How Much Pitch or "drop" should residential sewer line have to insure proper 'flow' of waste to my septic system. I have new construction and am putting sewer line in (before I pour the basement floor concrete) and I need "inches per foot of line run" information.
Does the pitch drop change once I am outside the footings and on the way out to the septic tank? My septic tank will be approximately 100 feet out from the house and I am on a gradual slope site. I can easily place any depth on the tank and the drain field (proposed) is not within 500 feet of any property line. I am in Stevens County, Washington State and not within the city limits of any incorporated town (I'm WAY OUT).
Thanks for the Help. Dave:)

Id Say Ask Speedball On The Plummbing Section, My Guess Is 1" Per Ft
Ask Speedball.

We had to run about 170 LF of line for a commercial building. We had a question as to what would be acceptable for a slope PLF of this distance with limited fall. The Engineer came back with modifying the size of the drain from 4" to 6". And an overall reduction of fall to be at 1/4" PLF. 1/4" being the minimum fall PLF, if your landscape gradually declines towards your septic you really should have no problem. If your fall PLF is at least 1/4" and your line is at least 4" in Dia. That would most likely be adequate. Greater than 1/4" PLF of fall you will have no problems. Happy toileting!