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Aerobic and Anaerobic Septic System Costs

Last Updated on December 29, 2023
Written by CPA Alec Pow | Content Reviewed by Certified CFA CFA Alexander Popinker

On-site septic systems are the common form of wastewater treatment in rural and suburban areas where homes are not connected to a central sewage system. Traditionally, most septic systems used in the United States have been anaerobic. More recently, aerobic septic systems have begun to be installed in many homes. There are advantages and disadvantages associated with both types of systems.

The basic difference between aerobic and anaerobic septic systems is the presence or absence of oxygen. Traditional anaerobic septic systems are operated in underground tanks and in the relative absence of oxygen. This means that bacterial colonies that break down wastewater must be able to live without oxygen. Although most aerobic septic tanks are also located underground. They depend on a mechanism called an “aerator” to inject oxygen into the tank from the outside.

The anaerobic septic systems are simpler and cost anywhere between $2,100 and $5,100, while the aerobic septic systems are more complicated and cost anywhere between $10,500 and $20,500.

In the table below you will find the average costs for the septic system installation in different states from America.

City or State Zip Code Average Price Paid
New York City 10001 $6,275
Boston, MA 02108 $7,787
Philadelphia, PA 19019 $11,878
Massachusetts Statewide $6,487
New Hampshire Statewide $9,325
North Carolina Statewide $3,511

How much does cost an aerobic septic system cost?

The cost of an aerobic septic system will depend on some factors such as the place where you are living, the soil conditions, and the size of the system. When estimating the costs of such a system you should consider some expenses such as:

  • the permits and the site evaluation which would be anywhere between $210 and $420;
  • the aerobic septic system that is anywhere between $10,500 and $20,500;
  • the costs with the inspection and pumping which are around $210 (this work has to be done every one to three years by a professional);
  • the costs of the timer replacements that have to be done from time to time and would be around $110;
  • the costs of the motor, which also has to be replaced at some point and would be anywhere between $550 and $620.

How much does an anaerobic septic system cost?

The same as with the anaerobic system, the price of the anaerobic septic system depends on the location, the size of the system, and the soil conditions. Also, you have to consider the following expenses:

  • permits required to install the system which will cost anywhere between $270 and $1,100, depending on the place where you are living;
  • the cost of the anaerobic system which would be anywhere between $2,100 and $5,100; though there are areas where the material costs and the labor rates are so high that the price of an anaerobic septic system would be anywhere between $4,100 and $15,500;
  • depending on the size of the tank, the price of the septic tank would be anywhere between $550 and $1,900;
  • the cost of the piping and the related materials will be around $110 to $220;
  • the costs with the yearly pumping which are anywhere between $210 and $420;
  • the cost of the inspection that has to be done every one to three years and will be anywhere between $210 and $650.

What are the labor costs to install a septic system?

You may be surprised, but the costs to install a septic system are in most cases as high as the system itself, if not higher. The average cost of a septic system installation will be anywhere between $1,550 and $4,500.

You might also like our articles about the cost to replace a toilet wax ring, to install a toilet or the costs of the Roto-Rooter plumbing services.

You may want to avoid these costs and try to install this system yourself, but this is not recommended. You should hire a professional to install the septic system properly. If this job is not done right you may be faced with great damage and costly repairs due to leaking and water pollution.

When looking for a professional to hire do not pay attention only to the prices, but also the reputation, the quality of work, and experience.

The advantages and disadvantages of the aerobic septic systems

Anaerobic Septic SystemAerobic treatment is a biological wastewater treatment process that uses an oxygen-rich environment.


Because aerobic bacteria are able to treat wastewater more thoroughly, aerobic septic systems usually require smaller runoff than anaerobic septic systems. Therefore, aerobic systems are a space-saving choice and may be the best choice for homeowners who have little space or soil that is not optimal for runoff.


Aerobic wastewater treatment requires energy. Therefore, they are less energy-efficient and also increase your monthly electricity bill.

Aerobic septic systems are more expensive to maintain than anaerobic septic systems. Because aerobic septic systems contain working mechanical parts, such as air vents, they are more susceptible to mechanical failure and usually require more routine maintenance.

Colonies of aerobic bacteria are also better at breaking down human waste than anaerobic bacteria. However, aerobic bacteria are less able to break down inorganic solids, so aerobic systems can become clogged more easily.

The advantages and disadvantages of the anaerobic septic systems

Anaerobic wastewater treatment is a biological treatment process in which organisms, especially bacteria, decompose organic matter into wastewater in an oxygen-deprived environment. Anaerobic digestion is a well-known process for treating anaerobic wastewater. Degradation of organic material is anaerobic. For efficient anaerobic digestion of organic materials, air entering the anaerobic tanks is prevented.


Anaerobic wastewater treatment is an energy-efficient process.

During anaerobic digestion, methane and carbon dioxide are produced. Methane is considered a biogas. Therefore, the anaerobic digestion process can be used to produce biogas that can be used as electricity.


While most aerobic septic systems contain an alarm that warns the homeowner of any problems with the system, many anaerobic septic systems do not. This is a major drawback, as undetected septic problems can get worse quickly, and extensive underground septic repairs can be very costly. Septic systems can even fail completely and might need to be replaced.

How to choose a septic system?

If you have difficulties in choosing the right septic system for you, then you should ask yourself some questions such as:

What is the size of my lot? Aerobic systems are recommended for small surfaces.

How much money can I spend on a septic system? If you are on a budget then you should choose the traditional anaerobic septic system.

What are the local laws? It is forbidden to install an aerobic septic system in my town or city? If the answer is yes then you can forget about installing your own septic system.

Can I stick to a maintenance schedule? Aerobic systems need more attention compared to anaerobic systems and if you forget about periodically inspecting these then you will face greater costs.

How important is the environmental impact for you? If you care about the environment then you should choose the aerobic system because it produces cleaner water.

How to choose a contractor

There are many septic contractors, but it may be hard for you to choose the right one. So, before hiring a professional you should consider some aspects such as:

  • make sure the company you are going to hire is insured, licensed, and bonded;
  • search for more price offers and compare the costs;
  • ask your friends, family, and neighbors for references.
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