What Is Graywater?
Graywater is waste water from laundry machines, bathroom sinks, showers, and bathtubs. California law does not allow graywater use from kitchen sinks or dishwashers. In January 2010, the California Building Standards Commission adopted Title 24, Part 5, Chapter 16A into the California Plumbing Code. The new graywater code applies to residential buildings only. The new graywater code facilitates water conservation, relieves stress on private septic systems, makes legal compliance easily achievable, and provides guidelines for avoiding potentially unhealthful conditions.
A typical California household produces more than 10,000 gallons of graywater between May and October. Although some municipalities recycle treated graywater to irrigate agricultural crops, most graywater is sent to a wastewater treatment plant which discharges the treated water to a local waterway or the ocean. Irrigating landscapes with graywater during the summer dry months is a sustainable solution for homes that do not have access to treated recycled water. Graywater irrigation conserves our precious water resources, conserves energy needed to pump and treat water, and saves money on your water bill!
Guidelines for Irrigating with Graywater
The CA graywater code allows residential graywater landscape irrigation from washing machines without a construction permit if the system meets all performance guidelines in the code. Learn how to create a functional graywater irrigation system that conserves water and protects the environment.
Obtaining a Graywater Construction Permit for Simple and Complex Systems
The CA graywater code requires a construction permit for any alteration to your home’s drain/vent plumbing for showers, bathtubs, and bathroom sinks. This section includes contact information for planning departments in the Monterey Bay area and what to expect from the permit process.
Request a Professional Graywater Consultation from a Member of the Central Coast Graywater Alliance
Members of the Central Coast Graywater Alliance can evaluate your home’s potential for graywater reuse and guide you through the permitting process.
Upcoming Graywater Workshops
View a list of current graywater training and workshop opportunities in the Monterey Bay Area.
Graywater Rebates
Soquel Creek Water District customers are eligible for a graywater irrigation system rebate of $75 per fixture.
California American Water Customers (Monterey Peninsula & Carmel) are eligible for a graywater irrigation system rebate of $100 per fixture.
Technical Resources about Graywater Systems
Greywater Action
Oasis Design: Offer outstanding how-to resources for graywater installers.
Graywater Compatible Laundry Detergents (PDF)
Where to Buy Laundry to Landscape Equipment in the Monterey Bay Area (PDF)
Laundry to Landscape Homeowner's Manual (PDF template)
Branched Drain Homeowner's Manual (PDF template)
Constructed Wetland Homeowner's Manual (PDF template)
3-Port Valve Handle Orientation Labels (prints on Avery label sheet)
Graywater Pipe Label (prints on Avery label sheet)
Guidelines for Irrigating with Graywater
■ Designing and installing your graywater system to meet performance standards is good for the environment, and it is the law! Under Title 24, Part 5, Chapter 16A , all graywater irrigation systems must comply with the following guidelines to protect the environment and avoid system failure:
■ Any graywater system that includes a connection to a potable or municipal water supply must have an approved, backflow prevention device. Laundry to landscape graywater irrigation systems that are exempt from permitting must have no connection to the potable water supply or an external pump.
■ The graywater system design must include an accessible, clearly labeled, three-way valve that diverts the graywater back to the building sewer. Graywater should be diverted to the building sewer during the rainy season between November and April.
■ The graywater must not leave the property where it came from or come within 100 feet of any creek, wetland, or waterway.
■ The groundwater table must be lower than 3 feet from the lowest graywater irrigation or disposal point.
■ Each release point of the graywater irrigation system must be covered with at least 2¨of mulch, rock, soil, or a soil shield. Sprinkler irrigation and ponding of graywater are not allowed!
■ Water used to wash diapers or other infectious garments must be diverted to the building sewer.
■ Graywater may not contain hazardous chemicals.
■ Graywater may not be used to irrigate root crops or other edible crops that touch the soil.
■ An operations and maintenance manual for the graywater system must be provided by the installer and must be transferred to the new tenant or owner for the life of the graywater system.
■ Graywater irrigation systems must be located a minimum horizontal distance away from the following landscape features:
Landscape Feature
|
Minimum
Horizontal Distance from Graywater Irrigation System
|
Building structures
|
2 feet (610 mm)
|
Property line adjoining private property
|
1.5 feet (458 mm)
|
Water supply wells
|
100 (30,480 mm)
|
Streams Rivers,,Lakes, Wetlands, and High Tide line of Ocean
|
100 ft (30,480 mm)
|
Sewage pits or cesspools
|
5 (1,524 mm)
|
Sewage disposal field
|
4 (1,219 mm)
|
Septic tank
|
5 (1,524 mm)
|
Onsite domestic
water service line
|
0 (0 mm)
|
Pressurized public water main
|
10 (3,048 mm)
|
For detailed information regarding required setbacks for graywater tanks, graywater irrigation fields, and graywater disposal fields, see Table 16A-1 of Title 24, Part 5, Chapter 16A of the California Plumbing Code.
Obtaining a Graywater Construction Permit for Simple and Complex Systems
Simple and Complex Graywater Systems
Simple systems produce less than 250 gallons a day.
Complex systems produce more than 250 gallons a day.
