Single vs. Double Compartment Septic Tank: Which One to Use?

Single vs Double Compartment Septic Tanks: Comparison
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Single vs. Double Compartment Septic Tank: Which One to Use?

As the trend towards self-sufficiency and living off the grid gains momentum, managing one’s waste has become an essential issue. For homeowners in remote or rural settings that lack public sewer connections, the significance of septic tanks cannot be overstated.

This article examines the differences between single- and double-compartment septic tanks, their specific use cases and the advantages of choosing plastic tanks over their concrete counterparts.

Single vs. Double Compartment Septic Tanks

Single Compartment Septic Tanks

single-compartment septic tank is the most basic and common type of tank used in residential sewage treatment systems. The tank has one chamber that holds all of the incoming wastewater and allows for the separation of solids from the liquid effluent. The single-chamber design is simple, cost-effective and generally works well for smaller homes with low water usage.

However, single-compartment tanks may not provide the same level of solids retention and effluent quality as double-compartment tanks, which can potentially lead to increased maintenance requirements and a greater risk of drain field clogging.

Double Compartment Septic Tanks

double-compartment septic tank is designed with two distinct chambers. Typically, the first chamber is larger than the second one. In the first chamber, raw sewage is collected and allowed to settle. As it settles, heavier solids sink to form a layer of sludge at the bottom, while lighter materials like grease and oils rise to create a scum layer on the surface.

The liquid effluent between these layers then moves into the second chamber. The second chamber acts as an additional treatment stage to provide further settling and digestion of any remaining solids. The end result is a higher-quality effluent that is eventually discharged into the drain field.

Dual-compartment septic tanks offer several benefits including:

  • Better solids retention
  • Improved effluent quality
  • Reduced risk of drain field clogging
  • Longer tank lifespan

The improved solids retention also means that the tank will require less frequent pumping and maintenance. The enhanced performance of double-compartment tanks makes them a popular choice for larger homes, commercial properties or areas with stricter environmental regulations.

Choosing Between Single and Double Compartment Septic Tanks

When deciding between a single and double-compartment septic tank, it’s important to consider the following factors:

Property Size and Water Usage

Single-compartment tanks are generally more suitable for smaller homes with low water usage while double-compartment tanks are recommended for larger homes, commercial properties or those with high water usage.

Environmental Regulations

Double-compartment tanks provide improved effluent quality and may be required in areas with more stringent wastewater treatment requirements.

Maintenance Frequency

Double-compartment tanks typically require less frequent pumping and maintenance, which can be a cost-saving benefit over time.

Initial Cost

Single-compartment tanks are generally less expensive to install than double-compartment tanks, but the latter may provide more long-term savings due to lower maintenance costs.

Plastic vs. Concrete Septic Tanks

While concrete has been the traditional choice for septic tanks, plastic tanks have gained popularity in recent years due to their numerous advantages. Plastic septic tanks are lightweight and easier to transport and install, which reduces labor and installation costs. 

They are also less susceptible to cracking, corrosion and leaks to ensure a longer lifespan and a reduced risk of environmental contamination. Additionally, plastic tanks are generally more cost-effective than their concrete counterparts.

Product Recommendations from Tank Depot

For those seeking reliable septic tank options, Tank Depot has a variety of high-quality single and double-compartment plastic tanks to suit your needs.

Single Compartment Septic Tanks

Norwesco 1,000 Gallon Single Compartment Septic Tank

The Norwesco 1,000 Gallon Single Compartment Septic Tank is a lightweight, durable plastic tank that is suitable for small homes and properties and provides efficient wastewater treatment with minimal maintenance requirements.

Ace/Den Hartog 1,250 Gallon Single Compartment Septic Tank


The Ace/Den Hartog 1,250-Gallon Single Compartment Septic Tank features a larger capacity tank designed to handle the wastewater treatment needs of medium-sized homes or properties with moderate water usage.

Double Compartment Septic Tanks

Norwesco 1,500 Gallon Dual Compartment Septic Tank


The Norwesco 1,500 Gallon Dual Compartment Septic Tank is ideal for larger homes and commercial properties, as it boasts an improved solids retention capacity and reduced maintenance frequency due to its dual-compartment design.

Norwesco 1,250 Gallon Dual Compartment Plastic Septic Tank

The Norwesco 1,250 Gallon Dual Compartment Plastic Septic Tank is a low-profile septic tank that has been manufactured in a single piece, which eliminates the need for extra assembly. This greatly reduces installation time and effort. 

The tank is extremely robust as it is formed through rotational molding and has no seams, decreasing the likelihood of leaks. This tank does not need special backfill or water filling during installation. Additionally, it can be pumped dry easily during pump-outs.

Upgrade Your Wastewater Management Today with Tank Depot’s High-Quality Plastic Septic Tanks

Plastic septic tanks from Tank Depot are a dependable and budget-friendly choice for homeowners and property managers seeking sturdy and lightweight wastewater management alternatives to conventional concrete tanks. We offer the highest quality septic and water storage tanks at the guaranteed lowest prices. 
Contact us today to find out more or locate a store near you!

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