Hi all

I posted a query here a few months ago asking whether it was likely to
be worth my while biting the bullet and replacing the old incoming water
main with a modern wide-bore MDPE affair, specifically to prevent my
shower pressure from being so badly affected by other water outlets in
the house (it's all fully mains pressure, with an unvented HW system).
I was advised that the best course of action was to take some water
pressure measurements close to the stopcock, which should help diagnose
the location of the pressure drop (see original thread below

http://tinyurl.com/65xgo

Finally(!), I've got around to buying a gauge, and have put it to use.
There's a threaded outside tap very close to the stopcock, so I was able
to attach the gauge there.

Here's some data:

a) Static pressure, no water flowing: 3.9 bar
(Flow rate measured at kitchen sink, no other water running: 20 L/min)

b) Shower running (nothing else): 3.8 bar

c) Shower running, plus bathroom sink tap and toilet flushing - causes
severe reduction in shower flow rate: 2.7 bar

d) Every tap/shower in the house running - causes shower to stop
completely: 1.8 bar

All pressures measure at the outside tap.

Now, I'm still not clear whether this helps. Presumably, if the
pressure had stayed at 3.9 bar under all 4 test conditions, that would
have told me that my incoming pressure was OK, and that the restriction
was inside the house, right? But these results would seem to be
intermediate, so I'm not sure how much benefit there would be if I went
ahead and had the new MDPE pipe fitted?

Any thoughts, or any other diagnostic measurements I should make? :-)

Thanks
David