Greywater is the wastewater from the bath, the shower, the bathroom sink and the washing machine. Reusing greywater can significantly reduce the amount of fresh water you use.
In Auckland, you can plumb a greywater recycling system to reuse water for flushing the toilet. This requires:
a small tank to store greywater for a short time
slight chlorine treatment to avoid build-up of harmful bacteria
a public water supply to the toilet as back-up if the tank is dry
a discharge from the tank to the sewer pipe.
Greywater tanks in Auckland require a building consent.
These systems are still rare in New Zealand, and you should expect questions on the safety of your project.
Before starting to design your system, we suggest you book a consultation with the Eco Design Advisor team at Auckland Council.