On Tue, 10 Aug 2010 16:50:40 -0500, "The Post Quartermaster"
wrote:

I'm going to run a water line out to a little outbuilding I have out
near the barn. The line I am going to tap off of is probably a 3/4"
line. If I run a larger diameter, say a 1 or 11/4 inch from there to
the outbuilding would that result in any increase in pressure at the
outbuilding or would the fact that there was a 3/4" feed negate any
increase?

If the valve on the spigot or outlet you'l be using has a greater
diameter than the one on the 3/4" pipe, you'll have LESS pressure.
There is no way to get more in pounds per square inch than the 3/4
has.

Also the extra length of pipe lowers the pressure some, but not very
much, maybe not even noticeable. Using larger diameter pipe will make
the effect of that less, but maybe not noticeably.

How long will the pipe be and why do you need more pressure?