I'm moving my washer in the laundry room, but I have a question about drainage. We're on a septic system here, and the current washer drains into a french drain system and is carried 200 plus feet from the house out into a field. (Apparently, this is up to code in Alabama.) My question is...When I run my new drain line to be tied into the french drain system out back, do I have to install a p-trap before connecting the drain line to the french drain, or am I safe to let it just gravity drain since there's no gas coming back in?