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We hear of it enough, but what is greywater, and how do you use it?

Garden hose

Conserve water in the garden by using greywater.

Credit: Wikimedia

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What exactly is greywater?

Greywater sits in the middle of the spectrum between white (fresh) and black (toilet and toxic waste) water. It's the type of wastewater you generate from household activities such a bathing and doing the laundry.

In a drought-affected, water-short country like Australia, recycling water is a way to stretch a limited resource. Greywater can be used to help maintain your garden (use it to water your plants and lawns so that fresh water isn't wasted), and treated greywater also has some limited uses inside the home.

What are the different ways of using greywater?

Greywater may be bucketed, diverted or treated.

Bucketing involves capturing small amounts of water in a bucket after use. For example, you may scoop out water from a bath to throw on the lawn or divvy up between pot plants outside.

Diversion of greywater is essentially an automated version of bucketing, where greywater is redirected outside (direct from the washing machine, for example), generally into sub-surface irrigation systems.

A greywater treatment system can be used to recycle water for use both outside and inside the home for things like doing the laundry and for flushing toilets.

Is greywater safe?

Any greywater you use may contain higher levels of chemicals and bacteria. So don't drink it, or let your pets drink it, and always wash your hands after using it.

But wastewater from showers, baths, hand basins and washing machines is perfectly safe to use on the garden - though keep in mind that you should use environmentally friendly products (soap, shampoo, detergents and the like), so that you don't harm your plants or the soil!

It's not a good idea to use kitchen wastewater, as soil organisms won't break down the food and chemical contaminants in the water very quickly.

Be sure to only use as much liquid as the soil can absorb, and rotate the areas you use the wastewater on. If the plants start to look unhealthy, or your garden begins to smell bad, then stop! And don't use wastewater on fruits or vegetables that you intend to eat raw.

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