Tools and materials
The tools and materials you need to change a washer are available from your local hardware or plumbing store. You will need: an adjustable spanner to fit the tap nut valve, an O-ring Silicon lubricant or Vaseline Needle nose pliers
1. Turn off the mains: this will stop all water flowing into your house or office. The tap & water meter for homes will be out on the street or in your front yard next to the street. If you live in a flat or apartment the mains tap will probably be inside, for example in the bathroom or a cupboard. Turn on a tap in or around the house to make sure that the water has stopped running. (If the water has not stopped running, it will be wise to call a professional plumber). If the mains tap has not been used for many years, you may need a pair of pliers to help turn it off. Ensure you know where the mains tap is to be able to turn the water off in an emergency. If you are not sure where it is, even if you don’t need to change a washer, find out now!
2. Undo the head nut: once the mains has been turned off, undo the head nut on the leaking tap.
3. Replace the washers: you could just replace the tap washer, but it is a good idea to replace all three washer. These are: The large washer around the top of the nut, which is called the body washer (usually orange or green in colour). It should lift off easily. The O-ring on the spindle. To change the O-ring, you need to fully close the tap until the O-ring appears. Then, with a pair of pliers cut it off. The new O-ring should easily stretch and roll on to the spindle.
Lastly, replace the tap washer. It may simply slide out of the spindle or stay sitting in the centre of the tap, in which case you will need a pair of small pliers to remove the washer.
4. Reassemble: first ensure the spindle and the threaded areas are lubricated with a silicon lubricant or Vaseline.
5. Turn the mains back on: once the tap is reassembled, open it three quarter way and then turn on the water mains. When turning the tap off after the washer has been replaced, use gentle hsnd pressure. Over-tightening will cause a lot of damage to the tap seat. A tap should only be tightened until the water flow has stopped, no further. Note: If the tap is still leaking after you have replaced the washer, it means the seat is “pitted” and you will need a professional plumber to regrind the seat for you.
Most of inside taps use12mm (1/2″) washers; while outside taps (garden taps) take 3/4″ (18mm). Washers cost around $2.50 to $3.00 each. The most popular washer (used by most plumbers) is a heavy-duty washer suitable for taps, with a copper base and a yellow top (Delaware valve) – approximately $3.50 each. This same type of washer is good for outside garden taps – 18mm costs approximately $3.00 each.
If your taps are very old, take the worn-out washer to the hardware or your local supply store so that you get the right washer for your tap.