Bob Wheatley wrote:
snip
There are two different characteristics that affect the perceived amount of
water flow from a faucet.
1. Pressure
2. Volume

Plumbers don't use those terms interchangeably. Upsizing your lines will not
increase your pressure. It will increase your volume.....BUT.....
ONLY if you change the valve to something that was designed to accept the
larger supply lines.

Increased volume {like able to fill the bathtub up quicker, for
example, is this right?} is one thing I definitely want out of all
this. But since I've come to understand (after reading Paul's
excellent post) that I can't get any *significant* pressure increase as
a result of upsizing my lines, I couldn't help but anticipate what
you're saying here about the valve having to be one that 's designed to
accept the larger supply lines for these larger supply lines to be able
to deliver on that.

The industry standard (in the states) is 1/2". It works
just fine on every valve I've installed for thirty years. I thought I read
in one of the previous posts where someone brought up your valve. That's the
key.
If you've tried changing showerheads and/or removing water savers then I'd
recommend that you go out and buy yourself a brand new Moen pressure
balancing valve and install it.

I thought someone else suggested adjusting your PRV (pressure reducing
valve)
I have no idea if you have one or not,


Just the one that reduces/regulates the pressure for the entire
household.


but if you don't have a history of
problems and now you do, I'd look real hard at that valve if you have one.
The "moving parts" of any system are always the weak link.
Pipe is not a "moving part".
If this problem just popped up, look at the "moving parts" first.

Bob Wheatley


Thanks for this helpful info, Bob.

Ken