If a tap continues to drip after it is turned off, it needs a new washer. If it leaks around the handle when it is turned on, the fault is in the gland around the spindle (the parts of a tap are shown, right). If you have to open a tap to replace the washer, turn off the supply of water. This can often be done at the nearest stop tap, but it depends on where the water is coming from (mains or storage tanks). If in doubt, consult your plumber. The gland can usually be repaired without turning the water off. There are only two sizes of tap washer in general use: 13 mm (½ in) for wash basins and sinks, or 20 mm (¾ in) for baths. Older washers were made of leather for cold water taps and fibre for hot water taps, but newer washers are plastic and these are to be used for both systems.
To get at the inside of a tap, remove the handle. If you have a cross type, undo a small screw in its side and lift it off. If it is a deep knob, poke out the little plug at its centre and undo the screw under it so the knob can be lifted off. If there is a shield below the knob, you will find it is screwed on and is often only hand tight. Grip it through a piece of cloth and take it off. Some shields have flats on them to unscrew with a spanner.
The gland nut is the upper part with six flats designed to take a spanner. Use an adjustable spanner rather than pliers, which might damage the brass nut. Tighten the gland nut (turn clockwise when viewed from above). Put the handle temporarily back on the spindle and try running the tap to see if there is still a leak. If the nut will not tighten more, yet there is still a leak, more packing is needed around the gland. Unscrew the gland nut and remove it. String will be found under it and around the spindle. Use a few turns of ordinary soft string, but saturate it with grease first — petroleum jelly will do. Replace and adjust the gland nut.
If the tap drips and a new washer has to be fitted, unscrew at the lower hexagonal part so the top of the tap comes away. The washer is on a metal jumper and is usually held with a small nut.
Remove the jumper, hold the metal part with pliers and undo the small nut with a spanner. Make sure any particles of the old washer are cleaned away before fitting a new one. Re-assemble and try the tap.