-For this call Homeowner had concern of toilet in second floor not flushing properly as well as other fixtures draining slowly. Upon inspection I found that the basement shower was draining very slowly with basement toilet operating normally. When flushing toilet on second floor a burst of air came out of toilet and on second flush no water drained down. There was a section of Sheetrock that had been opened beneath main drain line coming from toilet, I found that the drain line was level if not back-pitched toward toilet being the probable cause for toilet clog. After further inspection I found that the main vent for the sewer system was coming through roof on high side of toilet line. With the toilet line clogged there would be no new air introduction into drainage system causing trouble for other fixtures. I used inspection camera to confirm locations for drain and fittings. I recommended that the drain be cleared by a drain cleaning company in preparation for replacement of drainage