What is the Tankulator?

The Tankulator is an online rain harvesting calculator that can help you plan for a new rainwater tank or improve the performance of an existing tank. The Tankulator has been developed by the Renew Australia, Australia’s leading not-for-profit organisation promoting sustainable solutions for the home.

Click on the Get Started button, fill out the online questionnaire then click on the Get Tankulating button. An interactive graph will appear that will display your calculations.

Once the calculation is complete, you can compare different scenarios to find the best match for your circumstances. Will you run out of rainwater in a dry year if you live in Canberra and plumb a 10,000 litre tank to your toilet and laundry?

Get started

Buying a rainwater tank?

Tank Materials

Compare the cost, environmental impact, life span and other specs of different types of tank materials. Hear what Renew Australia members say about the tanks they have chosen.

Tank Siting and Installation

What will fit on your property and where to put it? Pros and cons of different approaches to placement and installation of your tanks.

Tank Filtration

What kind of filtration do you need on your system? What degree of maintenance are you willing to undertake?


Most rainwater systems will need a pump; what do you need to know? Also, pumps can use a lot of energy but there are ways to design your pumping system to reduce energy use.

Who are we?

The Tankulator has been developed by the Renew Australia, www.renew.org.au, Australia’s leading not-for-profit organisation promoting sustainable solutions for the home.

Renew Australia is Australia’s leading independent organisation promoting sustainable solutions for households. A not-for-profit Renew Australia provides independent, practical advice on how to make homes cheaper to run, more comfortable to live in and environmentally-friendly.

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Advice and Experiences of Renew Australia Members

Don't skimp on the size of the tank. It's better to have too much tank capacity than see water go to waste during prolonged rainy periods. The incremental cost of increasing tank size is a small percentage of the total cost. – John, VIC

Get expert advice if you are doing it yourself or use a company that can demonstrate experience and expertise in tank installation. – Roger, SA

Build a stone enclosure around tanks for bushfire protection. – Peter, NSW

Consider a pressure tank - they're quiet and don't need to pump every time you turn a tap on. – Sophie, VIC

Our rainwater tanks are in the garage and in the event of a deluge there can be an overflow. I have a number of friends who have similar arrangements with similar problems. Conventional plumbing doesn't seem to cope with rainwater tanks in locations that can flood. – Andrew, NSW

Be sure you can maximise the use of the water you harvest. – Lindsay, QLD

Design the tanks in from the start of the house design process. – Russell, NSW

More roof area added to the collection area because the drought is tough… – David, WA

Make sure that there is adequate foundation support for the tanks. Mine were placed on flat sandy soil, but one started to tilt dangerously towards the fence after about a year. – Henry, VIC

Research first, find a good plumber who sees the advantage of tanks, don't rush the process. – David, NSW

DO IT!!! – Daryl, QLD

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