When it comes to managing wastewater in rural or off-grid areas, septic systems are an essential solution. Choosing the right septic system for your property can be a daunting task given the variety of options available. Factors such as soil type, lot size, budget, and local regulations can all influence which septic system is right for you.
In this comprehensive guide, we will explore the different types of septic systems, how they work, and the best applications for each.
This will help you make an informed decision and ensure that your septic system serves your needs while also protecting the environment.
What is a Septic System?
A septic system is an on-site wastewater treatment solution used in areas without access to municipal sewers. It processes waste from your home—including toilets, sinks, showers, and laundry—and returns treated water safely to the environment. Septic systems come in various designs, each suited to specific conditions and requirements.
A typical septic system consists of a septic tank and a drainfield (also known as a leach field). Wastewater flows from your home into the septic tank, where solids settle at the bottom (sludge) and lighter particles float to the top (scum). The clarified liquid then flows into the drainfield, where it is filtered by soil and further treated by natural microbes.
Septic Systems Overview Table
| Septic System Type | Best Suited For | Advantages | Disadvantages |
| Conventional System | Properties with good soil and enough space | Cost-effective, easy to maintain, suitable for a variety of soil types | Requires large land area, may not work well with high water tables |
| Chamber System | Areas where gravel is scarce or excavation is difficult | Less excavation needed, adaptable to high groundwater areas | May be less efficient compared to gravel systems |
| Drip Distribution System | Properties with limited space or uneven terrain | Less lawn disruption, even wastewater distribution | Requires pump and regular maintenance, higher cost |
| Aerobic Treatment Unit (ATU) | Environmentally sensitive areas or poor soil conditions | High level of treatment, suitable for small lots | Requires power source, regular maintenance, higher cost |
| Mound System | Sites with high water tables or shallow soil | Prevents groundwater contamination, good for shallow soil | Requires space and regular maintenance, visually intrusive |
| Recirculating Sand Filter System | Properties near sensitive water bodies requiring extra treatment | Provides high level of treatment, effective near water bodies | Complex installation and maintenance, higher cost |
| Evapotranspiration System | Arid climates with minimal rainfall | No groundwater contamination, good for dry climates | Only suitable for dry climates, may fail in heavy rain |
| Constructed Wetland System | Properties near natural wetlands or needing high nutrient removal | Environmentally friendly, effective at nutrient removal | Requires careful planning, needs more space |
| Cluster/Community System | Rural subdivisions or multiple households sharing treatment | Economical for multiple homes, shared maintenance responsibilities | Shared ownership and maintenance responsibilities |
What are the different types of septic systems
- Conventional Septic System
- Chamber Septic System
- Drip Distribution Septic System
- Aerobic Treatment Unit (ATU)
- Mound Septic System
- Recirculating Sand Filter Septic System
- Evapotranspiration Septic System
- Constructed Wetland Septic System
1. Conventional Septic System
The conventional septic system is the most common type used in single-family homes. It consists of a septic tank and a drainfield, which is usually a shallow trench filled with gravel or stone.
Effluent from the septic tank is piped into the drainfield, where it percolates through the soil and is treated by natural bacteria.
Conventional septic systems are widely preferred due to their simplicity and affordability. They are especially ideal for properties with large yards and good soil conditions that allow for effective percolation.
This system is straightforward in its design and operation, which makes it an attractive choice for homeowners seeking a reliable wastewater management solution. The drainfield plays a key role in the treatment process, filtering the effluent as it passes through the soil, where naturally occurring bacteria further treat it.
How Conventional Septic System works
House and Waste Pipe
Wastewater from the house—including toilets, sinks, showers, and laundry—flows through the Waste Pipe to the Septic Tank.
Septic Tank
The Septic Tank is an underground, watertight container where wastewater is held. Here, the waste separates into three layers:
- Scum Layer: Oils, fats, and grease float to the top, forming the scum layer.
- Effluent: The liquid layer in the middle is called effluent. This is the treated water that will move on to the next stage.
- Sludge Layer: Heavier solids sink to the bottom, forming sludge.
The effluent leaves the septic tank through an Effluent Pipe while the scum and sludge remain behind.
Drainfield (Leach Field)
The effluent flows through the effluent pipe into the Drainfield, which is a shallow, excavated area filled with gravel or stone.
