Belly in sewer pipe(Basement )
My sewer pipes were not properly hung @ a productive enough slant to ensure bellies don't occur and proper flow to the outside of the home. So now they must be re-hung. Its about 20 ft of pipe to the outside spot. My question is ," what is the viable angle to hang them?" And," how often should a hanger be installed?" Some say every 4ft. The improper hanging is causing water to backflow up out of my downstairs bthrm flooding my kitchen & bathrm on the 1st floor. All the water, whether it's the upstairs toilets, sinks,dishwasher, showers, or washing machine, they're all flowing back out of that bthrm toilet.