Is Grey Water Good for Plants? Here’s What You Should Know

Grey water refers to wastewater that’s been drained from your washing machines, showers, and sinks. It contains bits of grease, dirt, and food, making it look ‘dirty’ and ‘unsafe’. If you’re trying to grow plants from your garden, you may end up thinking twice about using it.

Grey water is generally safe for plants as long as you’re only using biodegradable products down your drain. Containing nutrients, it’s even been found to be beneficial to boosting plant growth.

To know more about grey water and its benefits to your garden, read on.

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How Can Grey Water Affect Plant Growth?
What Is the pH of Grey Water?
Does Grey Water Contain Chemicals?
Does Grey Water Contain Bacteria?
How To Use Grey Water System for Your Plants
     Bucket Method (Do-It-Yourself)
     Irrigation System
The Dos and Don’ts of Upcycling Grey Water For Your Garden
What Plants Are Best for Grey Water?

How Can Grey Water Affect Plant Growth?

How Can Grey Water Affect Plant Growth

As mentioned earlier, grey water can be beneficial to plant growth. It can even help boost crop yield and create a cooler micro-climate in your garden. With the use of grey water, you may need less fertilizers to help your plants grow.

How’s that possible?

Your garden can thrive with grey water for it’s abundant with micro-nutrients. It contains organic matter that is commonly used as fertilizers.

Take phosphorus and nitrogen as examples These nutrients are important for plant growth. When they are present in your garden, you can expect a boost in your crop production. 

When your garden is constantly flowing with water, you can also create a cool micro-climate. Additionally, it can facilitate the rapid growth of trees. These trees can offer shade, preventing the ground from being exposed to so much heat.

When the general garden climate is cool, plants can effectively perform photosynthesis. The condition can also prevent plant stress and dehydration. 

What Is the pH of Grey Water?

Grey water is alkaline and is expected to have a higher pH level than fresh water. If you worry about having acidic soil, using it might help.

Take note that while there are many garden plants that thrive in neutral or alkaline soil conditions, there are plants that don’t. Examples include blueberries and rhododendrons. Given this, you need to regularly check the pH level of your garden soil.

Does Grey Water Contain Chemicals?


Grey water contains chemicals. Since they come from washing machine water, dishwasher water, and bathroom sink water, the chemicals are mostly cleaning agents.

The chemicals used in most cleaning agents are organic. Organic matter contains carbon which will decompose in the soil and be converted to water and carbon dioxide. 

To avoid harming plant leaves, it is advisable to apply grey water on the soil and not directly on the plant itself or the edible portion of the plant.

Does Grey Water Contain Bacteria?

Yes, grey water contains bacteria. They generally come from the water used to wash out the soap from the human body or from the water from soiled human clothes.

Because of this, some people are showing concern that such bacteria that goes into the plant may return to humans when they eat the produce such as root crops.

In reality, the soil itself contains hundreds and thousands of bacteria, microbes, pathogens, and other living matter. For many years, many people have been pulling their food out of the soil and eating them raw.

How To Use Grey Water System for Your Plants

The main concerns for grey water containing harmful chemicals and bacteria are understandable. However, if the chemicals used are not toxic, grey water systems can be effective as a way to reuse water.

Reusable water or grey water can be used to water plants and crops in your gardens such as fruit trees and ornamental plants.

Using a grey water system aids in minimizing water supply wastage, minimizing home expenditures, and supporting a more sustainable and environment-friendly lifestyle.

Irrigating plants using grey water is perfectly safe if you are using biodegradable cleaning products that get washed out. If you are thinking of incorporating a grey water system to water your plants, there are two ways to do this – the bucket method and the irrigation system.

Bucket Method (Do-It-Yourself)

The bucket method may require a lot of work but it is the most cost-effective and low-maintenance way of reusing water. There are so many creative ways you can be creative as to how you collect your used household water.


For instance, you can use a small basin when washing your vegetables and transfer the used water to a big container beside your kitchen sink. You may also pour the water you used for boiling on the container and not let it go down the drain.

Irrigation System

If you have the financial resources and are planning to make grey water an essential part of your household, then you may consider going for a professional irrigation system. You can reach out to professionals in your area who can help you develop your irrigation plan for grey water codes.

If you don’t want to hire professionals to make the system for you, it is possible for you to do it yourself. The easiest way to do this is if you have a washing machine. With a washing machine, you don’t need to make major changes to your home plumbing system.

With the washing machine’s discharge hose, you can connect it to the irrigation tubing. In irrigating your plants, you should irrigate at the drip line or the outer edge of the branches. It is logical to do this because plant roots extend past their drip line.

If you are wondering how much water individual plants need to receive, provide only enough that it can saturate the soil. Though, doing the irrigation system on your own will require that you do extensive research and have the mechanical skills to use tools and materials.

The Dos and Don’ts of Upcycling Grey Water For Your Garden

The main reason why many people want to upcycle grey water is to address the water shortage. If you want to upcycle grey water, below are some of the things that you can and cannot do when using grey water.


  • Purchase biodegradable laundry products that have lower levels of sodium and boron
  • When using cleaning products, use small quantities as much as possible
  • Spread the grey water evenly around your garden
  • Apply grey water onto the ground and not directly on the root crops or edible plants
  • Plants need a break from grey water every six weeks by using tap water or rainwater 


  • Storage of grey water should not exceed 24 hours
  • Don’t use grey water to water your crops if someone in the household has a serious digestive problem or pathogenic infection.
  • When you wash diapers in the laundry machine
  • When your garden is along streams or swamps

What Plants Are Best for Grey Water?


While it is generally true that grey water is good for most plants, you still have to be careful because there are some plants that may not like it. You would need to do extensive research as to which crops or plants would thrive in grey water. 

The list below shows plants that thrive well with grey water.

  1. Bermuda grass
  2. Peach trees
  3. Black-eyed Susans
  4. Bird of paradise
  5. Melaleuca
  6. Dietes
  7. Gardenia
  8. Callistemon
  9. Conifers
  10. Liriope
  11. Yucca
  12. Hibiscus
  13. Manilla grass
  14. Seashore paspalum
  15. Saltwater couch grass 


You may not be so keen as to use grey water for your garden and that’s completely understandable. Using grey water could even be illegal in your country due to the imposition of state regulations. If using grey water is allowed in your location, you can easily collect and reuse water to overcome summer drought.

Living a more sustainable water culture and environment-friendly lifestyle can be beneficial in these pressing times, especially when there is a shortage of clean water. It is best that you choose the crops to plant that can be paired with grey water for not all plants can thrive in grey water. 

There are so many benefits your plants can derive from grey water such as boosting plant growth, increasing crop yield, and creating a cool micro-climate. Using grey water in the garden can help the environment and can minimize your household expenditure.

It is not only grey water that you need to store and utilize. As much as you are preparing for summer drought, You also need to prepare for emergencies by learning how to properly store clean water for survival

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