Since improperly maintained and failing septic systems are common sources of water
pollution and since all septic systems will fail sooner or later, the following
questions have been compiled to help you understand and maintain your septic system.
What is a septic system?
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.
What is a septic tank?
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.
What happens to the solid materials in the tank?
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.
Why should I maintain my septic system?
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.
How often is maintenance neeeded?
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.
How can I locate my septic tank?
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.
What is involved in pumping a septic tank?
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.
Who pumps septic tanks?
Contractors are listed in the telephone book (in the yellow pages under “Septic
Tanks & Systems - Cleaning”).
How does water affect my septic system?
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.
Will bleaches, drain cleaners and detergents harm the bacteria in the tank?
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.
Do septic tank additives help?
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.
What is a drain field?
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
What does removes “most” of the pollutants mean?
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.
How can I tell if my system is failing?
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.
How can I prevent or delay drain field failures?
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.