Polymaster ST3100 Septic Tank

12 Things to Consider When Buying a Septic Tank

12 Things to Consider When Buying a Septic Tank

Septic tanks are a necessary and key component for septic systems. A septic tank is a watertight container, buried in the ground near the house, that holds all of the wastewater from toilets and other sources within a septic system. The septic tank has two main jobs: to store sewage until it can be pumped out of the septic system, and to isolate solid waste from the liquid sewage so that is does not clog up pipes or seep into groundwater. There are a few things you should consider when shopping for a septic tank; this blog will discuss 12 points that may help you find the best septic tank.

1. Is a Septic tank needed?

Our major cities and townships include wastewater services that are paid for in our rates. Septic tanks are installed on properties where there are no waste water services available on the property or by the municipality. This is mostly in rural areas, or properties just outside major regional centres where council have not yet expanded their infrastructure and services. A septic tank is required to handle all waste produced on a property where there are no council provided services.

2. Types of Septic Tanks

Septic tanks are available in a variety of sizes and capacities, and there are two different types of septic tanks. The first type is a passive septic tank. This system will only hold and separate solid waste and allow liquid sewage to run out into subsurface irrigation or run out into a paddock. The solid waste is pumped out by a truck when it is full. The second system is an Aerated Wastewater Treatment Plant, also known as an AWTS system or a treatment plant. These systems are far more complex, that have aerating pads, pumps, chlorine or dosing tablets and bacteria. They generally don’t require to be emptied by trucks for years as the bacteria breaks down the waste, and the waste water pumped out is much cleaner and better quality than normal passive septic tanks.

3. Septic Tank Selection

Your local council will determine which system needs to be installed on your property. As a country, Australia is moving toward AWTS systems, but your local municipality has the final say over your septic tank requirement. If your council have elected that you require a passive septic tank on your property, you can elect to install an AWTS system with your councils approval. This is however not the same in reverse. In our experience, it has not been possible to overturn a council where they have requested an AWTS system to be replaced by a passive septic tank.

4. Cost Differences

AWTS systems are considered by all in the industry to be industry best solutions. Like anything good, they are more costly and do require mandatory maintenance programs set out by the Department of Health. This is to ensure your health and also the health of the system and ensuring the bacteria in the tank is working effectively and that either the chlorine or dosing tablets are topped up. The technicians will also check your aeration pads and pump systems and timers to ensure it is working as intended. Passive septic tanks are much simpler. They are a set and forget system. For most installations, there is little to no maintenance required and other than getting a truck to empty it every few years, require very little else. The tanks are considerably cheaper to buy and install with less moving parts, and less to go wrong.

5. Tank Capacity

Most people require a 3000 litre septic tank. The volume of the septic tank is again determined for the most part by councils and across Australia we have seen that the most common size is our Polymaster 3100 litre septic tank. A 3100 Litre septic tank is suitable for a 1-5 person domestic home. a 4500 litre septic tank is suitable for a 6-10 person home. We also do commercial septic tanks that are far more specialized and the septic tank sizes can go up to 25,000 Litres.

6. Plastic vs Concrete

Today plastic septic tanks dominate the market. They are far cheaper to manufacture, last longer and much easier to install. The delivery costs are also much cheaper and they can travel long distances fairly economically compared to concrete tanks. On average concrete tanks only lasted around 10 years, whereas plastic septic tanks will last twenty to thirty years. Unlike concrete septic tanks, plastic tanks are not porous and so you will not get seepage of waste water into your ground water or around your garden. For all these reasons, and more plastic septic tanks have become the industry standard today.


7. Septic Tank Installation

Septic tanks cannot be installed by private individuals and must be installed by licensed plumbers. Upon installation, the septic tanks are registered by your plumber with your local council or municipality who sign off on the installation. Passive septic tank installations are fairly straight forward that have two pipes. One for the waste water to enter into, and one for the water sewage to exit out of. They are very easy to install and most civil plumbers will be very experienced in their installation. AWTS systems are more specific and we highly recommend specialized plumbers and civil earth workers to install them. Having an in depth knowledge of the AWTS systems and their installation requirements will be the difference between a good installation and a bad installation.

