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Home » Water Tanks » How To Install A Rainwater Tank: A Video Guide

How To Install A Rainwater Tank: A Video Guide

Here’s a fact for you – 1 in 4 houses in Australia has a rainwater tank and pump setup. That’s right, and for good reason. Not only does the tank provide you with free surplus water, but it also helps to conserve water.

However, the installation process is not so simple. To start with, the process of rainwater tank installation needs should be as per the guidelines set by the state government. The installation may also need approval from a regulatory authority.

So, you need to know the basic guidelines before you plan for an installation. Here, we will take a look at some practical tips and suggestions to help you with the installation process.

Rainwater Tank Installation: The Options 

Let’s consider the various types of rainwater tank installations and take a closer look at each process.

Assuming you have already sized the tank based on the rainwater performance and your water demand, here are a few quick pointers for all installations.

  • Make sure that you provide the rainwater for the fixtures and appliances at their rated pressure. Ideally, you should install the tank at the highest position possible. That will reduce the capacity of the pump required for delivery. However, you will also need to connect it with the downpipe from the roof guttering.
  • Use a top-grade tank and durable water tank accessories and components to prevent failure and leakages.
  • The tank should not rest on the existing foundation of a building.
  • There should be sufficient space for accessing the components for maintenance needs.

1. Freestanding Tank

A freestanding tank will need a solid foundation on level ground. However, with smaller tanks, you can also use a tank stand. This reduces the installation cost as you need not use a pump and can refill watering cans or buckets directly from the tank outlet.

When it comes to the choice of material for the foundation, there are options like concrete, gravel, or crusher dust. However, concrete is the most stable and long-lasting choice. On the downside, if you aren’t used to working with concrete, you’ll need to hire a professional.

No matter the material you choose, the ground needs to be compacted to prepare a level surface. This will ensure that the pressure of the tank is uniform across the entire foundation.

A concrete foundation should be 75 to 100 mm thick depending on the size of the tank. For a larger tank, you can raise the thickness to 150 mm. To make the concrete last longer, use rebar or mesh while pouring it. 

Gravel or pea gravel is also a popular choice as it is less expensive and retains shape more effectively. Once the compaction is complete, you can build a concrete curb wall around the space to hold the gravel. Then add some sand with the pea gravel to ensure better packing.

2. Slimline Water Tank

Slimline water tanks come with a narrow profile that allows homeowners to store a large volume of water within a small footprint. This is the reason for its popularity in urban areas with space shortages. If you don’t have enough space for a round tank, slim tanks are the best option.

The following are a few pros and cons of slimline rainwater tanks:


  • Slimline water tanks are a space saving option.
  • They have a unique look and a contemporary feel
  • They can be customized to suit your requirements


  • A higher price tag
  • Not available in high capacities
  • They are not self-supporting like round tanks

The installation of s slimline tank is usually done as per the guidelines provided by the tank manufacturer. As expected, preparing a level concrete base is necessary for freestanding tanks. Quite often, floor brackets are used to secure slimline tanks from toppling.

3. Underground Tank 

Many rainwater harvesting systems use underground tanks or bladder tanks as the tank does not take up space at the ground level. The low profile design not only saves real estate space, but also protects the tank from weather damage.

Here are a few pros and cons of underground tanks.


  • Saves space for landscaping and driveways
  • Keeps the water dark, which prevents algae growth
  • Water temperature remains steady irrespective of weather conditions


  • Installation of the tank is expensive and takes time
  • Inspecting the tank for cracks or damages is difficult
  • Underground tanks are not suitable for all soil types

Installing an underground rainwater tank setup is best done by a professional. It involves multiple steps like excavating the ground, base preparation, installing the tank, and backfilling. We won’t suggest that you handle the process without the necessary equipment.

Rainwater Tank Pump Setup

Water from a rainwater tank setup needs to be delivered through a pump to generate the required pressure. Selecting the right pump is an important step and the two important parameters are the pump flow rate and the total dynamic head required.

The pipework can be above ground or underground based on your requirements. In addition, the plumbing system should include first flush diverters and overflow management connections. 

If you are using the rainwater for non-drinking purposes, an interconnection with the drinking water supply is suggested. This should come with a backflow prevention system to prevent contamination of the main supply.

Ideally, you should use stainless steel and brass fittings that will resist corrosion for longer periods. The pipes and fittings should be chosen as per the guidelines in AS/NZS 4020:2018. 

When is the Best Time to Install My Tank? 

Due to the wide range of climatic conditions in Australia, choosing the right time for a rainwater tank installation can be tricky. However, spring is the best time for outdoor work as the weather remains pleasant. Besides, there are fewer chances of the work getting interrupted by sudden showers.

How Should I Maintain My Rainwater Tank?

Maintaining a rainwater tank is not difficult. Here are some important steps you need to take.

  • Keep the gutter and roof clean. Keep the gutter mesh free from any damage.
  • Clean all screens and filters at regular intervals.
  • Service the pump as per the manufacturer’s recommendations.
  • Check the tank for structural damage or corrosion every year.
  • Prevent sludge build-up inside the tank and clean it once every 2 to 3 years.

Rainwater Harvesting Case Studies

In most urban centers in Australia, the water utilization is based on a combination of rainwater and mains water supply. Studies have also suggested that efficient use of rainwater harvesting can reduce the load on utility water systems by almost 50%.

The rising popularity of rainwater tanks in Australia is an indication that it is being considered an integrated solution that offers various benefits to an urban system. Moreover, epidemiological evidence indicates that rainwater consumption does not increase the risk of gastrointestinal ailments either, although using rainwater for drinking or other potable household use requires the use of a whole house water filter.

Installing Rainwater Tanks (Video Series)

We’ve discovered a series of four video which cover a lot of the information that will help you decide what you want to achieve, which tank may be sest for you, which accessories will serve you best, and what is required for installation.

While we don’t agree with everything that is said, or the importance given to each issue, but we do believe it’s the best series of information on the subject on video.

Part 1: Rainwater Systems

Part 2: Collection

Part 3: Storage

Part 4: Supply


The need to save a precious natural resource like water is becoming more important with each day. That makes a rainwater tank installation a great way to move towards water sustainability.
Time for you to pick the right rainwater tank. But before that, make sure to take note of the regulations set by the local authorities.