Septic system drawing An Introduction to Septic Systems - the Basics

  • SEPTIC SYSTEM BASICS - CONTENTS: What is a septic system? - the basics for home owners and buyers of a home with a septic tank and drainfield or alternative septic system design
  • POST a QUESTION or READ FAQs about home septic systems: what is a septic tank, what is a drainfield? How do septic tanks work? How do drainfields work? What are the recomended steps to clean out or maintain septic tanks and drainfields?
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What is a septic system?

This article explains what a septic system is, with a brief description of how septic systems work and what are the main components of a septic tank and drainfield system. This article describes the basic function, design & care of private septic tanks & drainfields or soakaway beds.

Key articles for people unfamiliar with septic systems are listed here:

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An Introduction to Septic Systems - How do Septic Systems Work?

If you don't know if your building is connected to a public sewer or a private septic system, see SEPTIC or SEWER CONNECTION?.

What is a Septic System? Or What's a Septic Tank? What's a Drainfield? How do they work?

Sketch of a conventional septic system showing tank and drainfields

[Click to enlarge any image]

A "septic system," also referred to as a private, on-site waste disposal system, receives waste water and solids from a building's plumbing facilities (bathrooms, kitchens, shower, laundry), treats, and then disposes of the effluent from this waste, by permitting it to absorb into soils at the property.

Wastewater or septic effluent treatment is accomplished by bacterial (and other microorganism) action in the "septic" or "treatment" tank and it is mostly accomplished by bacteria in the soil around and below the effluent absorption system, or "drain field."

This bacterial action is needed to reduce the level of pathogens in the effluent discharges from the waste system into the soil. In addition to reducing the level of pathogens and the reduction of organic waste to a combination of new cell masses, CO2, and water, wastewater treatment removes organic matter, nitrites and nitrates, and phosphorous. In an absorption field the soil performs an additional role of filtering the septic effluent.

A bit more detail is at HOW SEPTIC SYSTEMS WORK

Where are the Septic Tank & Leachfield Usually Located on a Property & How are these components Laid-Out ?

The septic tank is usually located close to the building, perhaps just ten feet away, but on difficult sites a grinder pump may instead send wastewater to a more remote septic tank and drainfield. Incidentally, depending on where you live, the "drainfield" that absorbs & treats the final septic wastewater or effluent might be called a leachfield, leaching bed, drainage trench, soakaway bed or other terms. (Contact Us to suggest other septic system terms to include here.)

Septic system drawing

The principal components of a private on-site waste disposal system usually include the following:

Below is a simple sketch of a septic tank showing how solid waste leaving the building thorugh its main drain or wastewater piping or "sewer line" or "septic line" is retained inside the tank while liquid effluent flows to the drainfield. (Click images to see an enlarged version). Here are the main components of a septic system and a brief description of what each does:

Septic tank sketch

Many variations on this general scheme are used, depending on local climate, soil conditions, available space, economy, and available materials. Special equipment and systems may be designed for problem or difficult sites such as rocky or wet ground, permafrost, or wet tropical marshlands.

Helpful but still basic articles for owners of a property with a septic system include:


Continue reading at SEPTIC INFO for HOMEOWNERS, BUYERS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see SEPTIC CARE INSTRUCTIONS for specific advice about the septic tank


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SEPTIC SYSTEM BASICS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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