Plants don’t need perfectly clean water; you can use household wastewater (called greywater) in your garden - with some precautions.
What is greywater?
Greywater is any lightly used water that has been left over from use in the home - from the shower, bath, sink, laundry.
Water from the toilet is referred to as blackwater and should only ever enter the sewerage system.
Household soaps and detergents are harmless to plants, but water containing bleach or disinfectant, dishwasher salt and stronger cleaning products should not be used as these can harm plants and damage soil structure.
Using greywater in the garden means you’re reducing demand for the treated drinking water that comes from your taps. In decreasing your overall water consumption you're cutting your bills too.
Useful tips
- Don’t use water from kitchen sinks as this could contain grease and food particles – only use water from bathroom sinks.
- If plants are watered entirely with greywater during a long dry spell, there’s a possibility that dissolved substances will build up in soil and affect plant growth. These will drain from the soil once there is a rain shower, or if you alternate watering with stored rainwater.
- Greywater should not be stored but used immediately to prevent harmful organisms from multiplying and causing smells.
- Use mild, eco-friendly soaps.
- Don’t use greywater on salads or produce that’s eaten without cooking. Use it only on ornamental plants, lawns and established trees.
- Make sure any water has cooled completely.
- Don’t pour greywater straight on foliage, only on the soil around plants.
