How to Build a DIY Septic Tank System


Build Septic Tank System

To save homeowners the cost of hiring a professional septic designer and excavator, you can build a septic tank system yourself. The installation of new septic systems is expensive even if you build your own DIY septic tank and drainage systems by hand. But still you could save money by installing a septic tank system yourself.

Costs of a DIY Septic System

Connecting a waste disposal system to a septic tank is important for health and hygiene. If your home is located in a place where there is still no underground sewerage system, a septic system will be necessary

. Public health fees for permits to build a septic tank system largly depends upon which county you live in, but you will likely not be able to avoid paying for the permit.

To determine the retail costs of your DIY septic system design, including: drain field, distribution box and pipes depends on the price of the building materials. These building materials tend to vary in price dependent on the hardware store to you go to. Be sure to make a comparison of your local hardware and diy stores to save yourself a lot of money. On top of that you will have the excavation to think of.

Before You Start Digging

It is always a good idea to make a proper evaluation of the job at hand before you start the actual construction work. Before you get your shovel out and start digging holes it would be a good idea to first get yourself a scale map of your home and property.

The best place to build a residential septic system is the backyard, underneath the garage, or any side adjacent to a street.

Septic Tank Installation - First

Selecting the location before you start digging the hole for the septic systemis a vital step in the process. Mistakes made in the installation of the septic tank can result in system failure and not only costly repairs, but a very nasty situation to endure. It is critical to get the tank installed correctly, the first time.

The Site Evaluation

The traditional perc test has been replaced by a site evaluation in most states as a way to provide a demonstration to your local health department of the treatment qualities of your property.

DIY Perc Testing

Traditionally the perc test was done simply by pouring a bucket of water into a small hole in the ground and then timing how fast the water soaks up into the soil with a stop-watch. The site evaluation is done down in a 6 foot deep hole. Where as the perc test only shows you the absorption speed of a small spot of the property, the site evaluation tests a much wider area across the soil face.

Soil Classification

The soil classification system that is being used in almost all states in the USA, is the US Department of Agriculture Soil Conservation Classification System. Most soil testing pits contain 3 or more different types of soil as you continue to look down through the soil.

Septic Tank Installation - SecondDrainfield Trench Size

The drainfield size is not dependent on the number of bathrooms or fixtures on the property. To establish the flow rate, almost all health departments use:

  • The number of bedrooms there are in a home
  • The number of people in the house
  • The usual daily water use

This flow rate determines the amount of sewage that must be sent to the drainfield. Once you have determined the type of soil under your future drainfield, look up the drainfield area required for your house size in the chart found here and you will have the required drainfield size.

Size of The Septic Tank

The dimensions for a septic tank construction are determined by the size of the family and/or property it is intended for. Consult the metric standards for the locality where the construction is to be located. This is the best way to find out what size septic tank you should use to build your own septic tank system. The size of your septic system will also determine the frquency with which you will need to have your DIY septic system pumped by a professional septic pumping service.

Creating the Drawings

Before we can start building our septic system we need to create the drawings as to meet the needs of your local health department. The actual level of detail that is required for your DIY septic system drawings may vary from state to state. However, all buildings, walkways, property lines, retaining walls and the location of the original test holes must be shown.

Drainfield Layout

Your drainfield layout will require a minimum of 2 trenches of equal size. The separation of the water flow into two, three or more lines is accomplished with a distribution box aka. D-box to divide the flow. The distribution box uses pipes equipped with flow control valves in the form of eccentric plugs that evenly split the flow between multiple drain lines. The effluent has to flow downhill from the tank outlet, through the distribution box and down the individual trenches. These trenches should be dead leveled so the water spills out onto the floor of each trench.

Apply for a Building Permit

Now you have the drawing, you should submit your plans to the office of the local health department. You will have to fill out the application form and pay the corresponding permit fee. After that you will need to wait for the drawings to be reviewed by the board and get approved before going on into the final construction phase.

Building a Septic Tank System

The first step of the building process is to create a basic layout of the septic system. This layout is used to transfer your building plans to the ground. The Layout and location of all the different parts of the septic design must be projected onto the site.

Septic Tank Installation - ThirdExcavation of the Septic Tank System

When it comes to excavating the site to prepare for the installation of the septic tank and drain lines, constant attention to elevation is required to get the best results. Once you are done all the excavating, you will need to make another appointment with the health inspector for a final inspection of the job before backfilling can begin.

Backfilling the Septic Tank System

All the tanks, the pipes and vaults should be backfilled around the sides during construction. Vacuum testing, pressure testing or water testing of all tanks may be required in your local jurisdiction. Also more and more counties are requiring leak testing of the tank nowadays. So the final backfilling of the concrete tanks can be postponed until the final inspection to check for leaks. The final backfilling should only be done after the final health department inspection.

External References

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