The ABCs of Septic Systems: Uncovering the Different Types and How They Work

Chances are, if you are not someone who works with servicing sewers and septic tanks, you won’t know much about septic systems. Having said that, there is a benefit to understanding the types of septic systems as a homeowner, business owner, and so on. Buying a house with a faulty septic is one of the worst problems you can have. 

That’s why here we can look at how a septic system works and what makes each type different from another. Not all septic systems can function properly in each home or building scenario.

The two primary types of septic systems are conventional and chamber systems. One is a more traditional approach that has been around for decades while the other offers alternative solutions such as eco-friendly options. 

SystemCostBest For
Conventional$10,000 – $25,000Traditional domestic home
Chamber$4,000 – $10,000Vacation homes/less occupied areas
Drip$500 – $14,000Sloped areas
Aerobic$15,000 – $20,000Those who want to treat waste more naturally and budget isn’t a factor
Mound$10,000 – $20,000When public sewage setup isn’t an option and the use of gravity is available (slopes)
Recirculation Sand Filter$7,000 – $20,000Those looking for a modern approach to a septic tank
Evapotranspiration$10,000+Good for areas without rich soil (heavy clay soil/gravel)
Constructed Wetland$7,500 – $15,000Great for agricultural environments
Cluster$5,000 – $8,000Housing developments
Aerated$10,000 – $20,000Industrial or municipal buildings

Knowing what the best fit is solves multiple headaches down the road. 

How A Septic System Works

Septic systems are (mostly) underground chambers that can be made of several different materials to store and decompose waste. They can be made of fiberglass, concrete, or even plastic. Septic systems have a few different types, but they all serve as an onsite sewage system instead of running through town or city piping.  

How Septic Tank Works
How Septic Tank Works

The goal is for the organic matter to break down in the chamber while separating the fluids. The chamber causes a bacterial reaction that decomposes the waste into the fluid. The fluid is also known as effluent. As the fluid becomes drainable, they go to drain fields or an alternative chamber. 

They can also be referred to as leach fields. Some other systems have a slightly different approach, such as using gravity or pumps to get the fluids to move into drain fields that may consist of sawdust or wetlands.  

Best Septic Tank Materials

Choosing which type of septic system to install on your property is only one of many choices you’ll need to make. Several types of materials are used to make septic tanks, though the most common are precast concrete and high-density plastic.

Other common materials include fiberglass, fiber-reinforced plastic, and concrete blocks. Let’s take a look at some of the pros and cons of each of these materials, as well as how much you can expect to spend. Different materials will have different prices, and some are preferred over others. Let’s talk about them.


These are usually some of the biggest septic tanks because of the materials. They are typically a casted mold and placed inside the area made for it. Concrete septic tanks are available in two different molds, singular and all-or-one systems. The average cost is between $2000-$7,500. 

Fiber-Reinforced Plastic 

This is a newer option as it is an environmentally friendly option. The fiber-reinforced plastic helps keep waste in and stops sewage from polluting the environment. It’s also eco-friendly and said to be the replacement for traditional septics. 

High-Density Plastic

High-Density Plastic is used in many materials today because it is so heavy-duty it doesn’t break down. They have become an easier alternative than concrete because they cost less to install and make. They generally cost around $1,200. 

Type of MaterialAdvantagesDisadvantagesPrice for Septic Tank*
Precast ConcreteGreat resistance to buoyancy Extremely durableEasier to customizeWide variety of sizes availableLess strict installment requirementsSubject to corrosionMaterial is very heavy and difficult to move, so installation may be difficult in areas with limited access$1,500
High-Density PlasticEasy InstallationNot subject to rust or corrosionLess chance of leaksLess expensive optionLight-weight material is more prone to floating above the ground in areas with a high water tableNot usually available for larger capacitiesLimited depth they can be buried$2,500
FiberglassLightweight material makes for easy installationUnlikely to rust or experience corrosionHarder for roots to penetrate this materialCan float to the surface of the ground if installed incorrectly or in an area with a high water tableMore strict installation requirements$1,600
Fiber-Reinforced PlasticLightweight material makes for easy installationUnlikely to rust or experience corrosionAvailable in larger capacitiesAble to be buried very deeplyWon’t bend as easily as plastic tanksStrict installation requires to ensure structural integrityMore likely than other materials to float out of the ground in areas with a high water table$2,000
Concrete BlocksSame advantages as precast concrete septic tanksMore prone to damage and corrosion than precast concreteMay take longer to install than precast concrete$1,500

Conventional Systems

1. Conventional System 

The traditional septic system is the most popular option because it’s easy to install, requires little maintenance, and tends to be more cost-effective. The conventional septic tank system refers to two processes; pump systems and gravity systems.

Both septic systems require a main pipe to lead waste from the home into the septic tank. Each system also requires a drainfield for the dispersion of wastewater. The difference lies in how each system moves the wastewater.

Gravity systems, as the name suggests, use the force of gravity to move wastewater from the home and into the septic tank.

How Conventional System Works
How Conventional System Works

Pump systems use a pump to force the wastewater from the home and into the septic tank.

