Looking at a manual from a 94, I'd guess its off the evap control valve. There's a line that goes to the evap canister from the fuel tank. Another line from the evap canister goes to a vaccum line that is tee'd into to evap control valves.
Your best bet is downloading the 94 manual from here if you don't want to go buy a repair manual:
Honda / Acura Manuals - Hondahookup.com
Its almost impossible to explain without seeing the diagram. Its really not a big deal to take care of though. The worst it will do is affect fuel economy.