Stormwater
Quality Management Committee
Clark County Regional Flood Control District
600 S. Grand Central Pkwy. Las Vegas, NV 89106 |
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Private
Sewage Disposal Systems - Septic Tanks
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Best
Management Practices for:
Home
Owners and Business Owners
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Clark
County is responsible for making sure that water bodies affected
by activities of residents and businesses within the Las Vegas
Valley, are pollution free.
Sample tests of run-off water taken regularly in the Las Vegas
Wash outlet, too often, result in high levels of bacterial content
that exceed safe water contact recreation, especially during
rainy weather.
One potential source of bacteria in the watershed are malfunctioning
sewage disposal systems. Septic tank failures have been documented
on private properties in the Las Vegas area.
The following information is a reminder on how to maintain a
private sewage disposal system —and keep our environment clean.
Septic System Description
A septic tank is the first stage of a private sewage disposal
system. The septic tank is a watertight tank below ground and
is usually made of concrete and sometimes of fiberglass or steel.
It usually has one or two access ports a few inches below ground.
The tank receives household wastewater through an inlet pipe
near the top of one side, settles out larger material to the
bottom, breaks down waste material with in situ bacteria, and
delivers the partially treated wastewater out another pipe on
the other side to the disposal field via a distribution box.
A disposal field is the second stage of the private sewage disposal
system and completes the final breakdown of the wastewater with
organisms in the soil.
The disposal field consists of narrow trenches filled with gravel
and perforated pipes that distribute the wastewater to the field.
With proper maintenance, a well designed system should last
indefinitely; however, disposal field soils will normally clog
if forced to handle the large particles that should settle out
in the bottom of the septic tank.
Routine pumping of the septic tank is imperative to avoid thousands
of dollars in replacement costs of the disposal field.
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Phosphate
Detergent Use
Eliminating
phosphate containing detergent can reduce phosphorus loads
to septic systems by 40 to 50 percent. Certain soil conditions
combined with close proximity to sensitive surface waters
can result in increased phosphorus pollutant loading in
the stormwater.
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Chemical
Additive Use
Organic
solvents are advertised for use as septic system cleaners
and sometimes as substitutes for sludge pumping, however
there is little evidence that such cleaners perform any
of the advertised functions and can instead exterminate
useful microbes, resulting in increased discharge of pollutants.
In addition, the chemicals themselves, halogenated and
aromatic hydrocarbons, can easily contaminate storm waters
and some common cleaner constituents are listed as environmental
pollutants. Restrictions on the use of these additives
can preclude further exacerbation of poor system function.
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Garbage
Disposal Use
Eliminating
the use of garbage disposals can significantly reduce
the loading of suspended solids, nutrients, and BOD to
septic systems, as well as decreasing the buildup of solids
in septic tanks, thus reducing pumping frequency.
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Regular
Inspection and Maintenance
Septic
tanks require regular inspection and maintenance. Pumping
should be done to remove accumulating sludge approximately
every 3 to 5 years. The frequency can vary depending on
tank size, family size and garbage disposal use. Failure
to remove sludge periodically will result in reduced tank
settling capacity and eventual overloading of the soil
absorption system, which is more expensive to remedy.
Maintenance can be required through contracts, operating
permits, and local ordinances/utility management.
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