8. Emptying a Septic Tank

At some point your septic tank will need to be emptied. This falls on the homeowner’s responsibility. On average, we have seen a normal domestic home with a 3100LT septic tank needs to be emptied every three to five years. Of course a number of factors determines this including:

a) number of people in the household

b) capacity of the septic tank

c) type of septic system installed

If your tank has not filled up after six plus years, we still recommend getting your system pumped out. Over long periods. you will develop septage, (the solids that settle in the bottom of the tank) which begin to contain harmful bacteria or chemicals.

Other signs that you need to empty your septic tank include:

  • Water Pooling around your septic tank or in your paddocks
  • Slow drainage of your waste water pipes and system
  • Foul odours in the property and around your property
  • An overly healthy lawn around the tank (I know, crazy right)
  • Sewer backup
  • Gurgling pipes both when the system is active and when it is not.
  • Trouble flushing your toilets

9. Where does kitchen water and shower water go?

On a property with a septic tank, the entire home is connected to your septic tank. This includes the toilets, showers, bathroom sinks, kitchen sinks, laundry and any other service connected in the home. You also need to connect outdoor swimming pools and spas, as they have chemicals in them through to your septic tank.

The only part of the house that is generally not connected is the downpipes from your roof. These are normally sent to your legal point of discharge (LPD) or your property or otherwise towards a dam or river on your rural block. We recommend speaking to your council or plumber for confirmation.

10. Tank Inspection and Service

Your septic tank needs to be inspected and serviced by a professional. Dealing with human waste is hazardous to your health and requires professional licensed plumbers. You should never enter a septic tank. It is a confined space and an extreme health risk not only to you but to anyone that attempts to rescue you should the toxins and chemical make you pass out.

11. Difference between Polymaster & Graf Septic Tanks

ASC Water Tanks sell two brands of septic tanks. They are Polymaster Septic tanks and Graf Wastewater Septic tanks. Both systems are extremely good and both are seen to be industry leaders in the passive septic tank market. Polymaster are a Victorian based manufacturer who ship only into Victoria, southern New South Wales, the ACT and into certain parts of South Australia. Graf systems are available into Victoria only.

Polymaster only have two sizes, whereas Graf have three sizes. That said, Polymaster have our most popular septic tank size at 3100 Litre. The Polymaster also requires a shallower excavation at 1665mm high, which can save you a lot of money. Both systems come with lifting points to be able to easily pick them up with machinery onsite and place into your hole.

12. Where can I buy an Aerated Wastewater Treatment Plant (AWTS) system?

ASC Water Tanks does sell AWTS systems. We supply and delivery the Kingspan BioFicient Advanced Domestic Treatment Plant. These are made from a fibre reinforced plastic (FRP), and come from Europe. They are certified to all required Australian Standards for AWTS system. For assistance on AWTS please call and speak to one of our product specialists.

Kingspan Bioficient Domestic Aerated Treatment Wastewater System. AWTS

Suitable for homes with up to 8 people, the BioFicient® Advanced is manufactured from high quality Fibre Reinforced Plastic (FRP) and uses the latest treatment technology to deliver a high quality of water discharge.

With a high performance, low power consumption treatment technology, coupled with minimal maintenance requirement, the Domestic BioFicient®  Advanced wastewater treatment plant will provide large homes with a reliable and effective solution for many years to come.

  • ​Certified to AS 1546.3:2017 (Why is it important?)
  • ​Certified to AS/NZS 1546.1:2008
  • 65 years experience in wastewater treatment solutions

ASC Water Tanks have been supplying Australian homes with rainwater tanks and pumps since 2007. We sell top-grade Australian Made water tanks to support our economy and to deliver a superior product to our customers and have industry experts able to assist in your next project.

To discuss your next water pump set up for your rainwater harvesting system at home or irrigation system, contact us here or give us a call on 03 8795 7715.

Article By: Anant Yuvarajah (Director)

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