- Perforated Pipes are laid in the gravel-filled trench to evenly distribute the effluent.
- As the effluent is released from the pipes, it percolates through the gravel and into the surrounding Soil (Effluent Dispersal Area).
Soil Treatment
The Soil acts as a natural filter, treating the effluent as it percolates downwards. Microbes in the soil help break down any remaining harmful bacteria, pathogens, and nutrients before the treated water reaches the groundwater.
The Conventional Septic System is effective for properties with good soil conditions and adequate space for a drainfield. It is cost-effective, easy to maintain, and uses natural processes to treat wastewater efficiently before it is returned to the environment.
2. Chamber Septic System
The chamber septic system is similar to the conventional system but replaces the gravel in the drainfield with connected chambers. The chambers create an open space around which the soil treats the effluent.
Chamber systems offer flexibility in situations where conventional gravel drainfields are impractical. The chambers provide an alternative means of dispersing effluent, allowing it to come into direct contact with the soil for treatment. This system is particularly useful in areas with limited gravel availability or where excavation is challenging.
The use of chambers also means that these systems can be more environmentally friendly, as they can be made from recycled materials. However, they may require more attention to ensure that the soil surrounding the chambers remains effective for filtration.
How Chamber Septic System works
Home to Septic Tank
Wastewater from the home—including from toilets, sinks, showers, and appliances—flows out through a waste pipe into the septic tank.
Septic Tank
- In the septic tank, the wastewater separates into three layers
- Scum Layer (top): Oils, fats, and grease float to the top.
- Effluent (middle): The liquid part of the wastewater that is ready for treatment.
- Sludge (bottom): Heavy solids settle at the bottom.
- The effluent is piped out of the septic tank while the scum and sludge remain in the tank.
Chamber System
- The effluent then flows from the septic tank into the Chamber System. The chambers are underground, open-bottom structures that replace the traditional gravel drainfield.
- The chambers allow the effluent to spread out evenly into the soil surrounding the chambers.
Soil Treatment
- As the effluent flows out of the chambers, it percolates through the surrounding soil.
- Natural microbes in the soil help to further treat the effluent by breaking down any remaining pathogens and contaminants.
- This soil treatment ensures that clean water eventually reaches the groundwater without causing contamination.
The Chamber Septic System works well in areas where gravel is scarce or difficult to obtain, or where excavation is challenging. The chambers create an efficient space for effluent distribution and allow the surrounding soil to perform the final treatment of the wastewater. This system is also useful in areas with high groundwater levels or where consistent soil filtration is necessary.
3. Drip Distribution Septic System
The drip distribution system uses a network of small-diameter pipes installed near the surface of the soil. The pipes are designed to distribute wastewater evenly, allowing for better absorption.
Drip distribution systems are an innovative solution for properties with space constraints or irregular terrain. Unlike conventional systems, drip distribution does not require a large mound of soil, making it less invasive to install. The system uses a pump to pressurize and distribute effluent through small-diameter pipes laid close to the surface.
This even distribution ensures that wastewater is treated effectively by the soil. While this system is more complex and requires a pump, it is an excellent option for properties that cannot accommodate traditional drainfields.
How Drip Distribution Septic System Works
Home to Septic Tank
Wastewater from the home (from toilets, sinks, showers, etc.) flows through a waste pipe into the septic tank.
Septic Tank
- In the septic tank, the wastewater separates into three layers:
- Scum Layer at the top (oils and grease).
- Effluent in the middle (liquid waste).
- Sludge at the bottom (heavier solids).
- The effluent leaves the septic tank through an effluent pipe, while the scum and sludge remain in the tank.
Pump Chamber
- After leaving the septic tank, the effluent enters a pump chamber. The pump is used to regulate the flow of effluent and ensure it is evenly distributed.
- The pump chamber helps to store the effluent until it is ready to be pumped into the drip distribution field in timed doses.
Drip Distribution Field
- The drip distribution field contains a network of small-diameter drip pipes that are laid out in the soil, usually at a shallow depth (6 to 12 inches below the surface).
- The drip distribution field contains a network of small-diameter drip pipes that are laid out in the soil, usually at a shallow depth (6 to 12 inches below the surface).
