[Shop-talk] a(nother) plumbing question

[Randall]

> I capped off all the openings and used a pressure 
> gauge on one pipe. To my surprise the pressure was about 75 psi! I 
> turned on a nearby faucet and the pressure dropped to 30 psi. 
> It turns 
> out that the previous owner used 3/4" pipe to connect the 
> house to the 
> meter, a distance of 700'.

IMO, if the flow of a single faucet dropped the pressure by 45 psi, you have
something else going on besides 700' of 3/4" pipe.  This chart says even 4.8
gpm (which is a big faucet) should only drop about 17.5 psi through 700' of
3/4" steel pipe.
http://www.engineeringtoolbox.com/pressure-loss-steel-pipes-d_307.html

Randall