What is a Septic System?
A typical household sewage treatment system consists of a house sewer, septic tank, distribution box and absorption fields or seepage pits.

What are the components of a Septic System?
The house sewer is the pipeline connecting the house and the septic tank.

The septic tank is where untreated liquid household wastes (sewage) will quickly clog your absorption field if not properly treated.  The septic tank provides this needed treatment.  When sewage enters the septic tank, the heavy solids, fats and greases partially decompose and rise to the surface and form a layer of scum.  The solids that have settled to the bottom are attacked by bacteria and form a sludge.  Septic tanks do not remove bacteria and, therefore, what is discharged cannot be considered safe.
The distribution box serves to distribute the flow from the septic tank evenly to the absorption fields or seepage pits.  It is important that each trench or pit receive an equal amount of flow.  This prevents overloading of one part of the system.
The absorption field is a system of narrow trenches partially filled with a bed of washed gravel or crushed stone into which perforated pipe is placed.  The discharge from the septic tank is distributed through these pipes into the trenches and the surrounding soil.  The subsurface absorption field must be properly sized and constructed to assure satisfactory operation and a long life.

The seepage pit is a covered pit with perforated sides through which the discharge from the septic tank infiltrates into the surrounding soil.  It is generally installed in sandy or gravel-type soils.  Like the absorption field, the seepage pit must also be properly sized and constructed.  While seepage pits normally require less land area to install, they should be used only where absorption fields are not suitable and well water supplies are not endangered.

Tips for operating and maintaining your Septic System
In many neighborhoods in Westchester County, individual household sewage treatment systems are used for the disposal of household wastes.  As a homeowner using a septic system, there are a few things you should be aware of;

• The contents of your septic tank should be pumped every two to three years or when the total depth of sludge and scum exceeds one-third of the liquid depth of the tank. If the tank is not cleaned periodically, the solids are carried into the absorption field; rapid clogging occurs; premature failure follows and finally, the absorption fields must be replaced.
• Pumping your septic tank is less expensive than replacing your absorption field.
• Detergents, kitchen wastes, laundry wastes and household chemicals in normal amounts do not affect the proper operation of household sewage treatment systems. However, excessive quantities can be harmful.
• Garbage grinders substantially increase the accumulation of solids in the septic tank, as well as the solids entering the absorption fields and pits. Their disadvantages outweigh the convenience they provide and are not recommended for households with their own sewage treatment systems. If used, the septic tank size should be increased.
• All of your laundry wastes must be connected to the septic system.
• Do not dispose cigarette butts, disposable diapers, sanitary napkins, plastics, trash, etc., into your household sewage system. These items do not readily decompose.
• Septic tank additives are not recommended. Additives are not necessary for the proper operation of household systems and may cause the sludge and scum in the septic tank to be discharged into the absorption field, resulting in premature failure. 
• Backwash from water softeners may be discharged to the septic tank and absorption system if discharged at low daily volumes.
• All roof, cellar and footing drainage and surface water must be excluded from the household treatment system. This drainage water can be discharged to the ground surface without treatment; make sure it drains away from your sewage treatment system.
• Roots from trees in the immediate area of the absorption field may clog the system.
• Keep swimming pools (above or in ground) away from the absorption field.

Septic System Cautions
- DO NOT enter your septic tank. Individuals have died from gas asphyxiation.
- Never permit heavy equipment to pass over the absorption field.
- Conserve your water usage; this can prolong the life of your sewage treatment system. Replace defective toilet tank valves, repair leaky fixtures, install appliances and fixtures that use less water and avoid wasteful practices.
- Your sewage treatment system is normally designed to accommodate two persons per bedroom. If your household is larger than this, or if you add additional bedrooms, enlarge the system.
- If surface water from higher ground is running onto your absorption field, install a ditch or berm to intercept this surface water.