Aerobic Septic Problems & Case Studies

Browse our collection of aerobic septic system problems and issues. This resource library combines common maintenance issues with in-depth case studies from real installations — all documented to help homeowners recognize, prevent, and address septic failures before they become costly.

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Many problems can be prevented just by keeping up with basic maintenance and having your septic system inspected regularly. Regular inspection and service greatly extends the life of your aerobic treatment unit.

Common Problems

Issues that arise from deferred maintenance or normal wear — and how to spot them during routine inspections.

Air Pressure

During our inspection visit, one of the main things we check for is the air system on your aerobic treatment unit. If your septic system's air pressure is too high or low, it could cause several different problems depending on its pressure range.

Side-effects of HIGH air pressure:

  • • More frequent pump-outs.
  • • High solids build-up in pump tank.
  • • Premature air pump failure.
Very little air is entering the effluent inside an aerobic treatment unit

This is an example of HIGH air pressure in the treatment tank. (almost no bubbles)

Benefits of NORMAL air pressure:

  • ✓ Less frequent pump-outs.
  • ✓ Bacteria can breakdown solids and waste more efficiently.
  • ✓ Helps extend the lifespan of your air pump.
Much more air is entering the effluent inside the ATU, this is good

The bubble count is much higher after cleaning the air stones. (much more air entering water)

Side-effects of NO air pressure:

  • ! Bad odor.
  • ! Untreated wastewater sprayed onto lawn.
  • ! Constant alarm state on controller.

This could be caused by any of several issues (broken pipe, damaged diaphragms, clogged intake filter, etc.)

Wire Connections

Some installers and manufacturers make wiring connections for the water pump inside the pump tank. However, the water in the pump tank produces hydrogen sulfide gas and chlorine gas from the chlorine treatment. Both of these compounds are highly corrosive.

Corroded wires will cause a short in the water pump and possibly even a short in the controller.

High Solids? Time to Pump!

There are multiple compartments in your treatment unit. We check the levels in each one during our inspection visits to help prevent future issues that may arise with your septic system.

High Solid Level in aerobic treatment system

Side-effects of high solids:

  • • Premature water pump failure.
  • • Solids spraying onto lawn.
  • • Clogged filters, backed-up system.

Need more info? Check out our section on Septic Pumping

Inaccessible Openings

Septic tank openings are buried

Buried, or otherwise inaccessible tank openings, present a wall of sorts to maintenance providers such as ourselves. It prevents us from fully inspecting your system. We're unable to determine if the septic system needs pumping, has aeration problems, or has a working aerobic chamber.

Additionally, when you have your aerobic treatment tank vacuumed out, most pumping companies will charge extra to dig these openings up, or even worse, not bother with them at all, leaving only part of your tank clean.

Root Infiltration

These roots have infiltrated this pump tank

Many times, when a tree grows nearby an aerobic septic system, its roots will find their way inside. Even if the tree is over 15 feet away from your main tank, roots branch out and then expand, causing damage to pipes, conduit, or even your tank.

This root barrier stops grass roots from entering the septic tank

The best way to avoid this is to keep trees and large shrubbery away from your septic system. If needed, in certain situations we'll install a root barrier, preventing smaller roots from entering your tank. (Tanks installed at ground level can be infiltrated by grass roots, even though they're tiny!)

Uncommon Problems (Case Studies)

Other types of aerobic septic problems can be caused by factors outside of our control — these issues can smolder for years before manifesting. See our well-documented case studies on some of these types of problems below.

Case Study #1

Missing Trash Tank

Background

Single-Tank Aerobic System

Before a manufacturer of an aerobic wastewater treatment system can sell a particular model in Texas, it is sent to a testing facility for a rigorous six month operational test.

These six month long tests cost a manufacturer $250,000 for each different model tested. After receiving the TCEQ seal of approval, that system must be installed as tested by the facility. For obvious reasons, there can be no changes to the installation procedures and equipment.

This case study is about a TCEQ-approved two-tank aerobic wastewater treatment system (trash/pre-treatment + ATU) installed without the trash/pretreatment tank (ATU only).

Situation

Twenty years ago, the environmental health department of a county on the gulf coast arbitrarily changed the design parameters of a TCEQ approved waste water system. Years later, Advanced Aerobic Systems became the maintenance provider for new clients who all had the same complaint: during heavy rain/storm events, or high tides (neap tides) their aerobic wastewater system would back up into their elevated beach homes.

Observations

These county-permitted wastewater systems were installed without the TCEQ-mandated trash tank. Sewer effluent from the elevated home flowed directly into the treatment compartment. There was no pre-treatment (settling out of solids) as you would normally have with a trash tank.

The solids are now circulating in the treatment compartment. Compounding the problem, the tank design has an opening directly over the common wall that separates the treatment and clarifier compartments.

When the disposal field became water logged during a heavy rain event or high tide, everything backed up into the home. The elevated water level in the tank allowed the solids from the treatment tank to flow over the common wall into the clarifier. As the water table lowered, solids from the clarifier would then flow into the 8" gravel less pipe in the disposal field. Eventually the disposal field will fill with solids.

Solution

Always install according to tested specs. A separate trash tank needs to be added to these systems. Don't cut corners!

Case Study #2

Cracked Tank

Background

Before a manufacturer of a particular OSSF can sell their model in Texas, it is sent to a testing facility for a rigorous six month regimen. If the tank cracks during the test it will fail outright. These tests cost the manufacturer $250,000 for each tank. This case study is about an OSSF that had numerous cracked walls.

Situation

Cracked aerobic septic tank

Advanced Aerobic Systems became the maintenance provider for an installed OSSF located adjacent to a river. The owner wanted a maintenance contract in place before selling his 4 bedroom home. The tank was three years old.

Observations

Our inspection of the one tank, 4 compartment OSSF revealed low water in all 4 compartments. Upon further inspection Advanced Aerobic Systems found large cracks in the common interior tank wall that the pump tank has with three other compartments (trash, treatment and clarifier). In addition, the pump tank exterior wall was cracked, allowing effluent to escape into the ground.

The effluent in the trash, treatment, and clarifier compartments leaked into the pump tank compartment due to multiple cracks in the common wall separating them. This caused the water level in all tanks to equalize, and ultimately led to untreated effluent with harmful pathogens being pumped out onto the ground.

A detailed inspection was completed and provided to the owner, along with multiple pictures of the tank. We also informed the county of the situation, providing them with our recommendation to replace the cracked tank.

The outer wall of this aerobic unit is cracked, you can see the sand pouring in from outside

Action

The owner wanted a second opinion from the original installer. That installer said "don't worry about it because the cracks will eventually seal themselves with silt and the tank will work ok".

The county inspector visited the site and because they didn't find "solid waste overflowing" from the system they closed the case. The county indicated that either the owner or installer had to prove that coliform bacteria (pathogen indicator) was being pumped to the spray field. This required taking a water sample to the lab. However, this procedure is not required in this county and therefore was not included on the maintenance contract.

On the prima facie evidence of cracked walls and uniform low water levels, other counties would require either the tank be satisfactorily repaired or replaced.

Solution

Ultimately the county did not take further action. The owner sold the house to someone new, who now has no idea their tank is pumping untreated pathogens onto the ground.

Need help diagnosing or fixing a septic issue?

Advanced Aerobic Systems brings direct owner involvement and decades of experience to every inspection and repair. We'll walk you through what's wrong and what needs to happen next.

Call (281) 431-0123 Request Service