Greywater Harvesting

Greywater Harvesting: For people and gardens in the Western United States, greywater is the most available source of water for gardens. Currently in the Santa Cruz area, most of greywater goes to water treatment plants or septic tanks. In this same area, there are approximately 2.3 million gallons of potential greywater that can be used for landscaping and there are three commonly used systems available:

1. Laundry to Landscape Watering Systems (permit exempt): These systems hook-up piping from the washing machine and run it to the garden during the dry season and to the sewer or septic system during wet times. A three-way diverter valve is installed close to the washing machine to manually control where the water goes. It is recommended to turn this valve to the sewer or septic when washing diapers, using bleach, or any other toxic substance that could harm plants or the environment. A system like this can cost from $500 for a simple system to $1,500 for one with multiple zones. Cost also depends on the difficulty of reaching the exterior through walls, cement, or other structures.

Laundry to Landscape Watering System

Laundry to Landscape Watering System

Piping is usually laid on top of the ground for easy maintenance and covered with a 2 – 3 inch layer of wood chips. Mulch basins with outlet shields are created for large shrubs and trees or tubing with holes covered with a minimum of 2 inches of mulch for groundcovers and vegetables.

Branched Drain Watering System

2. Branched Drain Watering System (permit required): This system operates using gravity and requires that your garden be lower than your shower, bath, or bathroom sinks. It requires a certified plumber to redirect the pipes and install a valve (usually under the house) to direct water to the landscape or sewer/septic systems. It consists of piping, usually 1 1/2” or larger and is designed to avoid sludge buildup by having sufficient flow and consistent elevation drop throughout. Approximate cost is $1,500 to $3,000 depending on the difficulty of exiting the source point and concrete impediments. A large part of the cost is preparing a design, hiring a certified plumber for modifications to the waste water piping, and moving the permit through the Environmental Health and Building Departments.

3. Pump/Filter Watering Systems (permit required): This system provides the most versatility. Gardens can be uphill or downhill from the shower, bath, bath sinks, and laundry machine exit pipes. Water drains into a small box and is pumped automatically through 1-inch Polyethelene (PE) piping to plants with a similar distribution system as the Laundry to Landscape Watering System. The cost of this system is usually about $3,500 that includes design, permit processing and fees, and a certified plumber.


  1. I am thinking of diverting the laundry water to an area that has blueberry bushes. I know blueberries require acidic conditions. What do I need to do to counteract the basic condition of laundry water?

  2. Hi Martha,
    Use a laundry ball and plant based stain removers by BioKleen. BacOut is available at Staff of Life and we just spray it on the stain and wait about 5 minutes before putting it in the washing machine with the laundry ball. Erin Hackett, from H2Oat home sells the laundry balls from her local business and can be reached at
    I am happy you are planning to water your garden with your washing machine. There will be Central Coast Greywater Alliance workshops and installations this spring and summer. Check out:
    Also, the Water Festival is coming up next Saturday at Pacific Cultural Center and I will be speaking about greywater and rainwater with other key leaders in the field. It starts at 12:30 pm and goes till 3:30pm.
    Good to hear from you,

  3. I am interested in setting up a gray water system at my house. What kind of experience do you have in this?

  4. Hi Jasmine,
    Thanks for your interest. We have been installing grey water systems for the past 5 years and have certified greywater installers on staff. We installed the first laundry to landscape and permitted pumped greywater systems in Santa Cruz County under the new plumbing code. Please call me at (831) 471-9100 and we can pre-qualify your property for greywater and answer any questions.

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