I now concluded that my cold taps are mains fed have high pressure downstairs and really low pressure upstairs to the point if i flush toilet or sink cold tap on the shower or bath tap top working and vice versa cant understand how it can be spot on downstairs and rubbish upstairs

steve, July 2009

I agree with above or the tap heads themselves could be gunged up unlikely but worth picking one as a sample and cleaning out tap head, other than that the pipe supplying upstairs is too small has to be it should be 3/4" reduced to 1/2" into tap. another way of looking at it is to connect a hose to kitchen cold bring other end of it up to basin upstairs and run ie. compare pressure in basin between hose and tap. if different, i suggest you attach the hose to a problem tap and flush it out then open remaining faulty taps again comparing pressure

ciaran, July 2009

Simply - there is a restrictor or isolator valve in the cold feed to upstairs...or a blockage, maybe.

John, July 2009