Effluent Dispersal and Soil Treatment
- The soil in the drip distribution field treats the effluent as it filters through. The natural microbes in the soil break down any remaining contaminants, providing additional treatment before the water reaches the groundwater.
- The drip system allows for even distribution, minimizing the risk of soil saturation and maximizing the effectiveness of the natural treatment process.
The Drip Distribution System is especially useful in areas with limited space or uneven terrain, as it doesn’t require a large mound of soil. The use of a pump to control the flow ensures that the effluent is evenly distributed across the field, which helps to prevent issues like soil saturation and makes it a reliable, effective system for treating wastewater. The diagram helps illustrate the flow of wastewater from the home, through the septic tank, pump chamber, and finally to the drip pipes that distribute it into the soil.
4. Aerobic Treatment Unit (ATU)
Aerobic Treatment Units function similarly to a small-scale municipal wastewater treatment plant. These systems use oxygen to boost the growth of aerobic bacteria, which helps to break down organic waste faster and more thoroughly.
Aerobic Treatment Units are highly efficient in breaking down waste and are particularly suitable for environmentally sensitive areas. By introducing oxygen into the treatment process, ATUs encourage the growth of bacteria that thrive in oxygen-rich environments, which significantly improves the breakdown of organic material.
This makes ATUs an ideal solution for properties near lakes, rivers, or areas with a high water table. However, they do require a consistent power supply and regular maintenance to function properly. Despite the higher cost, ATUs provide an effective solution where conventional systems are not feasible.
How aerobic treatment unit (ATU) work
Home to ATU
Wastewater from the home (from toilets, sinks, showers, etc.) flows through a waste pipe into the septic tank.
ATU Chambers
- Once in the ATU, the wastewater separates into three layers::
- Scum Layer (top): Oils and grease float here.
- Effluent (Aerated) (middle): Liquid wastewater that will be treated.
- Sludge (bottom): Heavy solids settle here.
Air Compressor
- The air compressor pumps air into the ATU, which adds oxygen to the effluent.
- This oxygen helps aerobic bacteria grow and break down the waste faster and more effectively.
Treated Effluent
The treated effluent then leaves the ATU through an effluent pipe. It is now much cleaner after being broken down by the aerobic bacteria.
Drainfield
- The treated effluent flows to the drainfield (or leach field). In the drainfield, the effluent is spread out and filtered through the soil.
- Natural microbes in the soil continue to treat the effluent, ensuring that clean water reaches the groundwater.
The ATU septic system uses oxygen to help bacteria clean the wastewater more thoroughly, which makes it better for homes that need a higher level of treatment, especially if the soil conditions are poor or the property is near sensitive water sources. The diagram helps you see how the waste flows from the home to the ATU, gets treated with air, and finally moves into the drainfield for further filtering.
5. Mound Septic System
The mound system is used in areas where the soil is too shallow for a conventional drainfield, or where the water table is too high. The system consists of a sand-filled mound that contains a drainfield trench.
Mound septic systems are designed to overcome site limitations such as shallow soil depth or high groundwater levels. The sand mound acts as an additional filtration medium, providing an extra layer of protection against groundwater contamination. This system is particularly beneficial in areas where the natural soil is not suitable for effluent absorption.
However, the installation of a mound system can be labor-intensive, requiring significant space and proper grading. The mound’s visibility may also be a concern for homeowners looking for a less conspicuous solution.
How Mound Septic System works
Home to Septic Tank
Wastewater from the home (from toilets, sinks, showers, and other sources) flows through a waste pipe into the septic tank.
Septic Tank
- Inside the septic tank, the wastewater separates into three layers:
- Scum Layer (top):Oils and grease float to the top.
- Effluent (Aerated) (middle): The liquid part that will move to the next stage.
- Sludge (bottom): Heavier solids settle at the bottom.
- The effluent (middle layer) then exits the septic tank through an effluent pipe.
Pump Chamber
After leaving the septic tank, the effluent enters the pump chamber. The pump helps move the effluent to the mound system at a controlled rate, ensuring even distribution.
Mound System
- The mound system is a raised bed filled with sand and gravel, built above the natural soil. It contains perforated pipes that distribute the effluent evenly across the mound.
- The mound provides extra filtration and helps treat the effluent before it reaches the natural soil below.
