AMC Septic Design & Testing Services LLC - Providing Design & Testing Services to Chicagoland for 24 Years!
In order to assist with your project, we have compiled a list of the most frequently asked questions so that you are better able to make informed decisions that suit your individual needs.  To make your research as easy as possible, the answers to the following questions will avoid overly technical wording and will seek to provide simple, concise answers in plain, everyday language.  As always, feel free to contact us if you should need additional information.  Consultations are always free!
Why should I use AMC Septic Design Services?
There are several good, local engineering firms that are able to provide a quality product.  We like to go that extra mile to make sure your overall experience with us is so memorable that you would recommend our services to others.  We have worked very hard over the years to build a fine reputation and certainly wish to preserve this!  In addition to a finely prepared engineering product and knowledge of local ordinances, you will be impressed by the fine level of personal care you will experience.  You will be attended to, if not immediately, always by the end of the business day.  And as always, we are available to spend time with you to answer all of your questions and assist you through the entire process.
What is a "conventional" septic system?
The word "conventional" is often used to describe the most basic of septic system types consisting of a septic tank and a septic field.  The septic tank, usually constructed of concrete is used to separate the liquid from the solid waste.  The solid waste is retained in the septic tank where it breaks down naturally while the liquid waste (called effluent) is allowed to pass through to a simple septic field where it seeps down into the soil.  The most common type of field consists of simple gravel trenches with a perforated pipe running the length of the trench.  The trench is covered with grass or native growth and so is not seen.

What is an "aerobic" septic system?
An aerobic treatment plant or "aerator" can be added to any type of septic system including conventional.  Simply put, this unit adds oxygen, converting the system from "anaerobic" to "aerobic".  Since many more microbes can be sustained in an environment in which an oxygen source is provided, the waste is broken down more quickly and the water begins to be recycled at a much faster rate.   An illustration of this concept is the addition of aeration to an aquarium.  The additional air sustains more aquatic life in the tank and assists in keeping the water cleaner than it might be without the aeration. 
Contrary to popular belief however, although this septic waste is much less of a health hazard than untreated waste, this effluent must still be discharged to some type of underground disposal septic field.  Some jurisdictions, though, may allow for the septic field to be reduced in size due to the more efficient nature of an aerobic system.
What is a "mound" septic system?
A "mound" system has a septic tank and possibly an aerobic unit much the same as other types of systems.  The difference is that instead of the septic disposal field being located below ground, it is located ABOVE ground.  In some areas where poor soil conditions are found and/or an unusually high groundwater table is found, it is necessary to elevate the disposal system to a certain height in order to protect the water table as well as the surrounding environment.  The result is a "mounded" area which is covered with grass or native vegetation.  The most common types of mound systems are the "Wisconsin Mound" or "Raised Filter Bed" mound.
What is a percolation test?
In simple terms, a percolation test or "perc" test is a measure of a soil's ability to absorb water.  A series of test holes from 18 inches to 36 inches in depth are dug with a post hole digger and the holes are filled with water for most of the first day to simulate saturated conditions.  On the second day the actual test is conducted for a period of four to six hours.  The test holes are filled with a prescribed amount of water and each hour the level of water drop is measured.  The calculated result shows the absorption capability of the tested area and is used to properly size the septic system.

What is a septic soil suitability report?
A soil suitability report is a different method of testing the soil for septic suitability.  Some jurisdictions require this method of testing instead of a percolation test or they may allow your choice of either.  A septic soil suitability report is conducted by a licensed soil scientist who takes a series of core samples of the soil by drilling into the area of the proposed septic system.  The core samples are then analyzed according to laboratory methods to determine several different features of the sampled soil.  A report is then prepared that the septic designer will use to properly design and size the septic system.
How often should I have my septic tank pumped out?
In general, an average residential septic tank should be pumped at least every two to three years.  Some circumstances such as a very old system, a very undersized system or an exceptionally large number of people living in the residence may require more frequent pumping.  Conversely, a system that has a low usage or one that serves one or two persons may require pumping less often.  Commercial systems can vary widely in their needs due to many different variables.  If you are not sure about the servicing requirements of your septic system, give us a call and we would be happy to discuss your individual or unique circumstances.
How often should my aerator be serviced?
Most agencies now require your aerobic unit to be serviced once or twice per year.  They may also require you to obtain a service contract agreement with the firm of your choice in order to ensure the timely servicing of the unit.  Contact your local health department in order to ascertain the exact requirements for your area.  Some areas are now in the process of revising the details of their ordinances with regard to aerobic units.  We will update this page as new information becomes available.

