Is Your Septic Tank Aerobic or Anaerobic? Understanding Your Septic System

Is Your Septic Tank Aerobic or Anaerobic? Understanding Your Septic System


The distinction between aerobic and anaerobic septic systems is crucial for homeowners to understand, as it affects the maintenance, efficiency, and installation of the system.

Aerobic vs. Anaerobic Systems

  • Anaerobic Septic Systems: Most traditional septic systems are anaerobic. These systems do not require oxygen for the breakdown of waste. Bacteria in the tank thrive in oxygen-free environments, slowly decomposing the waste material.
  • Aerobic Septic Systems: Aerobic systems, on the other hand, use oxygen-loving bacteria to more quickly and efficiently break down waste. These systems often include an aeration pump that introduces oxygen into the treatment process.

How Each System Works

  1. Anaerobic Systems:
    • Functionality: Anaerobic bacteria break down solid waste, and the effluent then flows out into a drain field where further filtration occurs.
    • Installation: They are typically easier and less costly to install than aerobic systems, as they rely on natural processes and do not require electricity.
  2. Aerobic Systems:
    • Functionality: Oxygen increases the activity of the bacteria, resulting in a faster breakdown of waste. The treated water is often cleaner than that from anaerobic systems and can sometimes be used for irrigation.
    • Installation: These systems are more complex and costly, often requiring additional tanks, compartments, and electrical components.

Maintenance Requirements

  • Anaerobic System Care: These systems require regular tank pumping to remove solid sludge but typically have fewer mechanical parts.
  • Aerobic System Care: Aerobic systems need more frequent maintenance, including regular checks of mechanical components and electrical parts.

Choosing the Right System for Your Home

  • Consider the size of your property, local regulations, environmental concerns, and maintenance capabilities when choosing between an aerobic or anaerobic system.


Knowing whether your septic system is aerobic or anaerobic is essential for proper care and maintenance. Each type has its own requirements and benefits, and your choice should be informed by your home’s needs and environmental conditions.