I had a contractor add an additional bath. When we were planning out the project, he mentioned my lack of a water heater valve drain pan. Instead, he installed a drain directly into the septic line that runs from the new bathroom (toilet/sinks/tub) out to my main septic line. Is this actually safe? There’s no trap as far as I’m aware. Anytime the bathroom is used, there’s a significant smell. It isn’t rotten eggs, but it’s still concerning
There may be a trap but if no water was put in it won't stop the smells. Contractors sometimes forget to add water to floor drains. The water will also eventually evaporate from the trap if there is no regular source of water flowing down the drain. Add water to drain and see if smell goes away.
NO NO NO. It's not safe. Your plumber was completely incompetent or negligent to do that. It definitely needs a trap. I would make him fix it.
A water heater drain should never drain to a septic tank.
One purpose of the drain is to reduce or eliminate water damage to your home in case the tank leaks. However, if the tank develops a fast leak and your septic tank absorbs it, if unnoticed for just a few hours, your septic field could be irreparably damaged.
A water heater drain should be installed like a sump pump / foundation drain -- it should direct the water outside onto the ground or to a municipal storm drain. It should not go to a sewer or septic system.
