LARGER IMAGE: of a plastic or fiberglass septic tank. Septic Tank Inspection - How to Inspect Plastic or Fiberglass Septic Tanks

  • SEPTIC TANKS, FIBERGLASS / PLASTIC - CONTENTS: Characteristics of plastic septic tanks or fiberglass septic tanks. Types of Septic Tanks: steel septic tanks, concrete septic tanks, fiberglass septic tanks, home made septic tanks - definitions and characteristics of various types of septic tanks
  • SEPTIC TANK SIZE - separate article
  • POST a QUESTION or READ FAQs about fiberglass or plastic septic tanks: special problems, inspection, installation, troubleshooting, repairs, age, durability
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This document describes how to inspect the condition of a fiberglass or plastic septic tank, providing special considerations for inspecting Plastic or Fiberglass septic tanks, as those systems are subject to different stresses & possible failure or damage than concrete or steel tanks (that have their own concerns).

This article series answers just about any question about septic system inspection procedures, defects in onsite waste disposal systems, septic tank problems, septic drainfield problems, checklists of system components and things to ask.

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Guide to Plastic or Fiberglass Septic Tanks

Inspecting Plastic or Fiberglass septic tanks is a key component in onsite wastewater disposal systems. The plastic septic tank shown in this photograph is courtesy of thenaturalhome - link provided below.

Fiberglass or Plastic Septic Tanks: are very resistant to some of the problems occurring with concrete (cracks) or steel (rust) septic or home made (collapse) septic tanks. But plastic septic tanks can have their own special considerations, particularly during installation and possibly when the plastic or fiberglass septic tank is being pumped. Here are some things to watch for when inspecting a plastic septic tank or a fiberglass septic tank:

  • Low effluent level in a fiberglass or plastic septic tank may be discovered when the tank is opened for pumping. After the tank is emptied, check to see if a plastic plug from the tank bottom has been lost. One reader wrote to tell us that when her septic tank was pumped the pumping process itself dislodged and removed a plug from the tank bottom.

    The loss was discovered several years later when the tank was opened for pumping again. After cleaning the plug was replaced. (DO NOT ENTER A SEPTIC TANK for any reason, including replacing a plug, unless you are trained and have the required breathing equipment and a buddy watching - methane gas hazards in septic tanks can be fatal in minutes.

  • Damage during installation: a fiberglass septic tank may be damaged during installation, such as having been dropped or hit by equipment during installation. The resulting crack and leak may not be evident until later when the plastic or fiberglass septic tank is pumped. Look for abnormally low effluent levels and no missing drain plug.

  • Damage to piping connections: if a fiberglass or other light-material septic tank is left empty after installation or after pumping, and if the septic tank in an area of wet soils or rising ground water the tank can float up out of the ground, breaking plumbing connections and damaging the tank.

Fiberglass or Plastic Septic Tank Warranties & Life Expectancy

See the septic tank warranty notes by manufacturer beginning at REFERENCES below. Contributions are invited.

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Technical Reviewers & References

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