Whereas laundry systems can utilize the internal pump to send graywater a short distance uphill, most simple and complex graywater systems from bathroom sinks, showers, and tubs rely on gravity to send water through a branched drain irrigation system. The graywater exits the branched drain irrigation piping into a covered mulch basin, and the biology of the soil is the treatment system that digests organic debris, soap, and any potential pathogens. Graywater to drip irrigation is possible, but requires pumping, filtration, and backflow prevention, all of which increase overall system cost and maintenance.
Steps to successfully obtaining a graywater construction permit
Step 1:
Seek professional assistance for designing your graywater system from a member of the Central Coast Graywater Alliance.
Step 2:
MONTEREY COUNTY RESIDENTS:
Unincorporated residents and City properties containing wells and/or septic systems:
Contact Monterey County Health Bureau, Environmental Health Review Service to obtain a permit for your graywater system.
City residents that do not contain a well or septic system:
Contact your local City Building Department to obtain a permit for your graywater system using the template graywater permit (PDF download).
SANTA CRUZ COUNTY RESIDENTS:
All unincorporated County AND City of Santa Cruz residents must begin the graywater permit process by obtaining an environmental health clearance at Santa Cruz County Environmental Health Services (831-454-2022).
Building Permit Application Requirements for Residential Graywater Irrigation Systems (PDF download)
Residents of the Cities of Capitola, Watsonville, and Scotts Valley, must apply directly to their local City Building Department to obtain a graywater construction permit.
Residents of the City of Santa Cruz who have non-permitted clothes washer systems are required to sign, submit, and comply with the Clothes Washer Graywater Systems Installation and Maintenance Agreement Form as published by the City of Santa Cruz Public Works Department (Ordinance No. 2011-04).
Step 3:
If your graywater system requires a pump, tank storage, or a connection to the potable water supply, contact your water supply agency for information on backflow prevention requirements.
What to Expect from a Professional Graywater Consultation & Installation
In order to avoid maintenance and environmental health issues, simple and complex graywater systems should be designed carefully by an experienced professional.
The collection plumbing inside or underneath the house should be performed by a licensed plumber who is familiar with the installation of 3-way valves and conserving the height of fall. If your graywater source is from a bathroom sink or shower/tub, you or your installer are legally required to apply for a construction permit so that the system can be inspected to assure code compliance.
The graywater disposal or irrigation system outside the house should be designed and installed by a licensed landscape professional or environmental engineer. The irrigation system should be designed to ensure that the estimated daily flow from your graywater source(s) match your soil’s infiltration capacity and the irrigation needs of your existing or planned landscape. Irrigation system installation will require digging narrow trenches, mulch basins, and careful pipe installation. Upon the completion and inspection of the graywater installation, the installer should provide you with a map that locates all system components and an operations and maintenance manual. If you are uncomfortable maintaining your graywater system, you should set up a maintenance contract with your installer to ensure optimum system performance. The key to success of your graywater system is a good design and active participation by the user(s) to follow the guidelines in the maintenance manual! All members of the Central Coast Graywater Alliance are plumbing, landscaping, and/or environmental engineering professionals who are committed to creating code-compliant graywater systems.
Central Coast Graywater Alliance Members
Graywater Alliance Member |
Contact Information |
Graywater Collection Plumbing |
Graywater Irrigation Design, Installation & Maintenance |
Engineered Graywater System Design |
(831) 818-3184 |
X |
|||
(831) 471-9100 |
X |
|||
(831) 688-7764 |
X |
|||
(831) 425-3514 |
X |
|||
Monterey Graywater Group |
(831) 402-8229 |
X |
||
Handy Dan Construction and Greenwise Landscaping |
(831)-643-9911 |
X |
X |
|
George Allen Plumbing |
(831) 438-1335 |
X |
||
(831) 476-6800 |
X |
|||
(831) 459-0656 |
X |
|||
Aqua Green Landscape Irrigation |
(831) 251-7362 |
X |
||
(831) 425-2608 |
X |
X |
||
(831) 659-3820 |
X |
|||
(831) 426-9054 |
X |
|||
(831) 430-9116 |
X |
|||
Eco Engineering Inc. |
831-239-3446 |
X |
October 22, 2011, 10am-4pm
2011 Ecology Series: Graywater Clarified
Location: Santa Cruz
DIY installation of laundry to landscape watering system.
To Register: www.ecolandscaping.org
Or for further information call Golden Love: 831-471-9100
In 2010, the Green Gardener Certification Program received funding from the American Recovery and Reinvestment Act grant to develop and pilot a 55-hour graywater system design, installation, and maintenance training course for landscaping and plumbing professionals. Training participants installed and permitted the first residential graywater systems in the Monterey Bay Area. The Green Gardener Graywater Training Program curriculum is available free of charge to any public agency who wishes to implement professional graywater training as part of a green workforce development training program. For more information, please contact Sherry Lee Bryan.
For more information, call Sherry Lee Bryan of Ecology Action, (831) 426-5925 x114.
Sherry Lee Bryan
Ecology Action
Phone: 831.515.1314
Fax: 831.425.1404
Email
.