Usually the higher sewer pipe is for access for cleaning/clearing, sometimes at an elbow, sometimes not.
The site next to ours at the resort has an odd sewer opening location that is on higher ground than their RV. They consistantly have issues with it, and so do we when the wind is blowing our way. Good thing they arent there much.
When the line gets clogged it usually ends up spilling out of their rigid line connections, which makes a mess. I just can't figure the logic of having sewer acces higher than the RV.
Some use macerators(?) but they are even limited to some extent.
At one Camp Ground the water pressure was so high, it was blowing hoses off the crimped connectors. Never seen that before. Plus the water was nearly 40ft away.
My Other House Is A '02 Jayco 31FKS Designer TT