Leach Field vs. Drain Field: What’s the Difference?

Leach fields and drain fields keep your septic system flowing

Father and son washing dishes in the kitchen sink
Photo: MoMo Productions / DigitalVision / Getty Images
Father and son washing dishes in the kitchen sink
Photo: MoMo Productions / DigitalVision / Getty Images
Kyle Schurman
Written by Kyle Schurman
Contributing Writer
Updated Feb 24, 2025
Highlights

  • Both leach field and drain field refer to the area where your septic waste drains.

  • Septic pros use the terms interchangeably, with some areas of the U.S. preferring one over the other. 

  • Some pros use the terms to describe specific parts of the septic system.

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If you have a septic system, you have a series of perforated pipes that lead away from the septic tank and slowly drain its contents into the surrounding soil. Professionals use terms like leach field and drain field to refer to this system. But are there differences in leach fields versus drain fields? Learn about the importance of these septic drainage systems.

Are There Differences in How Leach Fields and Drain Fields Work?

When comparing leach fields versus drain fields, differences don’t really exist. The terms leach field and drain field commonly refer to the area where the liquid waste from the septic tank drains. Most local septic tank professionals use the two terms interchangeably. Some places in the United States primarily use the term leach field, while others use drain field based on regional preferences. Think of it like regional preferences for terms like soda and pop.

The septic system includes perforated pipes attached to the tank and buried a few feet under the ground. Installers surround the pipes with gravel and soil. As liquid waste enters the septic tank, it eventually flows into these pipes, where it seeps into the surrounding gravel and soil through the perforations.

The soil and gravel provide a natural filtration system. The filtered liquid eventually becomes part of the groundwater system.

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Leach Fields vs. Drain Fields: Differences in Functionality

Construction of a new septic system leach field
Photo: PlazacCameraman / iStock / Getty Images Plus / Getty Images

Although most people use the terms leach fields and drain fields interchangeably, a few professionals use these terms to refer to specific parts of the septic system.

Perforated Pipes

Some people exclusively refer to the perforated pipes that extend from the septic tank as part of the drain field. 

Trenches and Soil

Some people only refer to the trenches, gravel, and soil as part of the leach field. 

Overall System

If people refer to leach field and drain field interchangeably, they won’t differentiate the parts of the system with these terms. They would use one term to discuss the perforated pipes, gravel, trenches, soil, and septic tank.

Other Terms Beyond Leach Fields vs. Drain Fields

Depending on where you live, you may hear terms other than leach fields or drain fields used to refer to the drainage system of the septic tank. These can include:

  • Absorption bed

  • Absorption field

  • Infiltration system

  • Percolation area

  • Seepage field

  • Septic field

  • Septic disposal field

  • Soil absorption system

Frequently Asked Questions

With proper maintenance, leach fields’ and drain fields’ life expectancy is up to 50 years. However, poor soil conditions, heavy usage, and improper maintenance could cause either type of field to have a far shorter lifespan of 15 to 20 years. Having your drain field and septic tank inspected every five years should extend the system’s lifespan.

The size of your septic tank plays a role in determining the proper size of the drain or leach field. As a general rule, you should have 1 square foot of drain field size per gallon of septic tank capacity. However, you could install a leach field that’s as much as 2.5 square feet per gallon of septic tank capacity. Most professionals determine the right septic tank size and drain field size by the number of bedrooms in the house. A three-bedroom house needs a minimum 1,000-gallon septic tank, for example.

Your drain field or leach field should be 1 to 3 feet under the ground. It will be a little shallower than the septic tank, although it can be the same depth or slightly deeper. The proper depth of the septic tank is up to 4 feet. It’s possible that your local regulatory agency requires a certain depth for your drain field.

You should exercise care when deciding how to landscape over a leach field for your septic system. You typically want lightweight materials that won’t damage the drain field’s perforated pipes. When adding plants to the area, select plants with shallow roots, such as grass or flower gardens. Trees with deep roots could damage the pipes in the field.

You only need to pump the septic tank. The leach field allows the liquid and waste to naturally seep into the ground, so there’s no need to pump the leach field. You should call a local septic tank pumping service to remove the materials from the tank every three to five years. Without pumping the septic tank occasionally, solids could flow into the leach field pipes and clog them.

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Kyle Schurman
Written by Kyle Schurman
Contributing Writer
Kyle Schurman has a passion for writing about topics ranging from home improvement to consumer electronics. His writing appears in online publications like Business Insider, New York Magazine, Scary Mommy, and multiple Tribune Publishing websites.

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