Antibacterial Products in Septic Systems
Extension, College of Agriculture & Life Sciences, The University of Arizona
Kitt Farrell-Poe, Water Resources Specialist
The University of Arizona Cooperative Extension Septic System Owners
To improve septic system performance:
- Do not use "every flush" toilet bowl cleaners.
- Reduce the need to use drain cleaners by minimizing the amount of
hair, grease, and food particles that go down the drain.
- Reduce use of cleaners by doing more scrubbing with less cleanser.
- Use the minimum amount of soap, detergent, and bleach necessary to
do the job. Frequent use of detergents with bleach additives is considered
excessive amounts of bleach.
- Choose products that meet your needs safely. When you are shopping,
always read the instructions on the product labels. Labels provide information
on a products content, as well as instruction on how to use it
safely. Check to see if the product contains ingredients that, when
used properly, can harm people or the environment.
- Use minimal amounts of mild cleaners, as needed only.
- Divert chlorine-treated water from swimming pools and hot-tubs outside
of the septic system.
- Dispose of all solvents, paints, antifreeze, pesticides (insecticides,
fungicides, herbicides, slug bait, moth balls, wood preservatives, and
flea and roach powders, to name a few), and other toxic chemicals through
local recycling and hazardous waste channels.
- Do not flush unwanted prescription or over-the-counter medications
down the toilet.
An onsite sewage treatment system or "septic system" is effective
way to safely recycle household wastewater back into the natural environment.
As a homeowner or business person with a septic system, you are in the
wastewater treatment business.
A septic system with a properly functioning, soil treatment-based, leach
field should reduce bacterial and pathogen levels to an acceptable level,
if not completely. Potential organic and inorganic nutrient pollutants,
those commonly found present in septic wastewater effluent, should also
be reduced or eliminated. The key to effective treatment is proper design,
system installation, responsible operation, and periodic maintenance.
Note: "Operation" refers to everything we do or put into the
To achieve proper treatment, a septic system is very dependent on millions
of naturally occurring bacteria throughout the system. Daily, we add many
beneficial bacteria to our septic systems; bacteria typically found in
wastewater, our bodies, and other waste materials we dispose of via our
septic system. Two very important types of septic system bacteria are
anaerobic (do not require oxygen) and aerobic (require oxygen). Anaerobic
bacteria decompose organic materials inside the septic tank. Aerobic bacteria,
in the leach field soils, destroy disease-causing pathogens and finish
the breakdown of molecular waste products. Simply stated, we normally
and naturally add more than enough of the "right kind" of bacteria
to our septic systems; there is no need or reason to use expensive, unnecessary
The use of "antibacterial," "disinfectant," or "sanitizing"
products in the home can and do destroy both good and bad bacteria in
septic treatment systems. "Normal usage" (according to directions)
of these products will destroy some beneficial bacteria. Fortunately,
the normal bacteria population within the septic system is sufficient
and adequate to quickly recover. Significant treatment problems, with
conservative use, should not occur. Excessive use of these products in
the home can cause significant and even total destruction of the bacteria
population. Normally, the use of any single product or single application
will not cause major problems.
However, the accumulative affect of using too many such products and
excessive application may cause serious problems and damage to the septic
More research is needed to determine what is excessive and which products
are more or less harmful to systems. Increasingly, many products are being
marketed as "anti-bacterial." Consumers and onsite system professionals
working to diagnose treatment system problems have many questions about
individual products. Typical questions being asked are: "How antibacterial
is antibacterial?" and "Which products are better or worse than
others?" Anecdotally, several professionals have reported problems
with low or no bacterial activity in systems. Upon removal of such "antibacterial"products
from the home, beneficial bacterial activity returns and the desired treatment
functions resume. "Antibacterial" products affect all treatment
systems, some more than others.
Special attention is being paid to new "alternative" septic
treatment technologies being introduced into the onsite industry. It appears
that some alternative systems may be more affected by "antibacterial"
products than other systems. Additional and more conclusive research is
What are common "antibacterial," "disinfectant,"
and "sanitizing" products found and used in homes and businesses
that might affect your septic system? The list of products include: "antibacterial"
hand soaps; sink/counter top cleaners; tub, tile, and shower cleaners;
drain cleaners; toilet bowl cleaners; laundry bleach products; and many
industrial strength cleaners used commercially. Antibiotic drugs (prescribed
medicines) should also be included. These are products that are found
in nearly all homes. Such medications often carry a "safe for septic
systems" statement printed on the label. A relevant question for
using these products and medications may be "how safe?" All
of these practices work toward preventing the loss of beneficial bacteria
throughout the system. Bacterial additives (enzymes, starters) are not
necessary, may not compensate for excessive use of antibacterial products,
and are costly.
It might be that, in an effort to be "super clean" and protective
of our familys health through the use of antibacterial products
in our homes, we might be compromising our health in another way - by
damaging our onsite sewage treatment system!
There is more information on household septic systems at the University
of Arizona Extension publications web page (http://ag.arizona.edu/pubs).
This fact sheet was adapted from the Anti-Bacterial Products
in Septic Systems, by Ken Olson, University of Minnesota Extension
news release, located at http://septic.coafes.umn.edu/Homeowner/index.html.
The University of Arizona is an Equal Opportunity/Affirmative
Action Employer. Any products, services, or organizations that are mentioned,
shown, or indirectly implied in this publication do not imply endorsement
by the University of Arizona.
Document located http://cals.arizona.edu/pubs/water/az1258.html
Published September 2001
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