I have a severe leak under lthe grey cap of lmy antisiphon hose bib. Can this be fixed, or do I have to replace the whole hose bib?

Are you talking about the air gap of a dishwasher, the one on the sink counter? If so pull of the cap and remove the agp. There are two hoese of different sizes, check the connections for leaks and retighten. You can replace just this piece for about $15 or less, they can be prone to leaks but further discussion may reopen WWIII.

I have a different take on this question. Sounds like a outside hose bib's leaking from around the stem when the water's running. Who's right? Cheers, tom

The leak is not around the stem; it's the antisiphon device that is leaking, and I have since fixed it by replalcing a washer that sits .in that device