The day after I posted about our container garden, our friend Maier warned us about using recycled water. Some “gray” water is safe for the garden, but not all. I found this Australian government website containing the following guidelines:
‘Black water’ is water that has come in contact with toilet wastes. Black water has to be chemically treated and disinfected before it can be reused. General cautions include:
* Never use water that has come in contact with the toilet, or any other toileting fixture such as a bidet or urinal.
* Don’t use water that has been used to wash soiled nappies – this is also considered black water.
* Don’t reuse the water when you wash domestic pets, because of the high level of bacterial contamination.
* Don’t use grey water from the kitchen, as this can be contaminated with grease, bacteria and chemicals.
Common contaminants in grey water
If it is not used properly, grey water can make the householders ill and kill off the plants you are trying to care for. Some of the common contaminants in grey water include:
* Food materials* Household detergents, soaps and chemicals
* Bacteria and other disease-causing microbes.
Health risk comparison:
The health risks to you and your family depend on how you use grey water. Examples include:
* Laundry rinse water is low risk, while grey water from the kitchen is high risk.
* Sub-surface irrigation pipes are low risk, while hosing the garden with grey water is high risk.
* Using grey water on ornamental plants is low risk, while using it on vegetable gardens is high risk.
I’m not sure why laundry detergent is considered less of a problem than dishwashing detergent. If you plan to use gray water for plants I recommend reading all of the guidelines at the site.
When I told my son not to water with kitchen water, he was distraught. “You mean we killed them already?” He needn’t worry, as the first pea plant has sprouted.
Speaking of the environment, a revised version of my post on traffic circles appeared at the environmental blog Green Prophet.