SEPTIC SYSTEM CARE & MAINTENANCE
Why Maintain Your System?
There are three reasons why septic system maintenance is important to you and
your community. The first is money. The minimal cost and effort required to
maintain your system can save you or delay future expenditures that could total
up to $2,000 to $10,000 or more for a replacement system. The second and most
important reason is the health of your family and community. Inadequately
treated wastewater can pose significant human health risks and can contaminate
wells, groundwater and surface water resources. The third reason to maintain
your system is to prevent the decline of property values in your community. To
fully appreciate the value of maintenance, however, it is important to first
understand how your system works.
How Your System Works
Home septic systems consist of two principle components: a septic tank where
solid waste is stored and an absorption area where wastewater is treated.
Bathroom, kitchen and laundry waste drains through a large pipe (house sewer)
into your septic tank where it separates out into three layers:
Solids settle to the bottom and, through the action of anaerobic bacteria,
decompose to form a bottom sludge.
Insoluble greases and oils, which are lighter than water, form a floating
surface layer of scum.
The wastewater that remains after solids and scum have separated out forms
a middle layer.
The anaerobic decomposition that occurs in the septic tank is very incomplete.
Septic tanks must be routinely pumped (usually every 3 to 5 years) to
remove the accumulation of bottom sludge and surface scum, Fortunately however,
home septic systems are designed to treat the separated wastewater much more
thoroughly beyond the septic tank, your septic system consists of a delivery
means for distributing wastewater beneath the ground surface where it will
undergo further decomposition through the action of aerobic bacteria present in
Wastewater leaves your septic tank through an outlet surrounded by scum and gas
baffles. These baffles help ensure that wastewater flowing to the absorption
area is relatively free of scum and solids which could seriously shorten the
working life of your system by clogging leach lines and blocking trench walls.
A tool equipped with a filter at the outlet is another extremely effective
means of preventing scum and solids from leaving your septic tank.
From the septic, wastewater flows through an effluent line to the distribution
box. This box distributes wastewater through header pipes to perforated leach
lines set in absorption trenches of stone age aggregate. New, "gravel-less"
systems offer an alternative to trenches filled with stone. These systems
replace conventional perforated leach line either with leaching chambers or
with pipe wrapped in geotextile.
In the typical absorption field, each length of leach line or leaching chamber
is set in its own individual trench. This results in an absorption field
consisting of a series of parallel trenches that are about 18" to 30" deep.
Because the aerobic bacteria that decompose waste thrive mostly in this upper
area of the soil, this type of system provides the most thorough treatment of
wastewater. It also helps protect groundwater from possible contamination by
affording the greatest possible separation distance between trench bottom and
the water table. Occasionally, however, space limitations may require different
approaches. If soil and groundwater conditions permit, seepage pits are an
option. Another alternative is a stone bed where all the leach line is laid in
a single, wide trench with stone aggregate.
All absorption areas, regardless of type, are subject to the same aging
processes. In every case, a biomat forms on the trench walls. Initially this
biomat aids wastewater treatment by straining out pathogenic bacteria. But, as
more bacteria and waste add to the biomat, the trench walls become more
impervious to the passage of wastewater. Siltation and soil compaction can
further slow the absorption rate. Eventually, wastewater might either back up
into the house plumbing or seep out onto the ground surface.
With constant usage, this aging process is inevitable. Usually, however,
moderate maintenance can prevent premature failure.