What is greywater, how can we clean it, and what can we do with it?

Many people have been asking me about my greywater filtration system because cleaning our wastewater is not something our society is very familiar with. Most Australians understand the benefits of rainwater harvesting, and rainwater tanks are becoming more popular every day. Sadly, people often overlook a rainwater system’s counterpart: a greywater treatment and reuse system. By installing the Gator Pro Greywater Unit in my backyard, I’m not only reducing my wastewater but I’m effectively increasing my rainwater storage capacity by reusing the treated greywater to flush my toilets, wash my clothes and water my lawn – potable, rainwater is only used for sinks and showers. We don’t flush drinking water down the toilet at my house!

What is greywater?

Greywater is the relatively clean wastewater from showers, sinks and washing machines. Blackwater is water that has been mixed with toilet waste and requires a much more sophisticated system (including biological or chemical treatment and disinfection) before reuse. Because of the potential for contamination by pathogens and grease, water from kitchens and dishwashers is usually considered blackwater as well.  I hope to install a blackwater treatment system at my house when an appropriate technology becomes available given my space constraints.

How can we clean it?

For $1,940, I purchased The Grey Water Gator Pro, a device specifically designed for greywater treatment and reuse from the laundry, sink and shower wastewater. This system has already been approved in NSW, Victoria, SA, NT, WA and Qld, so I did not have to get specific approval from Council. However, in accordance with regulations AS/NZ 3500.2 it had to be installed by a licensed plumber. The Gator Pro cleans the greywater with a series of filters, and it requires minimal maintenance; filters should be replaced every 4 to 6 months. It’s about the size of a couple of eskies.

 My greywater system - The Grey Water Gator Pro

My greywater system - The Grey Water Gator Pro

What can we do with it?

Once my house’s greywater has been filtered, it is ideal for garden watering, toilet flushing and clothes washing – all significant, non-potable water needs. I can safely water my garden with it and easily pump it back into the house to flush toilets and wash my clothes. As I mentioned at the beginning of this post, reusing my greywater effectively doubles the capacity of my rainwater tank because I am saving that clean rainwater for potable uses only; according to Sydney Water, "approximately 61 per cent of the total wastewater produced by an average household can be used as greywater.”

I’d like to see every house in Australia have a rainwater tank, every house can maximise its investment in clean, rainwater storage by installing a wastewater treatment system. Water is a precious resource, and since when do we flush precious resources down the toilet?