clean cloth and wire brush. Once cleaned, replace the Body Washer, O-Ring and Tap Valve. Do not forget to lubricate all three parts with waterproof lubricant.
Once that is done, refit the spindle and bonnet, making sure that it is not too tight.
Once these five steps are completed, you need to reverse the entire process in order to put it all back together again. Screw the tap bonnet back in and apply some silicone on the body before applying silicone to the flange. Put the handle back on and then the cover.
Leave the tap in an off position before turning the mains back on. Once the mains have been turned back on, you need to check that there is no longer a leak.
If this procedure is followed correctly, your tap should no longer leak and you are on your way to saving precious water. If you still have problems after following these steps, seek professional help.