[Bill Douglas]

Years ago I had a similar thing. The galvanised pipe from the toby (that's what we call the mains tap out on the footpath) had got rusty. I was surprised any water got through when I saw how rusty it was. I replaced it with 25 mm PVC - U pipe. It's been great ever since. Two showers running at the same time and taps used without screams from the bathroom.

If your pipes are OK and you have a pressure limiting valve (stops surges that may blow up your pipes) the filter in it may be blocked with mud and crud.