I am currently doing a job in a shop for a customer. It was previously a hairdressers. The shop has 2 flats above it and a lane which runs beside it to other premises. I stripped all plumbing out the main shop so only a new toilet remains through the back. The 22mm main comes in this toilet feeds the shop and then goes upstairs. Behind the toilet is a store room which was the old toilet. I re piped the back of the shop. Put a new stopcock in for the shop and a new one for the 2 flats above. In the old toilet i stripped everything out, When stripping out took away a pipe that went through the outside wall which i presumed was for an outside tap. Outside the back of the shop has been used to dump all the building waste so i couldn't get near the other side of the wall to check. I got a call today saying that the building on the other side of the lane ( a physiotherapist) has no water and its our fault. Am i wrong in thinking every separate building needs its own mains supply. The pipe in question was 15mm hep. Anyone came across this before?