How to Make a Homemade Septic System

Septic System Drawing

The manner in which septic systems work is simple, but building one is a major undertaking. A backhoe is essential for the excavation. Digging a leach field by hand would take weeks, if not months. Site-selection is crucial, as vehicular traffic driving over the completed site could easily damage the piping and tree roots will eventually plug the system. Before beginning construction, check your local building codes and obtain all permits.

Things You'll Need

• Backhoe
• Shovel
• Rake
• Tape measure
• Septic tank
• ASTM Schedule 40 pipe
• Perforated leech field pipe
• Distribution box
• Bubble level
• 3/4-inch gravel
• Straw or a geotech material

Instructions

1. Determine the size of the septic tank for your family. Generally, a 1,000-gallon tank is required by most building codes for a two-bedroom home, while a 1,500-gallon tank is the minimum for a four-bedroom home. Bigger is better when it comes to septic systems.

   The size of the leach field is determined by the soil percolation rate. A 4,500-square-foot field is ample for oil that percolates at a rate of 3-inches per hour, but soil that only percolates at 1-inch per hour should have a 9,000-square-foot field.

2. Stake the location of the tank and corners of the leach field. Excavate to a depth that will allow for the fall of 1/4-inch per foot for all piping and the perforated leach field pipes. Stockpile spoil near the site for convenient backfilling. Calculate the amount of 3/4-inch rock needed for a minimum of 1-foot of base to be installed under the leach piping. For a 5,000-square-foot field, divide by 27, which gives you the number of cubic yards needed; in this case, 185 yards. A 9,000-square-foot field will take 333 cubic yards.

3. Before setting the septic tank, level and compact the soil. Add 6-inches of rock, level and compact again. Install the tank and distribution box, or D-box. The D-box distributes the waste water evenly to all leach field pipes. Install at least 1-foot of leach rock, but do not compact. Install the 4-inch perforated leach field pipes. Over the top of the leach pipes, evenly spread using a rake, straw to a depth of 1-foot to prevent dirt from clogging the pipes. There are textile materials that can be used and are available at most building outlets.

4. Backfill the excavated areas and grade the work area to match existing landscape. Export remaining spoils.

Tips & Warnings

• Before purchasing the leach rock, try to negotiate a deal with the trucking company to also export the spoils.

• Obtain building permits. Obtain inspections as required. Use only an experienced backhoe operator.