05.Choosing and installing a tank
There are plenty of good reasons to install a rainwater tank, even in areas that aren’t drought-affected. You will:
- Reduce your consumption of mains water and save money in the long run.
- Reduce stormwater runoff into drains, rivers and oceans.
- Harvest clean rainwater, which can be better than mains water for your plants and appliances, as it’s less salty. Many people think rainwater tastes better than mains water and makes a better cup of tea, too.
The key points for choosing and installing a tank are below. For more details, see our free buying guide to rainwater tanks.
Choosing a tank
There’s a wide range of sizes, shapes and even colours to choose from; talk to a few tank suppliers and shop around for a good price. If you’ve got limited space, a slimline tank at the side of your house can be a good option. Others include underfloor bladders and modular tanks.
As a general rule, bigger is better: you’ll be able to harvest more water when it rains, have more available for the dry times, and often you’ll get a better rebate too. Sydney Water recommends a minimum size of 2000L for basic usage such as a toilet connection or garden watering, and at least 5000L for tanks supplying water to both the toilet and washing machine.
Even with a 5000L tank, you’ll probably still be reliant on mains water, as a typical four-person household uses around 7000L of water per week.
Once you’ve chosen a tank, you’ll need to prepare the site. Choose a location out of direct sunlight if possible, to reduce evaporation from the inspection holes. You’ll usually need a concrete slab or a tank stand for the tank to sit on, and if you’re connecting it to your bathroom or laundry, you’ll need a plumber.
Installing a tank
First, check with your local council and mains water supplier for any rules and regulations that apply to rainwater tanks in your area. You might need a building application, or there might be restrictions on the size and location of the tank. Pumps might have to conform to noise regulations.
Also check whether you’re eligible for any rebates or other cost savings. Most states and some city councils offer rebates for installing a rainwater tank, but conditions apply. For example, in NSW the tank must be at least 2000 L in capacity to qualify for a rebate, and additional rebates apply if you connect the tank to your toilet or washing machine.
Your roof and gutters might be a consideration, especially if you plan to drink the rainwater. Older painted roofs might contain lead. If you live in an area with heavy traffic or industry, the roof might collect a lot of pollution. Make sure your gutters have guards to stop leaves and other matter getting into the collected water, and consider installing a first flush device to stop the initial run-off (which is likely to contain roof contaminants) from entering the tank.