What
happens to water pressure in a pipe as it goes up and down in elevation while
crossing the terrain? __Elevation Change__
illustrates these examples of the effect of elevation on water pressure. 11`

Given a water source at
80 psi, what is the pressure in a pipe downhill 50 feet lower than the source? Click on the __Elevation Change diagram__ and adjust the window so you can read this text.

The water is
initially at 80 psi and a 50-foot column of water is added under it. At the
lower point, the static pressure is 80 psi plus 50 x 0.433 or 80 + 21.7 or 101.7
psi pressure.

Reversing the example, place the source 50 feet lower than the
demand point.

In this case, the 50-foot column of water is acting downward against
the source. At the point of demand, the static pressure is 80 psi minus 21.7
psi or 58.3 psi. The weight of water in the pipe works with or against the source
pressure.