Install Toilet Distance From Wall' title='Install Toilet Distance From Wall' />How to Install a Septic System 1. Steps with PicturesFind where you want to go into the building relative to where you want to place the septic tank. Excavate to at least 2 feet deep and drill a hole through the wall, or go deeper and go under the footing, whichever is desired, or necessary. Plan for the flow to go downhill from here, as this is exactly what a gravity fed system is all about. Install Toilet Distance From Wall' title='Install Toilet Distance From Wall' />We posted a video demonstrating basic toilet repairs on the Apron blog. This prompted a question about choosing a toilet to install from reader Collette. Install Toilet Distance From Wall' title='Install Toilet Distance From Wall' />A fitting is used in pipe systems to connect straight pipe or tubing sections, adapt to different sizes or shapes and for other purposes, such as regulating or. It does not use a mechanical means other than gravity to discharge the waste from the tank to the drain field. Pipe 4 Sch. 4. 0 going a foot through the wall or under the footing, and to a minimum of five feet outside the building toward the tank. Set it level where its going through the wall or under the footing, and from there run with about an 18 per foot of pitch slope toward the septic tank. Go further or all the way into the tank if required. If not, switch to 4 3. Free Train The Trainer Certification Course. Be sure to put a test cap on the end going into the building. If going through the wall, seal around the hole with hydraulic cement, inside and out. Dont run too much pitch going out to the tank. If theres too much, the water runs away faster than the solids, and the solids may get left in the pipe. Also, there may not be enough pitch to get to the drain field, depending on the depth your drain field is, and how close it will be to the outlet of the tank.