Replacing a tap washer is not a difficult process. Although if you are not confident with your DIY skills then it will pay to let a professional carry out the work for you. Eltham Plumbers are a professional service and deal with plumbing issues.The first thing to do is to isolate the water supply to the tap. Once you have done this you should leave the tap fully open to drain. Some taps have a non-rising spindle with easy clean an shrouded cover which needs to be removed. This is held on by a fixing screw under the coloured cap (for either hot or cold). Remove the cap by flipping the cover off with a small screwdriver. Underneath this cap is a screw that holds the cover to the tap, remove this screw and the cover ,exposing the tap body. Using a spanner remove the head of the tap from its body. Once the head is off, you should see the washer at the base. Visually check the seat and body for debris or anything that may impede its operation as you do not want to go through this process again if anything is present. Simply remove the old and fit the new washer, which may or may not be secured with a small nut, if it is, then care must be taken not to shear this nut if it is hard to undo (use penetrating oil and measured effort) as you will have to replace the whole tap if it is damaged. With the new washer in place, reassemble the tap in reverse order. Once you are happy that the tap is restored, the water supply needs to be restored. The tap should then be operated through its fully open and closed positions to ensure that there is no leaking. Job done. An Eltham Plumber can change washers.