Effluent Dispersal in Soil
- Once the effluent is released through the perforated pipes, it percolates down through the sand and gravel and eventually into the natural soil.
- The soil provides further treatment, removing remaining contaminants and pathogens before the water reaches the groundwater.
The Mound Septic System is especially useful in areas where the natural soil is not deep enough, or where the water table is too high for a conventional drainfield. The raised mound provides a safe way to treat wastewater and keep it from contaminating the groundwater.
6. Recirculating Sand Filter Septic System
The recirculating sand filter system uses sand as a filtration medium to treat effluent before it reaches the drainfield. Wastewater flows through a septic tank to a pump chamber, then is pumped to the sand filter for additional treatment.
Recirculating sand filter systems are known for their effectiveness in providing advanced wastewater treatment. The sand filter helps to remove contaminants that may not be fully treated in a conventional septic system, making it suitable for environmentally sensitive areas.
Recirculating sand filter septic system requires a pump to move effluent through the sand, where it undergoes further treatment before reaching the drainfield. Due to the complexity of this system, it may require more frequent maintenance, but it provides a higher quality of effluent, which is crucial in areas with stringent environmental regulations.
How Recirculating Sand Filter Septic System Works
Home to Septic Tank
Wastewater from the home (such as from toilets, sinks, and showers) flows through a waste pipe and enters the septic tank.
Septic Tank
- Inside the septic tank, the wastewater separates into three layers:
- Scum Layer (top):Oils and grease float here.
- Effluent (Aerated) (middle): The liquid portion that will be treated.
- Sludge (bottom):Heavy solids settle to the bottom.
- The effluent (middle layer) exits the septic tank through an effluent pipe.
Pump Chamber
The effluent flows into the pump chamber, which helps control the flow of wastewater and ensures that it is pumped to the sand filter at regular intervals.
Sand Filter System
- The effluent is then pumped to the Sand Filter System, which has layers of sand and gravel.
- The effluent moves through these layers, and the sand and gravel help filter and treat the wastewater, removing contaminants.
Treated Effluent to Drainfield
- After passing through the sand filter, the treated effluent is sent to the drainfield through a treated effluent pipe.
- In the drainfield, the effluent is distributed into the soil, where it undergoes further natural treatment before eventually reaching the groundwater.
7. Evapotranspiration Septic System
The evapotranspiration system relies on evaporation rather than percolation. Wastewater enters a drainfield lined with an impermeable material, where it is evaporated into the air instead of being absorbed by the soil.
Evapotranspiration systems are unique in that they do not rely on soil absorption for wastewater treatment. Instead, the system uses natural evaporation and plant transpiration to dispose of effluent. This makes it an ideal choice for arid regions where soil percolation is not feasible.
The system is designed to prevent any wastewater from reaching the groundwater, providing a high level of environmental protection. However, it is only suitable for areas with consistent dry weather, as heavy rainfall can overwhelm the system and lead to failure.
How Evapotranspiration Septic System Works
Home to Septic Tank
Wastewater from the home (including from sinks, toilets, and showers) flows through a waste pipe and enters the septic tank.
Septic Tank
- In the septic tank, the wastewater separates into three layers:
- Scum Layer (top):Oils and grease float here.
- Effluent (Aerated) (middle): The liquid portion that will be treated.
- Sludge (bottom):Heavy solids settle to the bottom.
- The effluent exits the septic tank through an effluent pipe.
Evapotranspiration Bed
- The effluent flows into the evapotranspiration bed. This bed is lined with a watertight material and filled with layers of sand and gravel.
- The effluent stays in the bed, where it is evaporated into the air.
Evaporation Process
- The effluent evaporates from the bed and is released into the atmosphere. Unlike other septic systems, this system does not release the effluent into the soil.
- This process is only effective in areas with dry, arid climates that have enough sunlight to evaporate the wastewater.
8. Constructed Wetland Septic System
The constructed wetland system mimics natural wetlands to treat wastewater. The effluent flows from the septic tank into a wetland cell that contains gravel, sand, and wetland plants.
Constructed wetland systems are an environmentally friendly option that uses natural processes to treat wastewater. The wetland cell is filled with gravel and planted with wetland species that help filter and break down contaminants.
