Greywater Harvesting

Abundant Water for Your Garden:

For people and gardens in the Western United States, greywater is the most available source of water for gardens, and is a key element in a Water Neutral Garden. Currently in the Santa Cruz area, most greywater goes to water treatment plants or septic tanks. Instead, approximately 2.3 million gallons of potential greywater could be used for landscaping. There are three commonly used greywater harvesting 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. When washing diapers, or using bleach or other toxic substances, this valve is turned to the sewer/septic position, therefore preventing harm to plants or the environment. A Laundry to Landscape greywater harvesting system such as 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.

Piping of Laundry to Landscape Greywater Harvesting System behind washing machine

Laundry to Landscape Greywater Harvesting System

Photo of garden with plants being watered by a Laundry to Landscape greywater harvesting system

Laundry to Landscape Greywater 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. Ground covers and vegetables, on the other hand, are watered through tubing with holes covered with a minimum of 2 inches of mulch.

Branched Drain Watering System

2. Branched Drain Watering System (permit required)

This greywater harvesting system operates using gravity. Therefore, your garden must be lower than your shower, bath, or bathroom sinks. A certified plumber is required to redirect the pipes and install a valve (usually under the house) in order to direct water to the landscape or sewer/septic systems. This system consists of piping, usually 1 1/2” or larger. In order to avoid sludge buildup, these systems are designed with 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. Costs include design preparation and hiring a certified plumber for modifications to the waste water piping. Additionally, there are costs for moving the permit through the Environmental Health and Building Departments.

3. Pump/Filter Watering Systems (permit required)

This system provides the most versatility. Like the branched drain system, it can utilize the greywater from the whole house. Unlike the branched drain, however, it is not reliant on gravity. 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 the garden. It is distributed to plants similarly to the Laundry to Landscape system. The cost of this greywater system is usually about $3,500. That includes design, permit processing and fees, and a certified plumber. One Pump/Filter System that Love’s Gardens often installs for our customers is the Aqua2Use. This product contains multiple filters in order to insure the water entering the garden is good for the plants.

An Aqua2Use greywater system filters water from laundry, bath, shower, and lavatories to water landscaping.

Aqua2Use Pump/Filter Greywater Harvesting System

4 Comments

  1. Avatar for Martha Jordan

    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. Avatar for Golden

    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 erinhackett@earthlink.net
    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: http://centralcoastgreywater.org
    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,
    Golden

  3. Avatar for Jasmine Berke

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

  4. Avatar for Golden

    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.
    Thanks,
    Golden

Leave a Reply

Your email address will not be published. Required fields are marked *