On Wed, 21 Dec 2005 16:29:04 -0600, j probose
wrote:

I am planning the installation of a waste pipe (either 3" or 4") over a
distance of 46 feet. The drop in elevation over that distance is 30",
which I calculate to be aprx .65 inches per foot (instead of the nominal
.25 inches per foot). Is .65 inches per foot too much? I COULD
excavate more at the high end, and come closer to the .25 inche per
foot, but is it worth the extra effort? Also, does the pipe size make a
difference?


Yes, that's too much. You should go for between 1/8" and 1/2" per
foot, trying for as close to 1/4" per foot as you can get.