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. Costs for Laundry to Landscape greywater harvesting systems vary depending on such factors as the number of zones to be watered, the distance from the washing machine to the plants, and the difficulty of reaching the exterior through walls, cement, or other structures.
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.
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. Costs vary 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. Contact us for a free evaluation!
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 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.
