We are new to motorhoming and need to hear from the experts! We have had a pull behind for years. So my question....When we dump the smell is horrible inside the coach. I dont know if we are doin...
I'd check the ball valve seal on the toilet first thing. Second, sometimes the bathroom sink is plumbed to the black tank... and it usually has an air admittance valve. That is likely shot, so replace it, or if one is a plumber, replace the trap with a HepVo waterless trap, which not just keeps smells from coming out, it allows air to come in the drain to equalize pressure.