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5 Different Types Of Residential Septic Systems (Pros and Cons of Each)

different types of septic tanks

If you’re replacing an old system or putting one in a new house, there’s a lot to know about septic systems. There are many different types that you can go with.

In this post, we’ll take a look at the 5 most popular ones, and we’ll discuss the pros and cons of each.

Purpose of a Septic System

Before looking at the different types of systems, it’s worth pointing out the purpose of a septic system. This system will make sure your fluids and waste properly go down your drains and toilets.

In a good septic system, the waste decomposes, and the fluids drain after a certain level. The fluids are sent to a separate, underground area in which the soil will soak up the liquids.

Your septic system should provide a clear, unobstructed path from your toilets and drains all the way to your septic tank. To put it simply, this system keeps the toilet waste out of your house.

Why Does it Matter?

As you read, you’ll notice there are slight differences between each system (with the exception of #4). Why does it all matter?

Well, your septic system is a sizable investment. You want to make sure you’re not wasting your money by picking the wrong one.

For people looking for a residential option, any of the below options might suffice. You will find, however, that your plot size and topography might make the decision for you.

Small plots don’t have the real estate required for a conventional system. Neither do especially mountainous terrains.

Now let’s take a look at 5 septic systems and the pros and cons of each.

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Different Types Of Residential Septic Systems

1: Conventional System

This is the system you’ll usually see at a single-family home or a small business. In a conventional system, your waste goes to a septic tank.

The tank feeds to a distribution box that branches into multiple runs. Each of these runs allow the liquid to drain into the surrounding earth.

These runs are positioned on top of layers of sand, gravel, and fine rocks. Additionally, there is a material positioned above each of these runs that make sure the elements stay out of the tubes.


Since these are the most common septic systems, professionals have an easier time fixing them. Also, this system is easy enough to repair on your own. Another great benefit is that this is the least expensive option.


The problem arises when you’re looking at a property on a small lot. You need a lot of space for the liquid to drain.

2: Chamber System

A sister to the conventional system is the chamber system. They started getting popular in the early 90s. As technology got better, people realized that they could do away with the gravel pits in the conventional system.

Instead of using gravel during the draining process, the chamber system opts for a chamber (can you guess how they named this system?).

After the distribution box, the liquids travel through connected chambers. All around the chambers is dirt, and the liquid ultimately drains into the dirt as well.


This chamber is easier to build since it uses a pre-manufactured chamber. This option is also great for areas with high groundwater tables. The price is comparable to the conventional system.


There is more maintenance required because of the restricted access to the drain field and the added parts.

3: Conventional Pump System

In this flow diagram, we take another step. Between the distribution box and septic tank, there is a pump tank.

Why use a pump, you ask? This is the preferred system if your drain lines are going to be uphill from where your tank is.

These systems can use gravel or gravel-less options for the drain lines.


The pump system is favored in mountainous or hilly terrains. The price is affordable for this system.


The downside is that there are more moving parts that lead to more required maintenance.

4: Aerobic Treatment Unit

An Aerobic Treatment Unit is also called an ATU. In an ATU, you will see properties that are reminiscent of a sewage plant. It uses a lot of the same principals and science, actually.

This system looks nothing like the previous 3 we discussed. The magic happens inside of this container.

This unit has an air pump that aerates the sludge and water in the tank. This additional oxygen allows for more natural bacteria which helps the process.

An ATU might have a treatment tank and/or a pretreatment tank to reduce the pathogens of the waste.


This unit can be used in properties with small lots, high water table, poor soil conditions, or with lots that are near bodies of water.


Due to the complexities of an ATU, you can expect a lot more maintenance.

5: Mound System

The last style to learn about is a mound system. In this case, you will use a mound of sand, gravel, and dirt instead of a traditional drain field.

This system is similar to the conventional pump system. The exception is the piece after the pump.

In a mound system, the waste gets pumped to a constructed mound. The drain field is fed at the top of the mound.

The gravel and sand help to treat the effluent as it flows down, before reaching the native soil.

You’ll find mound systems often in rural areas. Since houses are more spread out and properties typically have more acreage, homeowners will opt for this method.


The mound system is ideal for areas that have shallow soil or high groundwater.


Unfortunately, this system requires a lot of space. You’ll also find yourself maintaining the unit more frequently than some of the others on this list.

Bonus System: Cluster System

Though this style might not be useful to a lot of people, if you’re looking into a new system because you’re building new properties, you’ll like this.

A cluster system is used in residential areas where you have multiple houses near one another. All of the houses have their own septic tanks.

After each septic tank, the lines converge and are led to a treatment and dispersal area. This treatment system will clean the waste from all of the houses.

It’s then led to a large drain field. In this case, it can use whatever technology and method are desired for the drain lines.


Installing a cluster system is an easier alternative to individual systems. It’s the best option if you own a lot of properties that are close to one another. There is also less maintenance compared to servicing a number of separate systems.


This system is only reasonable for people who own two or more properties that are near one another.

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