Is it leaking where the tailpiece meets the shank? Or do you have a elbow shank?
I would think that regardless of what you're missing, an O-ring should be available to seal the leak. Home Depot should be a fine source. There are lots of random faucet (sink) gaskets and seals you can probably pick up to solve the problem.
Take your faucet in with you to find the right one.
Make beer, not bombs.
(...and not bottle bombs either.)
Primary Fermentor - *empty*
Primary Fermentor -
Secondary - Mystery IPA
Bottle Conditioning -
Keg Conditioning -
Draft: - Apfelwein, Belgian-style Dubbel w/ Grains of Paradise
Bottles:(and still in stock): FIRST AG - (I)IPA 4.1.07, PK's Warm Spring Marzen, Summer Cerveza -BANG, PK's Winter Spice II, Espresso Stout, Indiana Pale Ale, PK's Chocolate Bitter II, Porterfield Porter, and New Year's 2006 remnants.