I have noticed that the 15mm mains feed to my cold water tank is pretty damn
noisy when the tank is filling up.
The mains run is quite long from the basement up to the loft where the CW
tank is & has a fair few bends in it on its way to the loft.
I`m wondering however if its actually the filling valve to the CW tank which
is actually the noisy part (cheepest, ****test valve installed by a plumber
I had round once). The tank is fully lagged in the loft & I can still hear
it !
If I replaced the valve on the tank would this stop the 'rushing' noise in
the pipes? Ideally I want something that isn`t going to restrict the flow as
the tank will need to fill quickly when the power shower is on for instance.

Steve