The evaporator system in a car is designed to recapture fuel vapors from the fuel delivery system, fuel tank, storage.
Most Evap codes I've ever seen were self-correcting. What I mean in that case is that once you reset the code most that I've dealt with go away. Check your fuel cap to make sure that it's installed properly and see about resetting the code. If he comes back, you will have to do some more digging.