The conventional septic system does have a few disadvantages. They’re typically harder than other systems to keep clean and often have fewer wastewater treatment options than other systems.

An entire conventional system that is being put in from scratch will cost between $10,000 and $25,000. This includes digging the trenches for the drain field, the piping, and the installment. The size of the house and septic tank plays a big variable in the cost. 

2. Chamber System 

A chamber system technically falls similarly into conventional systems. However, it differs slightly in the way that it decomposes its sewage. The biggest thing to consider is that the chamber system will not go through gravel or a stone drain field like the conventional system. 

The system that this one uses has the fluids go to a different chamber where sand or soil is already placed within the chambers. Cases, where this type of septic is most commonly used are in places where the amount of waste varies greatly throughout the year. A great example of this is a vacation home. 

How Chamber System Works
How Chamber System Works

As mentioned earlier, this is where we may see a gravity septic system be used. As a reminder, this is when the effluent is pushed out into the soil using gravity or, in most cases, downward-sloping piping. While the cost varies, typically, chamber systems cost between $4,000 and $10,000, with everything being installed. 

While these are the more traditional systems, there have been alternative designs made in more recent years that have gained popularity. 

Alternative Systems 

3. Drip Distribution System

The drip distribution system is a very different way of treating effluent in the drainfield. This system comes with more parts than conventional systems. Drip distribution systems require a dose distribution tank, electrical power, and a series of small tubes to function properly.

With this system, effluent is dispersed over a large drainfield slowly and evenly. This allows the microbes in the soil to properly treat the effluent over time and absorb nutrients before the treated wastewater reaches the groundwater.

Drip Distribution System
Drip Distribution System
Photo credits:

A drip distribution system is neat because it releases small portions of wastewater at timed intervals. While this may not be the most pleasant comparison, consider it to be similar to drip coffee. Only minimal wastewater is released when it works with a drip system. 

The benefit to this is that it gives more time for the waste to be treated while also minimizing the risk of untreated waste polluting the surrounding environment.

The system was made for areas that have a harder time making trenches. That’s why you will see drip systems be installed on slopes or areas that are steep to allow for the waste to travel quickly and spread through the soil 

A drip distribution system can cost you more in maintenance and equipment over time. The upfront cost will vary between $4,000-$10,000. For instance, it is common to see them placed in resorts or on golf courses. 

4.  Aerobic Treatment Unit 

Aerobic treatment units are naturally more complex than conventional systems. They are offered in many different designs and rely on oxygen to digest the organic matter. This is opposed to an anaerobic system or known as a conventional system. The process itself is also more natural for treating waste. 

There are four main stages that an ATU uses to do this. The first is the pre-treatment, with a separate tank to separate the waste from the liquids.

How  Aerobic Treatment Unit Works
How Aerobic Treatment Unit Works

Next, the Aeration chamber will force air through a blower or compressor to mix with the wastewater. It starts the process of bacterial growth. Then disinfection occurs with UV light or chlorine. Lastly, the effluent goes to a drain field. 

Aerobic treatment units (ATUs) take the idea of sewage systems and use them on a smaller scale. Waste is broken down in ATUs by injecting oxygen into the treatment tank. The oxygen increases the bacterial level in the treatment tank, which helps encourage the breakdown of waste.

Some ATUs may also have a pretreatment and a final treatment tank for the treatment of effluent. This type of system provides much better treatment for waste than conventional methods and typically requires far less maintenance.

The drawback to installing an ATU is that it is costly. They are one of the more expensive options on the market ranging from $15,000 to $25,000. 

5. Mound Systems 

Mound systems are technically a non-standard septic system option. Mound systems are used where public sewage isn’t an option and uses gravity to move the waste as well.

A mound system is a good option if you live in an area with inadequate soil for a regular drainfield or an area with lots of bedrock. This method erects a large mound of soil/sand to act as the drainfield. Effluent is pumped in small doses to filter down through the mound before dispersing into the original soil.

How Mound Systems Works
How Mound Systems Works
Photo Credits:

The “drain field” is elevated rather than under the ground and uses a dual-chamber system. On average, these cost between $10,000 and $20,000. 

6. Recirculating Sand Filter System

Recirculating sand filter systems are a modern and affordable approach to conventional systems. The effluent gets sprayed or dispersed over a sandbed in this particular situation.

The wastewater gets filled with this sand and then gets treated. When the effluent falls to the bottom layer, that layer gets recirculated to the top of the sand over and over again to break it down. 

How Recirculating Sand Filter System Works
How Recirculating Sand Filter System Works

For these types of septic systems, you can bet on spending anywhere between $7,000 and $20,000. Generally speaking, they are a little cheaper. If an aerobic system is incorporated, the price naturally increases. 

7. Evapotranspiration System 

Evapotranspiration systems are constantly used in situations where groundwater and surface water must be protected at all costs.

Evapotranspiration systems are very unique and different from other septic systems. With this system, effluent never reaches groundwater. Instead, the base of the evapotranspiration system is lined with a watertight material, so the effluent evaporates into the air.

This is a great system for areas with certain environmental and soil conditions. However, you need to be in a warm, arid climate, and the system can fail if you receive too much rain or snow.