Do septic additives really work?
In general we do not recommend the use of septic system additives such as you may have seen advertised on TV.  Chemical additives can destroy the microbial colonies living in the system which are necessary for proper waste breakdown.  Biological additives may not do any harm, but generally have no long-term benefit.  If a large quantity of chemicals has recently been put down the drain, a biological additive can help to restore the living colonies.  One use, though, should be sufficient.  Household domestic waste already contains all of the biological "additives" that a septic system would need to maintain a health colony.  A study cited by Cornell University found that septic additives did not enhance the operation of a septic system.  See "Water Quality Information for Consumers" on the Cornell website.
Is it true that if I chose an aerobic unit I do not need a septic field?
This is false.  Although the septic waste water has been treated by the aerobic unit, it still needs to be properly disposed of.  Some type of a seepage system would be required in order to accomplish this.

What kind of trees or bushes can I plant in the septic field area?
For your convenience, click this link to the handout "Trees and Septics" provided by the Morton Arboretum in Lisle, Illinois.  This information, though not exhaustive, provides a good reference guide of invasive and non-invasive tree and shrub species applicable to our Midwestern zone 5a climate.
Can I build anything over my septic system?
Buildings, decks, patios, roads, driveways, swimming pools, and most anything else may not be constructed over a septic tank or a septic field.  In some areas, a deck may be constructed over a septic tank (but not the septic field) as long as an access cover is built into the deck for access in servicing the tank.
Can a septic system be installed in winter?
Yes!  As long as the frost level is not too deep to prohibit digging and as long as the soil is not too wet, septic construction can be done at any time of the year.  Some frost is actually helpful as it will support the weight of the machinery and protect the soil from damage due to compaction.
How can I find tips on maintaining my septic system?
The U.S. Environmental Protection Agency has a helpful handout containing useful information on the operating and maintenance of residential septic systems.  Go to"A Homeowner's Guide to Septic Systems"  to obtain this handout for yourself.
How can I avoid overloading my septic system?
You can avoid overloading your septic system by practicing water conservation.  Use low-flush toilets, water saving shower heads, high efficiency clothing washers and water saving dishwashers.  You can also extend the life of your septic system by taking shorter showers, not leaving faucets running unnecessarily, and spacing out loads of laundry over the course of the week rather than all at one time.
What types of items should not be disposed of into the septic system?
Avoid putting non-biodegradable or slowly degradable items into your septic system.  Such items will collect and build up in the tank requiring you to have the tank pumped more often.  Such items include anything plastic, diapers, feminine products, prophylactics, sanitary wipes, cigarette butts, and paper towels.  Dispose of cooking oils and greases as well as coffee grounds into the trash rather than down the drain.  These items can clog the system over time.  Also use kitchen garbage disposals sparingly.  This finely chopped waste can pass through the tank baffle and accumulate in  the septic field, reducing the life of the system.


How can I get the best use of my septic system and still be "Green"?
Check out "Green Tips"on the Illinois Environmental Protection Agency web page.  This site provides much information as to the various ways we can protect our environment including the proper use and maintenance of septic systems.
Are there some types of waste water that should not go into the septic system?
The life of the septic system can be extended by disconnecting any unnecessary sources of waste water that do not need to be discharged to the septic.  All "clear-water" discharges such as water softener, sump pump, and gutter downspout discharges should not go into the septic sytem.  These should be disposed of separately according to the method required by your local governing agency.  We would be happy to help you find out what your local ordinances are.
What chemicals will harm my septic system?
Chemicals such as paint, pesticides, fertilizers, motor oil, or harsh cleaning chemicals should not be put into the septic system.  These harsh chemicals can not only kill the biologic activity in the system, but can also  contaminate groundwater and soil.  Try using "septic friendly" cleaning products which do not contain harsh chemicals.  You can refer to "Managing Septic Systems to Prevent Contamination of Drinking Water" on the U.S. Environmental Protection Agency website for more helpful information.
What if I have more questions?
Give us a call!  We are here to help you.   You may consult us with any questions or concerns you may have.  As always, this service is free of charge!
We hope that these answers and suggestions have been helpful!  Although this information should not be understood as letter of law, these are professional opinions based upon our years of experience and education in this field.  If you would like more detailed or technical information, please feel free to give us a call at: 847.722.5271.