Hi All, Please excuse this basic question I know NOTHING about plumbing. I work in a new community centre which has been finished by builders who were going bust and therefore took shortcuts all over the place. My building therefore has many defects. At the moment we have a blocked loo. When I push a plunger down it dirty water comes up out of the sinks. Is it standard to have the sink and sewage pipes joined up? Maybe i'm being naive but I thought they'd be seperate!?!? If this is standard I'll get on and get it rodded. If not the council will have to sort it out. Please help!