Holding Tank Terminations
A coworker recently purchased a 2021 Prowler 271BR. He's telling me that his Black Tank valve must be open for him to be able to empty his Gray Tank. This does not seem correct to me. Is this SOP for ...
Forum Discussion
StarkNaked wrote:
There is nothing stopping someone from putting the plumbing together like this.
But... If the black tank is full, and the gray tank is empty, and the gray tank valve is opened, it means that the black water would back flow into the gray tank until they are both at the same level. So, half of the black water would be in the gray tank. Doesn't sound like a good thing!
Actually the reverse could be handy.
If taking showers, it's not uncommon for the gray to fill up first. By opening the gray valve, the excess gray would flow to the black tank giving you more space for showers.
Even if the black tank back flowed into the gray...not really a big issue.
- Most people don't drain them separately, so it's all going to the same place.
- Gray water tank can get pretty nasty and smell bad...of course, if the P-traps are working, that's largely irrelevant.
- I don't want to stand in the water from either tank if it backs up into the shower.
- About the worst, I could see happening would be if a chunk of poo lodged in the smaller gray water pipe but given that it would be gravity flow with negligible head, that's unlikely.
