Everything you need to know about buying rainwater tanks

Save money. Save water. Install a rainwater tank.

With Australia being the driest inhabited continent on earth, it makes good sense to install a rainwater tank at your home. But before you rush out to buy a new tank, there are a few questions you need to ask to ensure you purchase the right tank for your household.


What size water tank do I need?

Rainwater tanks come in all shapes and sizes, from round and large to slimline water tanks for smaller areas. The size of your tank will vary depending on your usage needs and the amount of rainfall in your area. When calculating which rainwater tank size is best for your needs, consider the following.


What do you intend to use your rainwater for?

Consider what portion of your water usage will come from rainwater. Will it be used only for gardens or for the toilets and the washing machine too? Do you aim to run your entire house from rainwater, including your showers and drinking water?


What capacity do you need?

Consider the size of your house and garden, the number of people at home each day and how often everyone showers, runs the dishwasher or washing machine.

One of the easiest ways to estimate your water consumption is to check your water bills. These often include information about average usage in your area. Your state water authority may also provide rainwater harvesting tank size calculation tools.


How much rainwater can you collect?

Once you know how much water you’re likely to need, the next step in calculating an appropriate water tank size is to work out how much rainwater you can collect.

1mm of rainfall on 1m2 of roof area = 1L of rainwater

That means if your roof area is 250m2, 5mm of rain = 1,250L of water.

You’ll also need to consider the average rainfall in your area and rainfall patterns. If you have very wet winters and long, dry summers, your water storage needs will be different from a household in an area with more regular rainfall that will top up tanks across summer.

These calculations should give you a fair idea about what size rainwater tank you’ll need.


Rain water draining into gutters


What should my rainwater tank be made from?

Large or small, rainwater tanks come in a range of materials to complement your home and garden.


Steel rainwater tanks

A steel rainwater tank is a great choice if you want to match your tank with a Colorbond roof. Many come with liners which help protect both the quality of your drinking water and your tank from corrosion. Steel water tanks can be constructed in a number of shapes from large and round, to slimline versions, perfect for smaller yards.


Poly rainwater tanks

Light and flexible, these plastic rainwater tanks can also be moulded into a huge variety of shapes in many colours. Most Australian made rainwater tanks are fabricated to be UV resistant and fade-resistant for lasting durability. With minimum maintenance required, poly tanks are a great budget-friendly choice


Concrete rainwater tanks

Concrete water tanks can be a great choice for water storage as this natural material is a fantastic insulator and can even help reduce the acidity of your water. If you’re building a new home, you can blend the tank into the house design, or create an underground rainwater tank to maximise your yard space.


Black Rain water tank installed in a suburban house


How much does rainwater tank installation cost?

When determining your new rainwater tank costs, don’t forget to consider delivery and installation fees. Depending on the size, location and material of your tank, there will be a range of factors that influence your final outlay.

Will you need extensive site preparation? This will be the cost to prepare the site and form a solid base for your tank.

If your tank will be connected to toilets, showers or appliances in your home, you must use a licensed plumber. There may also be additional costs for pipes, taps, a suitable water pump, first-flush devices, and other necessary fittings.

Now is the perfect time to be purchasing and installing a rainwater tank while winter rains are still falling! Talk to Chiswick Plumbing about connecting a rainwater tank to your home.