This tutorial will teach you the basics of designing and installing a septic tank. This is not a job for the inexperienced do-it-yourselfer. You do need some backhoe and crane or construction experience or you could run into trouble quickly. If you have a friend you could bribe with an offer of dinner, their experience can work in your favor.
First and most important, you must check with the proper authorities: State, County, City and any other local persons such as mobile home park owner, subdivision group, community council, etc. This is to ensure that your property meets the minimum requirements for the installation of a septic tank. You will need to inform them of the size of the tank and drainage (or leach) field you intend to put in. Other considerations you need to consider are: setbacks, limiting soil features, maintenance access and possible replacement or expansion in the near future. Any or all of these may prove a stumbling block to you in your quest.
You will need to layout your system on a scale drawing of the lot where the system is to be installed. This will let you know if you have the minimum size lot necessary. In most, but not all, cases, at least 3/4 of an acre is needed.
You need to determine the height of the seasonal high water table or limiting soil layer. This will determine if you have the depth necessary to design and install the septic tank you are planning. You must have, at a bare minimum, at least 4 feet from the limiting soil feature.
Another factor to consider is the layout of the septic tank and drain field. Remember, maintenance vehicles that come to clean out the tank periodically are very heavy vehicles. You don't want them driving over any part of the tank or pipes leading to the tank or drain field.
Once you have done all this, draw out and locate your tank and field on a plot map. Submit this, with all other paperwork, to the proper authorities. They will go over the papers and design drawing, and contact you to let you know of any changes or further information they need, or to give you permission.
Once you have done all the paperwork and have the necessary permits granted, contact the local utilities to let them know you plan to dig. They will send someone out to mark their locations underground so you will know where to avoid. Mark out your planned excavations on the ground with chalk or white paint and get ready.
Your installation will proceed in three steps: Pipes from house to tank, septic tank and drain field. Make sure you excavate the proper drop from the house to the tank so the sludge will flow downhill. The tank should be installed by a contractor with experience, as tanks are heavy and can cause serious injury or death if mishandled. From the tank to the drain field you must also have the proper downgrade and setbacks.
Once you've installed everything and all areas are checked for leaks, you are ready to cover it all up again. Make sure you mark the locations of the tank vent and drain covers. That makes it easier to dig up for the maintenance of the tank.
That's it for the basic design and installation of a septic tank. If you want to get into this area with more detail, please contact me. I will be happy to provide you with all kinds of tables you will need in order to properly design, install and maintain your septic tank.