Please help! this is driving my wife and I nuts. We've just moved into a house with a small downstairs toilet. At night for some reason the cistern in the toilet starts screaming. The mains water pressure tap is in this toilet too, if i turn that down it stops. But then we have no pressure in the sinks and the shower so i have to turn it back up again in the morning. It's a small enclosed cistern. Can I stop this and still keep good pressure to the rest of the house?

What the thescruff says... change the valve in the cistern.

If it still makes a racket and the cause is definitly very high pressure then you can get a pressure reducer fitted in the supply to the toilet only.