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Harvesting Greywater for Garden Usage

by Tiffany in Gardening

Harvesting Greywater for Garden UsageOne of the most cost-effective and eco-friendly things a gardener can do is recycle water for use in the garden. Harvesting greywater to water vegetable plants and trees helps them thrive during times of drought, reduces your carbon footprint on the earth and will also help to lower your household’s water expenses.

What is Greywater?

Greywater is water that has already been used in other household applications and gone down the drain. Water from sinks, showers, bath tubs and washing machines is called greywater. The used water will have traces of dirt, soap, hair, grease and household cleaning products in it which makes it have a grayish color, that’s how the gently used water got its name. These trace elements in the greywater can actually be good for plants and provide them with nutrients that help them grow. It all depends on what else gets washed down the drain.

Water from toilets is not suitable for recycling in the garden, nor is laundry water which has been used to wash cloth diapers. Toxics like paints, hair dye, or harsh cleaners, should never enter the greywater system, and should instead be routed through the municipal sewer.

How It’s Harvested

It will require a little elbow grease and perhaps some ingenuity to set up a catchment system for the greywater so it can be harvested and re-used.

PVC pipe can be attached to the drain systems of sinks, showers, tubs and washing machines so the used water can drain off to a separate location instead of going into the septic system. PVC pipes can be installed underground and take the water directly to the garden to provide moisture to growing plants from below the soil level.

PVC pipes can be connected to in-house drains and fabricated to carry the greywater to a central outdoor holding location so that the used water can be re-used at the gardener’s discretion.

A very simple and easy approach some homeowners use to catch greywater is to install drain pipes under the sinks, tubs and washing machines and run the open end of the pipes through the exterior walls to the outside. Barrels or tubs are placed under the open-ended pipes to catch the greywater and the gardener can use it as needed.

You will likely need to make some changes in what products you use and send down the drain but you won’t always be perfect so your system should have a three-way valve, which will allow wastewater to be routed back through the sewer as needed. A good filter designed for recycling greywater for garden use is also a good idea!

Household Changes

If water is to be re-used on plants, a few changes may be needed in the household to make the water safe for plant life. Using safer soaps for cleaning and bathing will be good for both you and your garden. Look for products that are biodegradable or biocompatible. Harsh cleaning chemicals, like chlorine bleach, will need to be avoided too. You will need to become a label reader if you are not already but all that water for your garden is worth it! And honestly if the product is not good for the earth can it really be that good for your body? Think about it.

Product Ingredients to Avoid in Greywater:

  • boron/borax
  • any ingredient with the word “sodium” in it
  • chlorine bleach
  • sodium perborate
  • sodium hypochlorite
  • petroleum distillate
  • alkylbenzene
  • water softeners
  • anti-bacterial soaps & cleaners
  • optical brighteners
  • enzymes
  • titanium oxide
  • chromium oxide
  • artificial colors
  • synthetic fragrance

Good laundry detergents for greywater systems:

Homemade detergents – the ones based on soap and washing soda – are not an option because of their salt content.

Good soaps and shampoos for greywater systems:

Read your labels!! Most bar soaps have sodium ingredients so liquid is your best bet.

Once you get your greywater system set up and you buy the right household products, you can feel confident that you can sustain a garden even through droughts by simply reusing the water from your household. Good luck!

  • Maggie

    What a great idea! We’ve thought about catching rainwater but never the graywater. We normally use a lot of natural cleaning products so that wouldn’t be a problem. I’ll show this to my husband to see what he thinks and if it would be doable.

  • Erin Elizabeth Beaupre

    This is something I had not heard of before! Thanks for opening my eyes to the possibility.

  • Censie ‘Mumby’ Sawyer

    How interesting I have never heard this before. I would love to really start focusing on our garden again. Ready for spring!!

  • maria @ close to home

    I have never heard of greywater before. This is something we might do this spring.

  • Simply At Home Mom

    This sounds like a wonderful way to use leftover water and lower our water bill too! I am willing to try anything to reduce our carbon footprint.

  • I do this quite often, using gray water is smart and economical! I often wash dishes in a small dish tub to save the water.

  • Good info. Love Dr. Bronners! We use it for everything!

  • What a great way to reuse water. I’ll have to keep it in mind if we ever set up a large enough garden.

  • I have been thinking about this since we live in California! I feel guilty watching the cold water go down the shower drain every time!!

  • Lori Popkewitz Alper

    Very interesting Tiffany! Something that I’ve never tried, but it makes perfect sense. Why not reuse that water- especially given that so many areas are experiencing a drought.

  • I am glad you spelled out products ingredients to avoid so you can safely use your greywater.