Pillar taps
To rewasher the conventional pillar tap, you must cut off the water supply to the tap. If the fault is in the cold water tap over the kitchen sink (which should be supplied direct from the mains) you will need to turn off the main stopcock. Other taps may have a stopcock or gate valve on the distribution pipe serving them; if so, turn off this valve. If there is no such valve, tie up the arm of the ball valve serving the main cold water storage cistern and open all bathroom taps and the kitchen hot tap to drain the cistern and distribution pipes. Unscrew the protective cover of the tap. You should be able to do this by hand, but if not you can use a pipe wrench, although you must pad the jaws to avoid damaging the chromium plating on the tap.
Insert an adjustable spanner under the base of the cover, unscrew the headgear nut and remove the headgear. The jumper (or valve) of the cold water tap over the kitchen sink will usually be resting on the valve seating in the body of the tap. Remove it, unscrew the small retaining nut and replace the washer. If the nut proves difficult to unscrew you can replace the jumper and washer complete. Some taps may have the jumper pegged into the headgear. Although it will turn, it may not be easy to remove. You may have to unscrew the retaining nut with the help of a little penetrating oil. If the retaining nut will not move, insert the blade of a screwdriver between the plate of the jumper and the base of the headgear and break the pegging. Replace the jumper and washer complete, but burr the stem of the jumper with a coarse file to ensure a tight fit. Reassemble the tap and turn on water.
Shrouded-head taps
To expose the inside of a shrouded-head tap, remove the head. This is normally done by prising off the plastic ‘hot’ or ‘cold’ label, under which there is a retaining screw. Undo the screw and lift off the shrouded-head. A few shrouded-head taps have the head retained by a tiny grub screw in the side, similar to the grub screw retaining the capstan or crutch head of a conventional tap. Others may have no retaining screw at all, in which case after they are fully opened you must give a final turn that allows the head to be pulled off.
Supataps
Rewashering a Supatap is a quick job that avoids cutting off the water supply. Open the tap slightly and with a spanner unscrew and release the retaining nut at the top of the nozzle. Start turning the tap; there will be an increasing flow of water, but this will cease as the check valve falls into position. The nozzle will then come off in your hand. Tap the nozzle on a hard surface (not one that will chip) to loosen the anti-splash device in which the washer and jumper are fixed. Turn the nozzle upside down and the anti-splash will drop out. Remove the washer and jumper by inserting a blade between the plate and the anti-splash and insert a new set. Replace the antisplash in the nozzle and reassemble the tap, remembering the nozzle screws back on with a left-hand thread.