Hi I’m after some advise I have a property and there is a inspection cover where various pipes go into and then into the feed which goes to the street , there is one toilet goes into here and bath room and toilet so a few feeds into the inspection cover the problem is where it goes out to waste and when the bath is let out it seems to build up in inspection cover ? I put my arm into where all the water exits this doesn’t seem to be a straight pipe it seems stepped a bit like a pee trap but I could think this on a waste to road pipe shouldn’t it be a straight pipe any help appreciated also it’s a clay pipe