Greywater and rainwater are two terms that are often heard amongst the eco-conscious in regard to DIY water conservation and use. Collecting rainwater and sing greywater are some of the simplest ways to make use of every last drop of water. It’s however important to understand that both greywater and rainwater are very different and so are their applications.


What’s the difference?

Greywater is water that is discharged from showers, bathroom sinks, tubs and washing machines. As long as homeowners use greywater safe products, greywater is safe for irrigation use. The reason why water discharged from toilets and kitchen sinks is not mentioned is because it is black water due to the immense bacterial load. On the other hand, rainwater is naturally pure and is free of minerals, chemicals and salts. And while rainwater accumulates organic matter from roofs, it is great for irrigation of plants.

Irrigation with greywater vs. rainwater

Due to natural clean nature of rainwater, it can be stored for as long as a homeowner desires before using it for irrigation. The water is highly filtered on the way to barrels, cisterns, and tanks to ensure that anything that cause clogs or growth is removed. Rainwater is used by most people to water potted plants that are extremely sensitive to chemical and salt buildup. On the other hand, greywater works best when released directly to the landscape, about two inches below the surface. There are greywater systems that are purposely designed to control the rate of distribution and automatic pumps that ensure water is recycled regularly to prevent it from turning into black water.



While most people prefer to collect greywater from shower drains and sink drains, it’s important to understand that greywater systems require permits and professionals to install.

Incorporating greywater in a garden

If you are thinking of incorporating greywater in your garden, congratulations. Greywater is suited to a wide variety of plants and can be used to increase water supply that the plants in your garden direly need. There are several ways of incorporating greywater in your garden like directing it to a greywater system that vents it and discharges it in your garden soil.

Both greywater and rainwater are very useful when it comes to irrigation and other uses that require increased water supply. You shouldn’t however combine them unless with the help of a professional. To learn more about greywater and its uses, enter regenerative leadership institute.