What is a Leach Field? Here’s What You Need To Know

If you have a septic system on your property, you may have heard the term “leach field” or “septic leach field.” But what exactly is a leach field, and how does it work? In this comprehensive blog post, we’ll answer the question, “What is a leach field?” and provide you with everything you need to know about this essential component of your septic system.

What is a Leach Field?

A leach field, also known as a septic field, drain field, or absorption field, is a crucial part of a septic system. It is an underground area where wastewater from your septic tank is dispersed into the soil for filtration and treatment.

How Does a Leach Field Work?

  1. Wastewater from your home enters the septic tank, where solids settle to the bottom and form a sludge layer, while oils and grease float to the top, creating a scum layer.
  2. The liquid wastewater, or effluent, flows from the septic tank into the field through a series of perforated pipes.
  3. The effluent is evenly distributed throughout the field, where it slowly seeps into the soil.
  4. As the wastewater percolates through the soil, it is filtered and treated by natural processes, including microbial action and adsorption.
  5. The treated wastewater eventually reaches the groundwater or evaporates into the air.

Components of a Leach Field

A typical septic leach field consists of several key components:

Distribution Box

The distribution box is a small concrete or plastic container that receives the effluent from the septic tank and distributes it evenly among the field pipes.

Perforated Pipes

The leach  contains a network of perforated pipes, also known as laterals or leach lines. These pipes are usually made of plastic and have small holes or slits that allow the effluent to seep into the surrounding soil.

Gravel or Crushed Stone

The perforated pipes are surrounded by a layer of gravel or crushed stone, which helps to distribute the effluent evenly and prevents soil from clogging the pipes.

Geotextile Fabric

A layer of geotextile fabric is placed over the gravel or crushed stone to prevent soil from mixing with the drainage material and to maintain the leach field’s structural integrity.

Maintaining Your Leach Field

To ensure that your septic field functions properly and lasts for many years, it is essential to follow these maintenance tips:

  1. Conserve water to avoid overloading the septic system and field.
  2. Avoid using harsh chemicals and antibacterial soaps, which can disrupt the delicate balance of microorganisms in the septic tank and field.
  3. Do not drive or park vehicles on the field, as this can compact the soil and damage the pipes.
  4. Keep trees and shrubs with deep roots away from the field to prevent root intrusion and damage to the pipes.
  5. Have your septic tank pumped regularly (every 3-5 years) to prevent solids from entering and clogging the  field.


Now that we’ve answered the question, “What is a leach field?” and provided a comprehensive overview of its function and maintenance, you have a better understanding of this essential component of your septic system. By taking proper care of your septic field, you can ensure that it continues to effectively treat wastewater and protect the environment for years to come.