LARGER VIEW of this COLLAPSING home made septic tank built using concrete blocks - an expert can find clues and perform tests that reduce risk of a costly surprise

Guide to Septic Tank Failures
Easy Guide to Inspection & Testing When Buying a Home With a Septic Tank

This home buyers guide to septic systems article describes what goes wrong with septic tanks, drainfields, and other septic system components. Septic backups, failures, breakouts, odors are often traced to clogged sewer lines, failing drainfields or soakaway beds, or improper piping or septic component installation. This document provides advice for home buyers who are buying a home with a private septic system: homes using an on-site septic tank and drainfield or similar soil absorption system.

Chapter 4 in this article series outlines what goes wrong with septic systems and their various components. Chapter 5-recommends and describes septic inspection and test methods in more detail, explains how to be sure your septic inspection and septic test are conducted properly, tells you where to get more septic system information about a given property, and warns of unsanitary or dangerous site conditions.

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4-What Goes Wrong with Septic Systems, Tanks, and Leaching Beds?

PHOTO of a septic seepage pit collapse when a truck drove over it.Do not drive over the septic tank or septic piping

Unless special provisions have been made such as protection of piping and septic tanks from damage, vehicle-rated septic tank covers, or similar steps, do not drive vehicles over the septic system.

Driving over septic tanks, septic piping, or drainfields risks costly damage to the septic system and may also be dangerous.

The bulldozer in our photo (left) was called to help remove a truck which drove over septic system components leading to a surprise collapse.


Home made or "site built" septic tanks, often using dry-stacked concrete blocks or even stone can collapse, a fatal hazard if someone falls in.

Photograph of a collapsing, impacted, failed home made septic tank.The septic tank shown in the photo at the top of this page had a concrete cover but when the cover was removed we found that the tank was under-sized, built of concrete blocks, and totally impacted with waste, as shown in this open septic tank photo. The system was inadequate, not working, and required replacement.

A proper loading and dye test would probably have detected this failure since the new owners had effluent in their yard within 24 hours of moving into the home.

Home made septic tanks which are way too small, such as the 100-gallon home made septic tank shown in the upper left of this photo of a too-small septic tank will simply not be functional for normal use.

Steel septic tank baffles rust off, sending solids into the leach field, shortening its life.

Photograph of a collapsing, failed steel septic tank.A steel tank baffle is visible in the lower left of this photo.

Watch out: steel septic tanks rust out and collapse, often sending solids into the leach field and reducing its future life as well.

Watch out: Septic tank covers themselves can also collapse, especially if made of steel as shown in the same photo as mentioned above. Falling into a septic tank is very likely to be fatal.

Other septic tank covers may be made of wood which eventually rots and collapses.

Collapsing septic tanks, steel, home made, or any type, are very dangerous. Falling into a tank is likely to be fatal.


Concrete septic tanks such as shown here are pretty durable but they can crack and leak or may have an unsafe cover.

Photograph of a collapsing, failed steel septic tank.The concrete septic tank shown in this photo is being installed at a new home.

The distribution box has not been placed and is still sitting atop the septic tank. This is a great time to measure and record the exact location of the septic tank and its cleanout access covers.

    Concrete tank baffles can deteriorate, crack, break, fall off. Baffles are checked when the septic tank is opened for cleaning.



Fiberglass or plastic septic tanks such as shown just below are also quite durable but may be cracked or damaged during installation or if driven-over later.

Photograph of a collapsing, failed steel septic tank.Septic Tanks which are not pumped often enough can become filled with sludge and scum, becoming totally impacted. Well before this condition is detected, such systems have sent solids into the leach field, shortening its life.


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