is a Septic System?
septic system is a small scale wastewater and sewage treatment
system common in rural areas where connection to city sewer
lines is minimal or non-existent. An anaerobic bacterial
environment, that is, one existing without the presence of
oxygen, causes decomposition of the waste discharged into the
system. The septic system is designed to remove, and treat,
then slowly release wastewater over an area of land to be
absorbed by the soil.
Features & Functions
substances disposed of via any drain in the home will flow
through the plumbing to the septic tank.
septic tank is a solid holding tank usually constructed of
concrete, fiberglass, steel, or polyethylene, designed
specifically to accept all wastewater from the home, and
ranges in capacity from 750 to 1,500 gallons based upon the
size of the residence. Most homes have one large tank with two
of which is equipped with a lid located approximately three
feet beneath ground level, or which may be fitted with lid
risers that extend above ground level to accommodate access to
the tank compartments for inspection and cleaning. The
compartments are separated by means of a dividing wall, which
has an opening midway between the floor and roof of the tank.
septic tank connects the plumbing from the home, through the
inlet pipe, also called the inlet baffle, to the absorption
area, through the outlet pipe, or outlet baffle.
inlet and outlet baffles are designed in the form of a T to
allow liquid entry and egress without disturbing the forming
layers of bacteria, nor allowing thick particles to travel
back into the plumbing, inevitably causing a clog. Wastewater
enters the first chamber of the tank, known as the solid side,
and begins to separate into one of three layers:
of soaps, greases, toilet paper, and other organic solid
materials that float to the surface to decompose and
eventually join the liquid layer.
Layer consists of
fairly clear water, separating the scum layer and the sludge,
which flows through the opening in the dividing wall and into
the second compartment, also known as the liquid side, for
of heavy, inorganic, solid materials that sink to the bottom
of the tank, and continue to build-up until cleaning takes
operating properly, the septic tank should maintain a full
wastewater level, just below the inlet and outlet baffles.
Every time untreated wastewater flows into the tank, an equal
amount of treated wastewater flows out.
treatment of wastewater occurs in the soil. Soil treatment
kills disease-causing organisms in the sewage and removes
nutrients through percolation of the clear water flowing from
the septic tank.
two most commonly used types of absorption areas are the
seepage pit and the leach field.
of a concrete block cylinder with a closed top and open
bottom, positioned vertically underground, surrounded by a
layer of rock. The pit measures approximately 5’ in diameter
and ranges in depth from 20’ to 38’ depending on the size
of the residence.
consists of a rock-filled, underground trench through
which a perforated pipe line runs. The leach line ranges in
length depending on the size of the residence and percolation
rate of the soil.
all waste can be decomposed by the anaerobic digestion in a
septic tank. The sludge, or accumulation of heavy, inorganic,
solid materials that sink to the bottom of the tank, must be
periodically pumped out. If allowed to build-up, the sludge
will eventually flow into the absorption area, causing system
failure. Once any solid material has passed into the
absorption area, the tiny percolation holes, used to treat the
waste-water, will become clogged, causing system failure and
requiring expensive repairs. Unfortunately, no signs of
distress to your system will be obvious until the clog
backs-up into the home, when the absorption area is often
already destroyed, and relocation is necessary. Meanwhile, any
solid materials escaping through the absorption area into the
surrounding gravel, contain toxins that harm the environment.
pumping will remove scum, sludge, and liquid from both
compartments of the septic tank. The tank is then flushed
clean using a high-pressured hose. Any film left on the tank
walls or liquid left on the tank floor contains millions of
bacteria necessary to ensure anaerobic decomposition will
continue once the tank is re-filled. With regular use, the
tank will naturally re-fill to normal operating level within
Bernardino County Department of public health recommends that
you, “have your [septic] tank pumped every two to four
years.” Never go longer than 48 months between pumps.
