You should not need to run water in all of the traps everyday to prevent them from drying out .... that is nonsense. The job of the vents is to prevent the traps from siphoning dry. If the traps are actually dry, it could indicate a problem with venting. There may be other possible causes of the smell as well. You should not have to figure out the problem yourself. I would go directly to the builder / whoever you bought the house from / whoever is responsible for the home warranty and indicate that the plumber has failed to resolve the problem. Be persistent and direct. Indicate that if he is not able to resolve the problem promptly, you will call in an independent professional to diagnose the problem, and pursue compensation in small claims court.