Q. I had water restrictions due to the drought and converted my washing machine so that I could use the gray water to water my trees. I also got the water from my sink and from my shower to use it. Will using this water on my trees harm them?
A. When trees are in extreme drought, any water is better than no water. However, some detergents, shampoos, and soaps can contain excess salts or chemicals that can harm the soil biome and your plants.
When using gray water, you want to select the correct detergents and cleaning products to avoid damaging the environment and the landscaping of plants and trees.
The University of California publication “Use of Gray Water in Urban Landscapes in California” Advises avoiding powder detergents and chlorine-based bleaches in your wash.
Since gray water can potentially harm the environment, humans, and pets, you need to make sure the pipe drains onto a thick layer of mulch to prevent runoff.
Another problem with using gray water in laundry is the back pressure on the washing machine pump. To minimize this, be sure to use a large diameter pipe that contains multiple openings.
Collecting water in a bucket or pitcher in the shower or at the sink while you wait for hot water is an easy way to save water. Because it is pure water, it can be used to water any plant without worry.
However, if your indoor system uses a water softener, be aware that some systems can add a lot of salts to the water during the water purification process. Over time, this can damage the slope of the soil, making it difficult for roots and water to penetrate.
Use of gray water from a washing machine, shower, or bathtub and bathroom sink is permitted in California, but gray water from the kitchen sink and dishwasher is not permitted. are not. This is due to the potential for food waste containing harmful pathogens.
Gray water is not recommended for irrigation of vegetables, which could be contaminated with harmful compounds, chemicals or pathogens present in the water.
For more information on greywater systems and designing and configuring your own system, read the University of California greywater information at https://bit.ly/3DhQpfJ.
This post also has good information on a tree’s weekly irrigation needs based on the size of its canopy. This is useful even for those who don’t have a gray water system and are just trying to conserve water without damaging their landscaped trees. For example, a tree with a 100 square foot canopy that has average water requirements, which are the majority of trees in our landscapes, requires 62 gallons per week in our indoor summer climate.
The Shasta Master Gardeners program can be contacted by phone at 242-2219 or by email at firstname.lastname@example.org. The Gardener’s Office is made up of volunteers trained by the University of California to answer gardeners’ questions using information based on scientific research.