How to Put in Septic Tanks

Installing a septic tank requires a team of workers.

Installing a septic system requires large equipment and forethought. The installation process involves heavy construction machinery. The septic tank itself weighs hundreds of pounds. Tank installation involves the tank itself and preparing and equipping a leech field. The leech field is the area where the water soaks back into the ground, filtered by earth and sand. In addition to the tank and leech field, every septic system must attach to the household plumbing system. Before attempting to install a septic tank, check with your local authorities for any permits needed.

Things You'll Need

• Soil core sampler
• Shovel
• Gravel
• Ruler
• Backhoe
• 4-inch PVC pipe
• D box
• PVC leech pipe

Instructions

1. Remove soil cores from the area to determine the ground composition. Sandy soils are better than clay soils at filtering and draining water from the septic tank. Dig four to six holes 18-inches deep in the area designated for the septic tank. Place 2 inches of gravel in the bottom of the hole. Fill the hole with 12 inches of water. Allow the water to soak into the soil for 24 hours. Fill each hole with 8 inches of water. Measure the water level every 30 minutes.

   According to the University of Missouri, calculate 150 square feet for every room of the house if the water is absorbed at the rate of 1 inch every 10 minutes. Calculate 200 square feet for each room for an absorption rate of 11 to 30 minutes. Calculate 300 square feet per room for an absorption rate of 1 inch every 30 to 60 minutes. Water absorption rates slower than one inch per hour must be tested by a licensed soil professional.

2. Dig a hole for the septic tank with a backhoe. Dig the hole deep enough to not only fit the septic tank, but also deep enough to cover the tank with a foot of soil. Dig the trenches for the leech field. Use a laser level to make sure that the drains slope 1/4 inch per foot of drain pipe.

3. Lower the septic tank into the hole. Insert the sewer outlet from the building into the septic tank. Follow the manufacturer's direction for installing the electrical pump if included in the septic tank.

4. Cut 28 inches of 4-inch PVC pipe. Place one end of the pipe in the outgoing seal at the top of the septic tank. Place the other end into the seals in the D box. Both holes have special seals that do not require glue or other special adhesives.

5. Fill the leech trenches with gravel. Lay the PVC leech pipe on top of the gravel. Check the grade with the laser level to make sure that each pipe slopes away from the tank at least 1/4 inch per foot the entire length of the pipe.

6. Cover the septic tank and the leech pipes with soil. If using a backhoe, exercise caution to prevent driving the vehicle over the PVC pipes or septic tank. Landscape or sod the area as desired.

Tips & Warnings

• After installing your septic tan, be sure to care for it. A septic tank is designed to break down solid waste with bacteria. Do not use bleach or other harsh chemicals that may kill or slow the action of the natural bacteria.

• Check with your building license office. Some communities require specific permits before installing a septic tank. Some communities will allow no one but a licensed sewage expert to install a septic tank.

References

• Eco-Nomic: How To Build Septic Tank Systems
• Separtment of Soil Science, North Carolina State University: Septic Systems and Their Maintenance
• The Natural Home: Septic Tank Designs
• Universtiy of Missouri: Septic Tank/Absorption Field Systems