That we should be working much harder to pick ourselves out of the gravity well and find another home elsewhere because this one's not in good shape and getting worse.THAT'S WHAT THE SCIENCE SUPPORTS.

As it was explained to me, the system depends on gravity and if the rise to the shower is not sufficient, gravity does not have enough runway to get the job done.   

The strangest story is that 4 days after closing on one of the homes the neighbors told me that a 14 year old boy had stabbed his grandma to death and stuffed her into a gravity fed furnace in the home, he was later killed by another family memberWell, when the new tenant moved in she had been there a week and I was chattting with her about how every thing was going, and she said "Well great but the house is haunted".

Either will spray water inside shower wall were gravity will then rTake it wherever is lower.

Andrew,A 100 year old house has likely settled unevenly as gravity takes over. 

The earth moves around the sun to counterbalance the sun's gravity pulling the earth into it.

I also have to replace the existing gravity furnace and have the ductwork removed so that I can have space to finish off the basement. 

Whoever you are dealing with probably does not comprehend the gravity of the screwup. 

Using very simple concepts, Newton was able to put together laws for how time, gravity, mass, energy, momentum, etc all played together nicely.

RV tanks rely on gravity (in my experience)  perhaps you could let the tanks run into some sort of aproved tank that is larger and could be emptied less often, thus reducing expense.