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Concrete vs Plastic Septic Tanks (Why Concrete is Better)

By Graham’s Precast Concrete Products Pty Ltd • Apr 26, 2022



Concrete septic tanks in QLD are a vital component of every home and business—especially rural properties that are not connected to a sewage system.

Considering septic tanks operate as a chamber that allows the flow of wastewater for basic treatment, it’s important to have a system that’s highly durable and long-lasting. In this blog, we’ll talk about the differences between concrete and plastic septic tanks and tell you exactly why concrete is better.

Keep reading or give us a call on 02 6632 2978 to get a quote!


The main different between a concrete and plastic septic tank is, yep, you guessed it—material. And although plastic septic tanks are popular and have their importance, we believe concrete is the better choice for our clients.

For starters, plastic septic tanks are lightweight and resistant to corrosion. However, because they’re lightweight, plastic septic tanks are more likely to be damaged during the installation as opposed to concrete. First point to concrete.

Secondly, concrete septic tanks have higher effluent levels than plastic tanks. Not only that, plastic septic tanks, if not installed correctly, have been known to ‘float’ to the ground’s surface. Concrete septic tanks on the other hand, because of their weightiness, will not float to the surface. Second point to concrete.


Now that we’ve compared some of the key differences between concrete and plastic septic tanks, let’s look at the key benefits of choosing concrete for your home. At Graham’s Precast Concrete Products, we choose concrete, not just because it’s part of our wheelhouse—we also believe it’s the best material to use.

The advantages of choosing a concrete septic tank includes:

Each septic tank that Graham’s Precast Concrete Products supplies is constructed in accordance with Australian and NZ industry standards (1546.1.2 2008 Part 1). When it comes to wastewater treatment, you need a septic system that’s dependable and reliable. And for that, we recommend the study, versatile material that is concrete. The ultimate wastewater treatment solution. Septic tanks are an important asset, which is why it’s vital you invest in the right material.


The options available to you when it comes to installing a new septic tank may surprise you. You may be unsure whether to go with a standard PVC or steel tank or maybe you want a concrete septic tank.

Septic tank customers often want to know that their tank will last for a long time and function efficiently without causing them many problems. Concrete septic tanks have this advantage, making them one of the most popular. Although plastic tanks may seem less expensive, they’re probably not best for the long term, and that’s why concrete septic tanks offer so many advantages, including:

Built Tougher

Concrete Septic Tanks Are Weighted
Rust Free & Long-lasting
No Risk Of Collapse
Higher Effluent Capacity
Easy Installation

The health of your home depends on having the right septic tank. You need wastewater systems to ensure that wastewater is safely and effectively removed from your home. Graham’s Precast Concrete Products manufacture the best concrete septic tanks in Queensland. We are passionate about providing outstanding customer service and the highest quality tanks. Having built and maintained an impeccable reputation for over 40 years, Graham’s Precast Concrete Products is a proudly Australian company.

Our concrete products are of excellent quality, and our customer service is even better. The plumber can hook up our septic tanks right on the job site after delivering them. So, you can rest assured your wastewater is being properly managed, we can even help you install reed beds for additional filtration. You just need to coordinate the dates with your plumber, and we’ll install the tank when they arrive.

Get in touch with Graham’s Precast Concrete Products by calling 02 6632 2978 or online enquiry form today for a free, no-obligation quote. For more information on septic tanks and other precast concrete products, read our blog on the Advantages of Precast Concrete.