is extremely important to monitor the substances washed down
the drain and into your septic system. The following list of
items should be avoided at all costs:
Oils & Grease
accumulate too heavily on the top layer of the tank, blocking
the inlet and outlet baffles, and can form a thick coating
throughout the plumbing, causing unwanted clogging.
cotton swabs, q-tips, dental floss, paper towels, cigarette
butts, cat litter, feminine hygiene products, contraceptives,
baby wipes, and diapers should be disposed of elsewhere or the
system will rapidly become clogged.
too much undigested food solids to enter the system,
decomposition process and causing overload.
salt to water high in calcium, which in turn, destroys needed
& Cleaning Solvents
pesticides, herbicides, bleach, disinfectants, acids, anti-septics,
paint, medications, anti-biotics, anti-bacterials, waxes or
polish, oil, and other non-water soluble, toxins kill the
bacteria needed to create the proper environment for
Drains allowing wastewater to enter the system should be
equipped with strainers and other filtration devices to reduce
the amount of food particles, hair, lint, and other inorganic,
solid materials that do not decompose or which may clog your
Start a compost pile to discard unwanted food rather than
using a garbage disposal.
Use minimal amounts of toilet paper.
total amount of water and the pattern of water use affects how
the septic system works. For complete and uniform treatment of
wastes, the system needs time to work. Each time wastewater
enters the septic tank, an equal amount of wastewater leaves
the tank and flows to the absorption area. Sudden or large
volumes of water entering the system in a short period of time
may agitate and re-suspend sludge and scum into the liquid
contents. If this happens, suspended solids can be carried
into the absorption area, clogging soil pores and diminishing
the soil’s ability to accept water.
a portable toilet or have your septic tank pumped a few days
before hosting a large party to prevent likely overload.
water use puts an unnecessary load on the septic system.
Allowing faucets to drip, fixtures to leak, and using running
water to wash and rinse dishes, shave, and brush teeth are
wasteful water habits. In most households, toilet flushing is
the largest user of water, followed by bathing, and laundry.
a low-flow toilet which uses only 1˝ gallons of water per
flush, as opposed to the 6 gallons per flush of a standard
leaky faucets and running toilets immediately.
toilets less often.
a shower which, in 10 minutes, will use an average of 25
gallons of water, rather than a bath, which uses twice as
low-flow, hand held shower heads with pause control.
only full loads in the dishwasher and washing machine.
use of cleaning solvents by doing more scrubbing with less
off water while shaving, brushing teeth, or rinsing dishes.
liquid detergent, with less than 5% phosphate, in the
dishwasher and washing machine.
a front-loading washing machine, which uses approximately 25
gallons of water per load, as opposed to the 40-60 gallons per
load of a top-loading model.
wash loads evenly throughout the week to avoid overloading the
system with large volumes of water.
your water pipes to avoid wasting water while waiting for a
using running water to thaw meat or other frozen foods.
heavy vehicles over the absorption area can cause damage.
Likewise, building a playground, shed, patio, or other
structures atop the septic system can do the same. Soil
treatment depends on undisturbed, non compacted, unsaturated
soil to treat wastes. Nothing heavier than a riding lawnmower
should be driven over any part of the septic system.
Do not plant trees or other plants with deep, invasive roots
within twelve feet of the septic system.
Roots are a major cause of unwanted clogs and
destruction of the septic tank and absorption area. Consider
the mature size of trees and shrubs when planting young
enter the septic tank. The tank has two lids used to pump and
inspect from the outside only. The tank contains very little
oxygen and has high levels of hydrogen sulfide, methane,
carbon dioxide, and other life-threatening gases.
smoke near septic tank openings. Gases such as methane that
may be present are potentially combustible.
seepage pit can reach depths of up to 38 feet. Keep children
and other spectators away from the septic system when it is
being excavated and pumped.
For more information please
visit the United States Environmental Protection Agency's
[ http://water.epa.gov/infrastructure/septic/septicsmart.cfm ]