Look at the bottom of the pipe and see if there ios evidence of scraping on the pavement. If not there shouldn't be a problem. On my prior class c I had 2 dumps. The one for the coach grey and black was inside a storage compartment. The one for the outside kitchen (separate 12 gallon grey tank) hung below the body of the coach and was about 3 or 4 inches off the ground. I never had an issue with rubbing anything.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054