Installing the Septic System

The installation of a septic system consists of two main parts.  The first involves the septic tank.  The second concerns the drain field.  Professional help is available from a competent plumber.

Before proceeding a couple of preliminary steps are necessary.  Most of these are covered in the initial design of the wastewater treatment design.  To continue with the process, the next step is to apply for a septic tank permit from your local jurisdiction (State, County, City, Subdivision).  After obtaining an approved one, the actual construction of the septic system can commence.

A good first step is to acquire the necessary materials needed to layout your system on the ground.  This usually consists of a tape measure, string, stakes, and white spray paint.  These are helpful in outlining the system on the ground before the actual digging begins.

The construction part consists of three major sections.  These are 1) the pipe from the house to the tank, 2) the septic tank itself, and 3) the drainfield.

Pipe Connecting House to Tank

The pipe itself is usually  3 or 4 inches in diameter and is laid in a graded trench starting from the house.   The trench should be free of rock and is often sand or a native material.  The pipe  should fall at the rate of 1/4 inch per foot.  It is often advisable to install clean outs where they are easily accessible by the homeowner. Prior to laying the last piece of pipe the tank itself should be put in place.

Installing the Septic Tank

Although there are several options regarding the materials used in the making of the septic tank, the one most common is concrete.  The plumber doing the installation will be responsible for digging the appropriate size hole and placing the tank once the hole has been completed.  Before the tank is set in the hole, make sure that any large rocks have been removed and the bed has been properly leveled.  After the tank has been put in place, carefully inspect it for any damage.

The next step is to install the inlet pipe, the outlet pipe and the cover.  Water should then be used to fill the tank to make sure it is watertight and because it needs to be full to properly operate.  Backfilling can then commence.  Soil should be crowned over the tank at least 6 inches high to divert runoff and allow for settling.

Drainfield Construction

Before beginning it is necessary to make sure that the soil is not too wet to excavate, otherwise the system will not operate correctly.  The trenches can then be excavated according to the specifications in the system design.  It is important to ensure that the trench is constructed with no slope and is level – within 3 inches per 100 feet.

The 4 inch perforated distribution line is then placed with the perforations at 4 and 8 o’clock.  Further, the ends of each line should be capped.  Next an approved aggregate is put on top of the pipe at least 2 inches deep.

If there are more than two trenches, a distribution box may be required by the local authorities.  The key point in placing the distribution box is to ensure that it is level.  If not, and even distribution will not result.

Upon backfilling the trenches the pipe drainfield is not complete.

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