How  Evapotranspiration System Works
How Evapotranspiration System Works
Photo Credits:

How it works is that the system uses evapotranspiration. This is the process of the water evaporating from the sand and transpiration from plants. This system is most commonly used in areas with rocky soil and heavy clay soil. 

From some perspective, a three-bedroom house can count on paying $10,000 minimally for this type of system. The price increases if the site conditions become more difficult to work with. 

8. Constructed Wetland System 

Using natural wetlands, this system will have visible water over the surface level. In these scenarios, that area is specifically constructed to treat wastewater and is not used for any other reason. The microorganisms, plants, and surrounding area act as a treatment center to break down the effluent and treat it. There is still a septic tank in this process, but instead, the wetlands act as the drain field. 

How Constructed Wetland System Works
How Constructed Wetland System Works

The general cost for wetland septics is between $7,500 and $15,000, depending on the size. Because of the ample space needed for a wetland space, only certain climates and geographical locations make sense for this type of system. 

9. Cluster / Community System 

Cluster systems are used to treat wastewater from more than one home. Typically, these systems treat a few homes in rural areas. The waste from each dwelling will flow to a nearby and centralized treatment and disposal system.

A cluster or community system acts exactly how it sounds. Each household or building may have its own septic tank, but they all get funneled through small piping to the treatment area or drain field. This costs around $5,000 to $8,000 to be put in. 

10. Aerated Wastewater Treatment System 

Aerated wastewater treatment systems are normally reserved for industrial or municipal buildings. Aeration is a process where microbial growth occurs in the sludge to decompose wastewater. 

The bacteria is often called activated sludge and recirculated to increase microbial growth rate. When aeration is used for industrial purposes, it is common to see the water-fall method with hoses and spray nozzles. 

Sometimes they may use air diffusers but are less common. How the water is actually aerated can be done through several techniques and options. For instance, shallow aeration is best in situations where the surface level of water is shallow. 

It is not a one-size-fits-all system. The range for installing a system like this falls between $10,000 and $20,000. The price will depend on which type of aeration you use, the property type, and so on. 

Never Flush Chemicals 

No matter what type of septic system you have listed above, it is crucial to understand that you should never flush any chemicals down the toilet drain. There are a few reasons for this, but the most important one is that you can kill the microbial and bacteria that help treat the wastewater. 

Chemicals can also eat into your system over time and cause issues in the piping or septic tank. These are common household items such as paint thinners, cleaning products that unclog drains, floor cleaning supplies, and so on.  

Why You Should Keep Your Tank Clean

Keeping chemicals out of your tank is a part of keeping the tank clean. But it takes much more effort than just that to truly have a clean tank. There are different processes, such as naturally cleaning the tank as well as pumping the tank. At different points in time, you will do both. 

  1. Pumping occurs periodically. The exact time depends on the household size. But you can expect to have it done every 3-4 years, costing around $400. This is when a professional comes and uses a pump to vacuum out the sludge, water, and oils. This technically does not clean the septic tank but just empties out the contents. There will still be a level of waste in the tank.  
  1. Cleaning the tank, however, gets the compacted waste that sticks to the bottom level of the tank. Cleaning the tank is much less frequent, especially if you are properly pumping it to take good care of it. The longer things sit, the harder it is to clean. 

Septic tanks and systems should have a good life expectancy and last a few decades if they are of good quality. Taking care of them, however, can be the difference maker in their lifespan. Hiring out regular cleaning is the key to keeping a septic tank as healthy as possible. 

How Frequently Does Your Tank Need To Be Cleaned? 

Monitoring your septic tank is important. The easiest way to see if something isn’t working right is if your toilets are always clogged or getting backed up. In this case, it is good to call a professional because they may need to take a look at the entire system. It’s recommended that septic tank pumping should occur about every 3-4 years for conventional systems. 

If you have an alternative system, it is recommended to have it inspected yearly to ensure it’s working correctly. This is because there are usually more pumps and mechanical parts that can cause an issue if they malfunction. 

Call a Professional for Inquiries

Septic tanks are something that requires professional help. When looking to install a new septic system, it is best to talk to a professional that can address your property type and what will fit best. Certain areas will have different restrictions which a professional can shed light on. That way, you make the right investment in the right septic system. 

A buyer shouldn’t stress as much about what type will be perfect for them because the experts can help guide you through the process. Some options may simply be unavailable to your area due to circumstance. Choosing a system works more like this.

  1. Discuss what your budget is.
  1. Ask a specialist what type of systems fit within your budget and property type.
  1. If multiple options arise choose the materials preferred and the treatment option. This could be something like a more earth-friendly system and so on. 


Septic tanks are more complex than most individuals know. When we think about them, we just think it’s a gross area that holds waste. And while that may be true, they are complicated systems that work in different ways to safely move effluent to drain feels or other chambers. 

Understanding which septic tank is good for your property is the first step. It’s also great to know what your budget can afford and what to expect for the installation costs.

With such a heavy investment, it is worth taking care of the septic tank and getting the recommended maintenance to last for a long time!

Leave a Comment