Constructed wetland system is particularly well-suited for properties near existing wetlands or in areas with high moisture levels. It provides effective nutrient removal and can be a visually appealing addition to the landscape. However, constructed wetlands require careful planning, including the selection of appropriate plant species and sufficient space for installation.
How Constructed Wetland Septic System Works
Home to Septic Tank
Wastewater from the home (from toilets, sinks, and showers) flows through a waste pipe and enters the septic tank.
Septic Tank
- In the septic tank, the wastewater separates into three layers:
- Scum Layer (top):Oils and grease float here.
- Effluent (Aerated) (middle): The liquid portion that will be treated.
- Sludge (bottom):Heavy solids settle to the bottom.
- The effluent exits the septic tank through an effluent pipe.
Constructed Wetland
- The effluent flows into the constructed wetland. This wetland area is designed to mimic natural wetlands and contains wetland plants that help treat the effluent.
- The effluent flows through the wetland, where it is further filtered by the plants, gravel, and microbes present in the wetland environment.
Treated Effluent to Drainfield
- After passing through the wetland, the treated effluent is sent to the drainfield through a treated effluent pipe.
- In the drainfield, the effluent is distributed into the soil, where it undergoes further natural treatment before eventually reaching the groundwater.
9. Cluster/Community Septic Systems
Cluster or community septic systems serve multiple dwellings, collecting wastewater from multiple homes and treating it at a shared treatment and drainfield location.
Cluster septic systems are an efficient solution for residential developments and rural communities where individual septic systems are impractical. By sharing treatment facilities and drainfields, homeowners can benefit from reduced installation and maintenance costs.
These systems can be particularly advantageous in areas where the cost of extending municipal sewer lines is prohibitive. However, shared systems require cooperation among homeowners for maintenance and management, which may pose challenges if responsibilities are not clearly defined.
How Cluster/Community Septic System Works
Homes to Main Sewer Line
Wastewater from multiple homes (e.g., from toilets, sinks, and showers) flows through individual waste pipes from each house to a main sewer line.
Main Sewer Line to Septic Tank
The main sewer line collects wastewater from all homes and directs it to a shared community septic tank.
Community Septic Tank
- In the community septic tank, the wastewater separates into three layers:
- Scum Layer (top):Oils and grease float here.
- Effluent (Aerated) (middle): The liquid portion that will be treated.
- Sludge (bottom):Heavy solids settle to the bottom.
- The effluent exits the septic tank through an effluent pipe.
Community Drainfield
- The treated effluent is sent to the community drainfield through an effluent pipe.
- In the drainfield, the effluent is evenly distributed into the soil, where natural soil microbes help treat it further before it eventually reaches the groundwater.
Outdated Septic Systems to Avoid
- Concrete Septic Tanks: These older tanks are prone to leakage and often lack a solid foundation, making them inefficient and environmentally unsafe. Concrete tanks can crack over time, leading to potential contamination of groundwater and posing serious health risks.
- Cesspools and Seepage Pits: These systems are outdated and often illegal because they allow untreated waste to enter groundwater, posing a significant health and environmental risk. Cesspools, in particular, are simply holes in the ground that collect waste, offering no filtration or treatment, which makes them highly dangerous for both human health and the environment.
Choosing the Right Septic System
Choosing the right type of septic system is crucial for protecting both your property and the environment. Each type has its pros and cons, and the decision ultimately depends on the unique characteristics of your property. Consulting with a septic professional ensures that you make an informed decision, providing effective wastewater management for decades to come.
Proper planning and regular maintenance will help keep your septic system functioning smoothly, preserving local water quality and avoiding costly repairs.
Choosing the right septic system is crucial for ensuring the safety of your family and the health of the environment. Each type has its pros and cons, and the decision depends on the unique characteristics of your property. By understanding the available options, you can equip your home with an effective wastewater treatment solution.
If you need assistance, consult a certified professional. Proper planning and ongoing care will help keep your septic system functioning smoothly for years.
Investing in the right septic system is about making a choice that benefits your family, budget, and the environment. Taking the time to understand your property’s needs will help ensure effective wastewater management for decades.
Regular monitoring and maintenance are key to keeping your septic system in good working order. Scheduling inspections, practicing mindful water usage, and addressing issues early can prevent costly repairs and extend the life of your system. With the right system and proper care, septic systems can provide a safe, efficient solution for managing household wastewater.
