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Bobcat-Septic Systems & Sand
Septic Care Questions
HOW DO SEPTIC TANKS WORK?
Septic tanks are watertight containers which remove large solids and greases, provide anaerobic digestion of the solids, and
storage of the sludge and scum. Septic tanks do not remove large numbers of bacteria and viruses. The sludge and scum layers
must be removed periodically to prevent the accumulated solids and greases from flowing into the soil absorption system and
clogging the soil pores. If washing machines, dishwashers, and garbage disposals are used, the amount of sludge will increase
and the septic tank will require frequent cleaning.
Effluent from the septic tank flows by gravity or is pumped to a leach field for disposal. A leach field consists of a series of
four-inch diameter perforated distribution pipelines placed in two to three foot wide trenches. The perforated pipe is placed on
top of gravel which is also used to backfill around the pipe. The gravel promotes drainage and reduces root growth near the
FAILING SYSTEMS: SYMPTOMS / CAUSES / REMEDIES
Water will not drain in showers & toilets / Ponding of wastewater over leach fields.
Solids or scum blocking septic tank inlet and outlet:
—Pump septic tank periodically
---Clean effluent filter, if one exists
Roots blocking pipelines:
—Contact commercial root remover services. Many chemicals may harm the septic system.
System hydraulically overloaded:
—Reduce water usage through water conservation.
—Reduce landscape irrigation of soils near leach field.
—Increase design capacity of leach field to meet actual use of septic system.
—Construct surface and subsurface drainage diversion facilities upstream of leach field.
—Construct new leach field in area without high groundwater.
Gravel clogged with fine soils:
Soils smeared due to obstruction during wet weather:
Damage due to heavy vehicles or objects:
—Replace leach field.
System constructed too close to cut bank
Gopher or rodent activity
—Replace leach field.
—Repair suspected area, possible replacement of leach field.
Odors from house vent or leach field:
—Atmospheric conditions may prevent dispersion of odors during early morning and late afternoon.
—Increase height of house vent to provide for better dispersion.
SEPTIC SYSTEM MAINTENANCE
Maintenance of the septic system primarily consists of removing the accumulated sludge on a periodic basis. Every
three years, the sludge and scum layer depths should be inspected. The septic tank should be pumped when the
bottom of the scum layer is within three inches of the bottom of the outlet pipe, or the distance between the top of the
sludge and the bottom of the outlet pipe is within the limits presented
Approximate Total Liquid Depth
Volume of Septic Tank 3ft. 4 ft. 5 ft.
800 gal. 6 in. 10 in. 13 in.
1150 4 in. 6 in. 8 in.
1500 4 in. 4 in. 6 in.
In addition, users of a septic system must observe the following basic rules in order to ensure satisfactory
...inspect and, if necessary, pump septic tank every three years.
...reduce the amount of water used during winter and spring when groundwater levels are high.
...minimize or eliminate the use of garbage grinders. This appliance adds extra solids and water to septic system.
...conduct percolation tests during wet weather season before installing a new system.
...flush semi or non-biodegradable items into septic tank, including paper towels, newspapers, writing paper, rags,
disposable diapers, or cat litter.
...wash down sides of septic tank when it is pumped. The remaining slime contains bacteria which will be needed to
digest the wastewater.
...flush large amounts of chlorine bleach or lye products into the septic tank. However, normal household use will not
harm the bacteria.
...pour used motor oil into the septic tank.
...discharge brine (salt water) waste from self-regenerating water softeners to the septic tank. The high salt
concentrations will clog the soil pores.
...connect roof drains and yard drains to septic tanks. Extra water will flood the tank and the leach field.
...add sodium hydroxide or potassium hydroxide to the septic tank. These chemicals will affect solids settling and
cause the sludge to flow into the leach field.
...construct leach field in close proximity to another leach field. The soil will become saturated and both systems will
...construct leach fields in impervious soils, near fractured bedrock, on steep slopes, or on flood plains.
...plant small or medium-sized trees within ten feet of leach fields or large—sized trees within 20 feet of leach fields.
Roots will clog the pipelines.
...plant vegetation which requires excessive amounts of water on top of the leach field.
...drive vehicles or place heavy objects, such as portable swimming pools, over septic tanks and leach fields. In
addition,- stakes-for-plants and supports for children's’ s swings should not be placed over septic tanks and leach
...discharge water from washing machines directly to the ground surface or leach fields. The wash water contains
chemicals and bacteria which will contaminate surface waters and cause a public health hazard. The wastewater also
contains fine solids and soap scums which will clog the soil pores. If the existing septic system will not accept water
from the washing machine, a separate septic tank and leach field must be installed.
COMMON MYTHS ABOUT SEPTIC SYSTEMS
Septic systems last forever and never need replacement.
Septic systems require periodic maintenance including pumping of the septic tank once every three to five years and
periodic replacement of the leach field. A properly designed, installed and maintained leach field will require
replacement once every 15 to 30 years
Flushing yeast or buttermilk into the septic tank will eliminate the need for pumping.
This organic material does not help or hinder the operation of a septic system which is used continuously. However,
the addition of yeast or buttermilk does not cause degradation of non-biodegradable material which accumulate in the
sludge and scum. Therefore, the septic system must still be pumped periodically to prevent solids from clogging the
If the septic system appears to be failing, flush the septic tank with large amounts of water.
Septic system failures are caused by accumulated solids in the septic tank or clogged soil pores. Flushing the septic
tank will cause the solids to be forced into the soil absorption system and may cause irreversible damage to the leach
field. Flushing water into a clogged leach field will prolong the saturation of the soils and prevent oxidation of organic
material in the soil pores
Weekly use of commercially available lye products will “clean out” plumbing and the septic tank.
The regular use of lye products will destroy the anaerobic bacteria which digest solids in the septic tank. Therefore,
the septic tank will require pumping several times each year to prevent solids from flowing into the leach field.
My septic system is healthy because the grass is bright green over the leach lines.
A bright green leach field area on the surface could be a sign that the effluent is not percolating through the
soil. Look for clear signs of failure, such as standing effluent above the leach lines, or marshy areas