Excuse my terminology in explaining my problem as I am not even an amateur plumber. Our pipes scream every so often. This morning it has happened five times. When I say scream, it is not a knocking, it is a long high pitched hum, which can sometimes last a minute or longer. I imagine the pipes are vibrating. I noticed this morning it happened when our hot water was due to come on (we have an old tank system, probably installed c.1983). But sometimes the sound starts when nothing is on, taps, heating, HW, washing machine etc. I used to run the bathroom sink and kitchen cold water taps and the noise would stop. Now, that doesn't seem to help. The pressure on our boiler is high, around 2.0. I have bled the radiators to get it down, but it rises again slowly. I'm not sure how to relieve the pressure by other means. I have had a look at the water tank and the water feed (valve?) looks corroded, build up of minerals on it. I am at my wit's end. It woke me up this morning. We live in a one floor tenement flat in Edinburgh, and I'm sure it is affecting the flats below is and next door (noise nuisance I mean). The noise is hard to locate. You can hear it all around the flat, not just near the water tank or stop cock, but it is louder near the main water inlet pipe near the stop cock. I have adjusted our stop cock so that it isn't open very much in the hope the pressure will be relieved but again, this doesn't seem to have helped. Does this sound like a big job? Obviously I'm not going to attempt to fix it myself. Is it something I can fix easily, or have I exhausted possibilities? I don't think we have air chambers on the pipes as it is an old system. For some reason it has been happening more often, perhaps as we've had the CH on? Any advice would be appreciated. My husband refuses to call out a plumber!