Using Greywater for Home Gardening

Reviewed and Revised on 10/17/2013

What is greywater and how can it be used?

Greywater is the domestic wastewater from all sources except the toilets. As per the EPA wastewater sources can include water from:

  • laundry

  • shower/bath

  • washing machines

  • dishwasher

  • kitchen sinks

Greywater can be used for home gardening and landscape irrigation. This can have two major benefits.

  • It reduces the need for fresh water and hence is a great way to conserve water as well as energy. Large amounts of energy are used in intake, treatment and transportation of water to residential homes. All that energy gets conserved. 

  • Reuse of waste water which otherwise would have entered first the sewers and then the waste water treatment plants reduces the amount of water entering into these streams. This again prevents the energy, which would have otherwise been used in treatment, to be used and hence gets conserved.

Greywater should not be confused with Blackwater. The term Blackwater indicates wastewater from the toilets. 

Greywater does not need extensive treatment before reuse. It however needs to be used carefully as it contains contaminants such as grease, hair, detergents etc. and hence may not be suitable for all garden uses.Also, all greywater must be used within 24 hrs of its production. To utilize greywater in a household the home plumbing must have separate drains for blackwater and greywater sources, which is easier to do in new constructions than the existing ones. There are however a number of ways it can be achieved in the older homes.

In most states, the Department of Health regulates the installation and reuse of greywater and onsite systems. Details may also be found in your Building Code. It is also recommended to consult your local water authority or council for advice on greywater use regulations.

Additional information on greywater can be found here.