Directionality is important.
Especially in important daily flows, like home plumbing.
Here’s an example of a really routine flow, represented in one of our favorite methods.
What happens when you reverse the directionality (because City Sewer Cleaners vacuumed the sewers so vigorously that they forced tons of sewage into your tiny house’s tiny pipes)?
Oh my. I’ll leave that up to your imagination. Luckily there is a built in mechanism to save your stuff.
…if not your yard. Or your neighbors’.
As Bill sez, waste is just energy that lands in the wrong place at the wrong time!
(inside my house)
In conclusion, creating a smaller closed loop for the water/plumbing system might make it more manageable instead of creating a horrifying monster to deal with on a comparably tiny scale.