How to Build a Septic Tank
A septic tank is a transfer point for waste coming from a structure. The tank accepts fluids and wastes and distributes them to designated areas for decomposition by micro-organisms. The process of constructing a septic tank is highly regulated because of health issues. Make sure all proper permitting practices are followed, or expect extreme cost overruns.
Required Materials
- sand
- gravel
- perforated/regular PVC piping & ends
- PVC glue
- tank – cement or plastic
Required Tools
- backhoe
- shovel
- string
- stakes
- pencil/paper
- tape measure
- paint brushes of various sizes
- surveying equipment
- measuring pole
Instructions
- Layout and Approvals - Approvals are something you will want to pay very close attention to with this project; one missed signature can be exceedingly expensive. Always make sure that you have every signature. Make copies just in case.
- Sketches - As you begin this advanced project, make a sketch with rough but close distances of the entire property lot. Locate any structures (and number of bedrooms), plantings, poles, power transformers, fences, lot lines, rights-of-way, large rocks, and slopes. Apply to the building/health departments and receive preliminary approval for a number of test pits to be dug.
- Test Pits - Once upon a time, a single test sufficed for a septic tank soil test. Although there may be a few places where this is still acceptable, most municipalities require several test pits to be dug. Try to convince a contractor that the likelihood of a possible job goes up if he helps dig the pits. Otherwise, hire a backhoe and dig pits where directed, and then arrange for an inspection. Try to coordinate so that the holes have just been dug as the inspector arrives. The inspection won’t take more than 20 minutes and the backhoe can refill the test pits when done. In some instances, the soil will simply not meet code. In this case, the inspection will take longer as new test pits need to be dug.
- Design, Location, and Digging - Obtain requirements from health/building departments and have the design drawn to meet these requirements. Then receive approval for the location of the septic tank. Begin digging the septic tank with a backhoe; once an in-site layout is complete, survey the project to determine final grade.
- Grade, Stone, and Pipe - Follow the design with sand, stone, and piping. Make sure the grade meets the plan. Now sand and stone the tank area to design. If a cement tank is used, hire a crane to install it. Timing is critical, as the crane and tank should arrive at the same time when possible. Lay and install the tank to design. Attach the piping to the house. Seek approvals again.
- Backfill - Before you even think about fully backfilling the trenches and holes, check to make sure that all permits and signatures have been put in the correct places. This is where many septic tank systems become very expensive - the owner thinks that all is done, but a signature has been missed. This means the whole system needs to be dug up and re-inspected. The fill that you use needs to be approved as well - check the design for the sand and stone layout.