The first thing to do when renewing the washers of water taps is to shut off the service pipe leading to the tap. If the pipe is from a house cistern, then the stop-cock must be closed. If there is no stop-cock, the hole in the cistern must be plugged with the pointed end of a broom-handle. If the cock to be repaired communicates directly with the main, then the main cock in the cellar, if there is one, must be closed, or the water company's cock in the pavement. Having cut off the water from the main, unscrew the upper part, the middle stem, of the cock with a spanner. Sometimes a small ordinary screw will be found in the edge of the shoulder part; this must be unscrewed with a screwdriver and removed first. When the stem portion of the tap has been removed, the small part that has the worn-out washer on it will either come away with, or will be found loose in, the body of the cock, and can be lifted out with the fingers. This part is frequently called the "jumper," and to this the washer is secured by a small screw collar, which is easily removed with a screwdriver. When the old washer is removed and the new one is slipped on, this screw collar is replaced; it merely holds the washer on. The jumper and other parts are then replaced in their order.

Washers of red rubber are more lasting than ordinary-white or gray washers.