"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Lobster wrote:

Anyway, I'm now considering biting the bullet and installing a
'proper' blue MDPE pipe, which means digging up the drive and
considerable expense/hassle, and so not something to be undertaken
lightly, and unless I'm 100% sure it's going to make a decent
difference to the water flow at the two shower heads. So my question
is, is there a way of finding out? How can I be certain that the
bottle-neck is caused by the length of water pipe under the drive,
or elsewhere (eg the yards of 15mm pipework inside the house, or
whether the water pressure out in the road is not that great in the
first place?)

You could install a pressure gauge close to your rising main, and measure
the static pressure with no appliances running. This would be the same as
the pressure out in the street. Then turn on all your taps, and measure it
again. The difference in pressure would represent the pressure drop along
your underground pipe.

Thanks for that. I'll need to equip myself with a gauge first; I guess once
I've made some measurements I'll be back here with the numbers asking what
the implications of the results are!

As a follow-up to this... the easiest way to attach a gauge close to the
rising main would clearly be via a hose to the drain cock adjacent to the
stop cock. Or would the innards of the valve contribute too much to any
pressure loss? Also, can anyone tell me what sort of flexible piping
you're meant to attach to these drain cocks? I've often wondered in the
past, while experiment unsuccessfully with lengths of garden hose, which are
just too large and even with jubilee clips fitted, they leak badly.

Thanks
David