United States
Environmental
Protection Agency
Region 9 Ground Water
Office (WTR-9)
EPA909-F-99-002
JULY 1999
DO NOT USE
CHEMICALS WHICH
HARM SEPTIC
SYSTEMS
Formaldehyde: active
ingredient in some
deodorizers, also called
Formalin. Formaldehyde
is an EPA-recognized
probable carcinogen (i.e.,
causes cancer).
Para-dichlorobenzene:
Known carcinogen and
drinking water
contaminant. Common
ingredient in mothballs,
urinal cakes and bowl
fresheners.
OTHER CHEMICALS TO
BEWARE OF INCLUDE
heavy metals (such as
Zinc), benzene, toluene,
xylene, ethylene glycol
(anti-freeze), methylene
chloride, 1,1,1-
trichloroethane (TCA),
trichlorethylene (TCE) and
perchloroethylene (PCE).
Strong acids and bases,
such as sulfuric acid or
caustic soda, can destroy
biological activity and
damage tanks and pipes.
A healthy, well-
maintained and
appropriately sized septic
tank will generally require
less pumping over its
service life, saving time
and money.
ALERT FOR RV, BOAT AND MOBILE HOME
OWNERS AND PARK OPERATORS
ABOUT SAFE WASTEWATER DISPOSAL
If you spend any time in a recreational vehicle (RV) or boat, you probably know of the
problem of odors from sewage holding tanks. There are a number of commercial
products available to control those odors. Some of those products contain chemicals
which may pollute water resources. If you use those chemicals and then empty your
holding tank into a septic system (or other onsite wastewater treatment system) or
dispose of holding tank waste illegally, you may be creating health and environmental
hazards. These chemicals and their by-products may pass through onsite wastewater
treatment systems, flowing to soil, ground water, and possibly nearby surface waters.
They may also corrode treatment system parts, creating a safety hazard.
How septic systems work. A typical septic system contains two major components:
a septic tank and an absorption field, also known as a drainfield or leachfield. These
systems use natural processes to treat wastewater onsite, as opposed to offsite at a
municipal wastewater treatment plant. The purpose of the septic tank is to separate
solids from the liquid waste, and to promote partial breakdown of contaminants by
microorganisms (bacteria) naturally present in wastewater. The leachfield also treats
the wastewater through physical, biological and chemical processes in the soil.
Mixing chemicals with waste in sewage holding tanks or septic
systems may produce toxic fumes, corrode pipelines and tanks, and
pollute soil and ground water when discharged.
When chemicals, such as formaldehyde, are added to septic systems, they can cause
bacteria in the system to die. When this happens, the septic system cannot treat waste
adequately. Solids that are allowed to pass from the septic tank, due to inadequate or
incomplete treatment, may clog the leachfield. Furthermore, clogged systems may send
inadequately or incompletely treated sewage to the surface, threatening the health of
people or pets who come into contact with it. Or it may percolate to ground water, where
the chemicals and untreated wastewater
could contaminate nearby drinking water
wells, rivers and streams. Please read
labels carefullyto identify any hazardous
ingredients.
The restoration of contaminated ground
water is extremely costly and can take
years. To prevent problems, RV and mo-
bile home parks, as well as dump station
operators, may take measures to control
hazardous chemical disposal into their
waste treatment systems. If they do not,
and their system causes contamination,
they may be forced to close the dump
station or the park until the problem can
be corrected.
' NATIONAL SMALL FLOWS CLEARINGHOUSE
-------
REPORT SEWAGE SPILLS
and other health hazards to the local
health department.
Keep People and Pets Away!
PARK OPERATORS:
The United States Department of Health, Education and
Welfare said in 1957 that"... there are no known chemicals,
yeasts, bacteria, enzymes or other substances capable of
eliminating or reducing the solids
and scum in a septic tank" and
according to EPA, this is still
true. No products have been
verified by EPA to eliminate the
need for routine maintenance,
and some may actually
accelerate system failure by
allowing solids to clog the
dispersal system; while the
products may claim to "remove"
sludge, they may just "move"
sludge. Tanks should be
checked routinely (see photo)
for solids and scum buildup.
Sludge Removal (pumpouts) may be needed more often for
RV, Mobile Home and Boat waste systems than for single-
family septic systems, especially if your tanks are undersized
and/or your residents are conservative with water. Oversizing
your tanks, or adding additional tanks, may allow greater
waste stabilization. Consult a wastewater professional.
diapers, cat litter,
cigarette filters, coffee
grounds, grease, etc.
X«//«v
household chemicals,
gasoline, motor oil,
pesticides, antifreeze,
paint, etc.
RVers CAN HELP...
Here's How:
- Minimize your need of
holding tank deodorizers
by using rest stop
facilities when you can.
- If you must use a
holding tank deodorizer,
read the label carefully.
Biodegradable (enzyme
and citrus-based)
products are available.
Whichever product you
choose, follow label directions and add no more
than recommended amounts.
- Some products that claim to be flushable, such as
some types of cat litter, may clog hoses and septic
tanks; use toilets for waste and toilet paper only.
- Ask questions of your park manager about drinking
water and wastewater management. Sanitation costs
can be minimal, but not free.
- Educate other RVers. Don't be shy about health.
FREE HOTLINES!
Septic System Care: The National Small Flows Clearinghouse, (800) 624-8301, EST, or www.nsfc.wvu.edu
The Safe Drinking Water Act Hotline, US EPA: (800) 426-4791, EST, or www.epa.gov/ogwdw
U.S. EPA, Region 9, WTR-9
Ground Water Office
75 Hawthorne Street
San Francisco, CA 94105-3109
OFFICIAL BUSINESS - PENALTY FOR PRIVATE USE $300
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