Measure your leach field. The field must have 500 feet of pipe for each bedroom in the home. You will want at least three pipes coming off the central leach pipe that leaves the septic tank and passes through the distribution box. That means you will have approximately 170 feet of leach field. Mark off your measurements using stakes hammered into the ground.
Use a backhoe to speed digging. You can do it by hand but the dimensions will make it a huge and tiring job. Dig out the rough dimensions of the leach field with the machine. Dig down 36 inches. Use a shovel to finish any edges and then rake the bed even.
Add 17 inches of gravel to the leach field bed and rake it smooth. Measure the pipes for the correct footage and mark with a pencil where you need to cut them. If you are doing a three-pipe system you need 170 feet of pipe cut three times. You will need to cut several pieces of pipe to add up to 170-foot total leach pipe.
Smear silicone around individual sections and add them together to make the three pipes in complete lengths. Lay them out in the leach field. Connect them to elbows at the distribution box. Use more silicone to ensure a waterproof seal.
Spread 17 inches of backfill over the pipes. Use the rake to even it out. Check your leach field often for standing water, odor or any other problems. Have the tank pumped every two to five years. Don't do all the laundry in one day as this will overload the drainage field. Never put fat or oil in your household drains as this may clog the pipes.