Categories: HOME IMPROVEMENT

How to Build a Septic System

Rules and regulations on how to build a septic system vary from state to state but the basic construction is the same. Earth compaction and frost lines vary in different areas, requiring tests to determine absorbency.

Perk Test

A perk test determines the absorbency of the soil and requires a sample of the soil from deep in the ground, where the septic system will be constructed. The sample is usually attained with a backhoe, from a depth of seven to eight feet. The perk test determines the amount of leach bed required to absorb water from a particular sized building or residence.

Assembly of Septic system

Assembling your septic system requires a backhoe. Components for your system can be found here. Dig a hole, two feet wider and two feet longer than the septic tank and at least ten feet from the house. The depth depends on the terrain where the septic tank will be located. The receiver hole in the septic tank must be lower than the sewer pipe exiting the house. The top of the tank should be one foot underground. The bottom of the hole must be leveled with a 1-inch drop from inlet to outlet.

Your tanks will be delivered by a truck and unloaded into the hole. Concrete tanks have an adjustable knockout in each end. Insert an 18-inch piece of 4-inch solid PVC sewer pipe into the entrance end of the tank. Attach an adapter for a 3-inch to a 4-inch pipe, using clear PVC glue, to the outside end of the insert.

Dig a trench from the exit line on the house to the receiver end of the tank. All septic system pipes have printing on one side if the pipe. Install all sewer pipes with the writing side up, so the inspector can see that you used the proper pipe. Glue a 4-foot length of 3-inch ABS pipe to the outlet pipe of the house. Glue a 2-way cleanout to the 4-foot ABS pipe. Connect the tank to the exit line of the house using 3-inch ABS black sewer pipe. Be sure that the line runs downhill from the house to the tank.

Remove the lid on the tank and glue a 4-inch sanitary T to the incoming pipe on the inside of the tank. Your tank is now attached to the house. Shade in the pipe from the septic tank to the house with loose dirt to hold the pipe in place. Be sure that the writing on the pipe shows above the dirt, so the inspector can see it.

Dig a trench from the exit end of the septic tank to the beginning of the leach bed. Be sure that the trench slopes downhill from the septic tank. Continue the trench at a depth of six feet for the specified length of the leach bed. Fill the leach bed trench with leach rock to a depth of four feet and level the leach rock in the trench. (A level surface is critical)

Insert a 4-inch PVC solid sewer pipe about 14 inches into the exit end of the tank. Be sure the pipe slopes down, from the tank to the leach field. If the leach field runs straight out from the tank, attach a 22 ½-degree elbow to the end of the solid line. Glue the required length of 4-inch perforated sewer pipe together with the lettering on the pipe on top so that the holes are on the bottom. Glue an end cap at the far end of the perforated pipe. Place pipe into the center of the leach bed with letters up and glue the open end to the solid pipe coming from the septic tank.