how do i replace washer in outside tap?

Turn the mains water OFF, then undo the large hexagon nut that holds the tap insert onto the tap body. Ignore the smaller hexagon beneath the turning handle. With the tap body out, you'll see the washer, and the new one will either be a push fit over the stem, or it could be held with a small brass nut. Reassemble with the tap turned open, and job done.

John
June 2009