What is greywater?
It is the waste water that comes from our washing machine and laundry tub, and our showers, baths and hand basins. It does not include water from the toilet or other sewage water, including water used to wash cloth nappies. Kitchen water is technically grey water but is generally not recommended for re-use in the garden, because of the high concentrations of food waste and, usually, chemicals.
How can you use grey water?
Different areas have different rules about the reuse of grey water, however a good rule of thumb is to only collect what you can use immediately unless you have an approved grey water treatment system installed. In some areas grey water irrigations systems must distribute the water under the soil.
You can collect grey water by keeping a bucket in the shower to pour onto the garden afterwards or to use for flushing the toilet, or you can divert the water directly from your washing machine hose.
Some general Dos and Don’ts for using grey water
- Only use as much water as the soil can absorb at any given time.
- Wash your hands after using grey water.
- Stop collecting or diverting grey water when during wet times.
- Stop using grey water if you notice any odours developing, or if plant look unwell.
- Use grey water friendly laundry detergents and shower products.
- Use your grey water as soon as possible after collection.
- Rotate the areas of the garden on which you use your grey water.
- Check out the regulations in your area (if you are in Australia, see the links at the end of the article for more information).
- Don’t use grey water on vegetables that will be eaten raw.
- Don’t use any grey water with faecal contamination, including from washing or soaking cloth nappies.
- Don’t use grey water in a pond or pool.
- Don’t use kitchen water (except overflow from running water until it’s hot, which you can collect in a bucket).
- Don’t store grey water for more than 24 hours without treating it.
- Don’t let anyone drink grey water, including pets.
- Don’t let grey water run off your property.
- Don’t use grey water when members of the household are unwell.
Resources – Australian Regulations
- National: http://www.nwc.gov.au/www/html/914-waterlines-10.asp?intSiteID=1 – National Water Commission, Requirements for the installation of rainwater and greywater systems in Australia
- ACT: http://health.act.gov.au/publications/fact-sheets/greywater-use – Grey Water Use – Guidelines for Residential Properties in Canberra; http://www.thinkwater.act.gov.au/water _savingtips/Greywater_faqs.shtml – Greywater – frequently asked questions
- NSW: http://www.waterforlife.nsw.gov.au/recycling/greywater – contains link to PDF: NSW Guidelines for Greywater Reuse in Sewered, Single Household Residential Premises
- NT: http://www.nt.gov.au/nreta/water/wise/factsheets.html – NT Waterwise Factsheets, including one on Greywater Reuse
- QLD: http://www.dpi.qld.gov.au/26_16147.htm – Gardening with greywater – water quality; http://www.derm.qld.gov.au/water/regulation/recycling/greywater.html
- SA: http://www.dh.sa.gov.au/pehs/branches/wastewater/alternative-onsite-systems.htm – Greywater & other Alternative Onsite Wastewater Systems
- TAS: http://www.environment.tas.gov.au/index.aspx?base=106 – Environmental Guidelines for the Use of Recycled Water in Tasmania
- VIC: http://www.epa.vic.gov.au/water/reuse/reuse.asp – Household greywater reuse