The septic system is a two-part sewage treatment and disposal system buried in the ground. It is composed of a septic tank and a soil drain field. The sewage flows by gravity into the septic tank where the solids are removed: the liquid then flows to soil drain field where it is allowed to soak into the ground.

The conventional septic tank is usually a concrete, fiberglass or plastic watertight structure where the wastewater from toilets, bathtubs, showers, laundry and the kitchen collects. It is designed to hold long enough to for most of the heavy suspended materials such as fecal matter, soil, grit, and food residues to sink to the bottom of the tank to form sludge. At the same time, lighter materials such as grease, fats and paper products float to the top of the tank where they remain trapped between the inlet and outlet pipes. The wastewater or effluent is pushed out of the tank. The effluent, containing organic matter and high numbers of bacteria and viruses, is discharged into the underground piping network called drainfield or leach field.

Solid materials will, over a period of time, settle to the bottom of tank or float to the top. Bacteria that live in the absence of oxygen break down the solid material. The rate of decomposition or breakdown varies. Some organic materials decompose very slowly and others such as plastics, metals and other inorganic materials do not decompose at all.

Stories of septic tanks that have never been pumped are the exception to the rule. The septic drainfield will last much longer if a regular maintenance schedule is followed rather than waiting for signs of failure to develop. Once signs of failure occur, expensive repairs may result. The main obstacle to effective septic tank maintenance is its "out of sight, out of mind" characteristic. There are few signs that something is wrong until the effluent has surfaced or the fixtures do not drain. If sludge and scum are not removed from the tank, they build up, and particles will be washed out into the drain field where they prematurely clog the soil, thereby requiring expensive repairs.

Some systems may not need maintenance for several years while others may need it every 2 years, due partly to the particular habits of individual households. It is important to periodically pump a septic system. It is recommended that the septic tank be pumped every 3 to 5 years.

If you are not sure where your septic tank system is, consult your Greenlee County Environmental Health Division office. If your house is not too old, the office may have a record of where your septic tank is located in reference to your house. Another way would be to probe the yard to see if you can physically locate it. Your yard may contain certain clues, such as a cleanout pipe poking out of the ground on the side of the house where the septic tank is located. This line leads directly to the tank, which is usually 10 feet or more from the foundation of the house. A plumber or septic tank pumping company can also locate the tank for you.

Pumping a septic tank involves digging a hole over the tank so that the manhole or lid to the tank can be opened. The pumping contractor dig it up for you, but this can be more expensive. The manhole or lid is usually located 12 inches or more below the ground surface. Once the tank is uncovered and opened, the contents of the tank are pumped into a truck. The liquid/solid mixture, called septage, must be disposed of at an approved disposal site, usually a sewage treatment plant.

Contractors are listed in the telephone book (in the yellow pages under “Septic Tanks & Systems - Cleaning”).

The efficiency of the septic system is related to the length of time the wastewater is retained in the tank. The more water is used, the faster it goes through the system. The less water used, the slower it goes through the tank, and the longer the solids have to settle out so that they are not passed on to the drain field. Repair all leaking fixtures as soon as possible.

When used in normal quantities, household cleaning products would not have any harmful effects. Pesticides, herbicides, paint, solvents or oils should not be disposed of in the septic system.

Chemicals, yeasts, bacteria enzymes or other substances cannot eliminate or reduce the solids or scum in a septic tank so that periodic cleaning becomes unnecessary. Addition of chemicals is not recommended.

The drain field (leach field, disposal trench or subsurface disposal field) is and underground piping network buried in trenches below the surface of the ground. The field distributes the effluent from the septic tank over a large soil area allowing it to percolate through the soil. The soil acts as a filter and disinfectant by removing most of the pollutants and disease causing viruses and bacteria found in the effluent.

The major pollutants are disease causing viruses, bacteria, nitrates and phosphates. The soil does a good job of removing bacteria and viruses. Such organisms do not survive long in well-drained soil. When soils are not well drained, disease-causing organisms are not as quickly removed and can travel long distances from the drain field. Effluent contains phosphates and nitrates similar to commercial fertilizers. Phosphates are usually removed by the soil and present few problems unless the system is near a body of water or stream. Nitrates usually pass through the soil concentrating in groundwater tables. High concentrations of nitrates in drinking water can be unhealthy, particularly to babies and young children.

Drain field failure is usually indicated by either the backing up of sewage into the home or by surfacing effluent the drain field area. This effluent usually has a very offensive odor. Surfacing effluent usually turns black or gray. Another symptom is slow draining household fixtures. When this occurs, the septic tank may need pumping or the drain field's ability to handle the inflow of effluent is decreasing.

Sooner or later all drain field systems will fail. Because a drain field is basically an underground filter, eventually the filter will clog. The homeowner need to be careful about the materials flushed into the septic tank. Some of the things to keep in mind are:

• Reduce the amount of wastewater discharged into the system by changing use habits or utilizing water conservation devices.
• Be careful of the types and amounts of harmful materials flushed into the tank. Materials such as oil, grease, fat, matches, cigarette butts, paper products, disposable diapers and sanitary napkins, should not be flushed into the septic tank.
• Pump the septic tank regularly.