Hey all, I am about to do the plumbing water system with a 20 gallon tank inside. From what I’ve read and viewed allowing air to be displaced when filling and draining is important. Thinking of a top hatch 6 inch in diameter to fill from ( easy in my design to access) which would allow for air displacement while filling. Because I have bench seats I am not thrilled at running water tubes in walls to get an elevated water overflow to displace air as it is draining. Thinking about a short 6 inch elevation within the bench with a check valve allowing air in but no water out. thoughts anyone? It would be nice to avoid one more hole in the floor as they are typically done and I kind of love check valves.
While that should work, I’d also want a drain for the tank.
You do not just want you 100% need to have a drain in your water tank.
Tanks get nasty over time especially after hot weather. You need to dump all water and do it multiple times during tank sanitizing procedure. Unless you like water smelling like stale pond and swarming with creatures
Also you need to dump water as part of tank winterizing to avoid damage from freezing. Even if tank is not full freezing expansion can damage it.
There also situations where you end up getting bad water filled and need to dump it all.