Rainwater is a great alternative and free resource. By collecting and using rainwater when possible, demand on council’s water supply is reduced and the cost of your water bill goes down. You can use rainwater for:
- watering your garden
- washing your car
- supplying your washing machine and toilet
- topping up spas and swimming pools.
If you want to install a rainwater tank you need to decide whether you want to collect rainwater for outdoor use only, or to plumb it to the house to use as non-drinking water. This will determine the size of your tank.
For outdoor use, you may only need a barrel or a small tank, which is easy to install. You can learn how to do it from workshops organised by environment trusts. Simple barrels start at 200 litres.
For indoor use, you will need a bigger tank. Think ahead about the plumbing, backflow prevention and applying for consents. If the tank is plumbed into your house for indoor use you will need a building consent. Resource consents may be required for tanks used for indoor and/or outdoor use. We are currently reviewing consenting rules with the aim of publishing guidance on consenting requirements prior to next summer.
This is more effort than for a barrel, but your reward will be in higher water savings. Most domestic-use tanks are 3000 to 5000 litres. If you’re aiming for self-sufficiency, your tank should be at least 20,000 to 25,000 litres.
We support the installation of rainwater tanks but they are currently not mandatory as part of new development across the city. We are currently reviewing our stance on rainwater tanks and will update the community on the outcomes in late 2022.