Out of sight out of mind seems to be most people’s motto when it comes to septic tanks. But not familiarising yourself with the different septic tank types and the pros and cons of each before purchase could come at a cost, and a lot of agony.

We’ve first covered the differences between concrete and poly septic tanks in our blog post Poly Septic Tank vs Concrete mainly because many people might automatically assume concrete is the best choice (without knowing it might not be a match for their needs) or assume there aren’t any other alternatives out there.

Different Types of Septic Tanks 

Here are 4 types of septic tanks commonly available in Australia:

1. Concrete (See our blog post Poly Septic Tank vs concrete.)

2. Poly

3. Fibreglass

4. Aerobic tanks

This post will cover only the last 2 types of septic tanks along with their advantages and disadvantages. 

Fibreglass

Disadvantages:

• Although fibreglass itself doesn’t corrode, localised corrosion might occur in other parts that aren’t rust-resistant.
  
• In relation to the above, fibreglass is not constructed as a one-piece container. It has seams, which are vulnerable areas to these types of tanks.
  
• Handcrafted and labour extensive. Implication: more susceptible to human error during production
  
• More vulnerable to damage with soil shifts e.g. traffic or heavy vehicles passing over the septic tank
  
• Can be more expensive than poly tanks 
  
• Can easily crack

Advantages:

• Being light, fibreglass is easier to install compared to concrete.
• Resistant to chemicals, just like poly septic tanks.
  

Right (foreground): 2,200-litre poly septic tank; left: 1,450 litre poly septic tank from Coerco.

Aerobic septic tanks

Disadvantages:

• Needs electricity to operate
• More expensive
• Because it uses oxygen to accelerate effluent decomposition, pumping can be less frequent compared to other types of septic tanks.
  
  However, this doesn’t mean it needs less frequent maintenance. In fact, it needs more maintenance.
  
  

A complex system such as this increases the likelihood that something can go wrong, which necessitates more frequent maintenance compared to the regular maintenance required for other types of septic tanks.

Advantages: 

• Doesn’t take too much space
• May require lesser space for the drain field.

Now that you know about 3 more different types of septic tanks and their pros and cons,  you might wonder where poly septic tanks fit in all this.

Just why is poly septic tank a better alternative?

The Poly Septic Tank Advantage

In a nutshell:

• Rotationally moulded poly septic tanks are seamless and strong on all sides. As rotational moulding is an automated process, opportunities for human error at this stage of production are but few.

• Poly septic tanks are non-porous. No need to worry about roots of plants or trees boring a hole through your poly septic tank.

• Plastic septic tanks are highly resistant to the chemical processes that happen naturally in a septic system. 
  

• No seams/connectors that are vulnerable to corrosion.

   

  Making an informed decision is easier when the alternatives are clear to you. When it comes to septic tanks, a lapse in knowing what’s best for you can result in costly repairs in the future and compromise the comfort and functionality of your property.
  
  
  Related article: 
  
  What You Need to Know Before Septic System Installation (A Checklist)