We have 3 bar coming into our house and when loo is flushed or shower run, all other outlets drop their water pressure. We are looking to make a granny flat on the property for my mum, but as we will be tapping off the same supply after the meter, I am worried about loss of water pressure in the main house or vice versa. Do I need to get a plumber to fit some type of pump? I have no idea. I hope I have explained myself properly and that any plumber might help. Thanking all in advance.