I have an outlet pipe that has been leaking for about three months just dripping intermitnently and some time stopping, I don't know where it is coming from we have checked all the obvious places,we have just noticed that recently our hot water taps are losing pressure and if you turn one on or the washer the others won't work. It is taking nearly an hour to run a bath, I don't know if they are connected. Any ideas

I have an outlet pipe that has been leaking If by "outlet pipe" you mean drain line the two problems aren't connected.
How old is your house and what material are the pipes? Copper, plastic or galvanize? Did this pressure loss just happen or has it been coming on for some time? Do you flush your water heater on a regular maintenance schedule? Back to you, Tom