Gray water systems shall be verified in accordance with the California Green Building Standards Code (CALGreen), Chapter 5, Division 5.3.
The provisions of this section shall apply to the construction, alteration, and repair of gray water systems. A city, county, or city and county or other local government may adopt, after a public hearing and enactment of an ordinance or resolution, building standards that are more restrictive than the gray water building standards adopted in this code. For additional information, see Health and Safety Code Section 1894 1.7.
- All gray water systems shall be designed with a diverter valve to allow the user to direct the flow to the building sewer and either the irrigation field or disposal field, whichever is used. The means of changing the direction flow of the gray water shall be clearly labeled and readily accessible to the user.
- Water used to wash diapers or similarly soiled or infectious garment s or other prohibited contents shall be diverted by the user to the building sewer.
- Gray water shall not be used in spray irrigation, allowed to pond or runoff and shall not be discharged directly into or reach any storm sewer system or any surface body of water.
- Human contact with gray water or the soil irrigated by gray water shall be minimized and avoided, except as required to maintain the gray water system. The discharge point of any gray water subsoil irrigation or subsurface irrigation field shall be covered by at least two (2) inches (51 mm) of mulch, rock, or soil, or a solid shield to minimize the possibility of human contact.
- Gray water may be released above the ground surface provided at least two (2) inches (5 I mm) of mulch, rock, or soil, or a solid shield covers the release point. Other methods which provide equivalent separation are also acceptable.
- Gray water shall not contain hazardous chemicals derived from activities such as cleaning car parts, washing greasy or oily rags, or disposing of waste solutions.
- [HCD 1] The prohibition in Subsection (F) includes, but is not limited to, home photo labs or other similar hobbyist or home occupational activities.
- [BSC] Photo labs or similar activities.
- Exemption from construction permit requirements of this code shall not be deemed to grant authorization for any gray water system to be installed in a manner that violates other provisions of this code or any other laws or ordinances of the Enforcing Agency.
- An operation and maintenance manual shall be provided to the owner. Directions shall indicate that the manual is to remain with the building throughout the life of the system and upon change of ownership or occupancy.
- A gray water system shall not be connected to any potable water system without an air gap, reduced-pressure principle backflow preventer, or other physical device which prevents backflow and shall not cause ponding or runoff of gray water.
A clothes washer system in compliance with all of the following is exempt from the construction permit specified in Section 1.8.4.1 and may be installed or altered without a construction permit:
- If required, notification has been provided to the enforcing agency regarding the proposed location and installation of a gray water irrigation or disposal system.
- The design shall allow the user to direct the flow to the irrigation or disposal field or the building sewer. The direction control of the gray water shall be clearly labeled and readily accessible to the user.
- The installation, change, alteration, or repair of the system does not include a potable water connection or a pump and does not affect other building, plumbing, electrical, or mechanical components including structural features, egress, fire-life safety, sanitation, potable water supply piping, or accessibility.
Note: The pump in a clothes washer shall not be considered part of the gray water system. - The gray water shall be contained on the site where it is generated.
- Gray water shall be directed to and contained within an irrigation or disposal field.
- Ponding or runoff is prohibited and shall be considered a nuisance.
- Gray water may be released above the ground surface provided at least two (2) inches (51 mm) of mulch, rock, or soil, or a solid shield covers the release point. Other methods which provide equivalent separation are also acceptable.
- Gray water systems shall be designed to minimize contact with humans and domestic pets.
- Water used to wash diapers or similarly soiled or infectious garments shall not be used and shall be diverted to the building sewer.
- Gray water shall not contain hazardous chemicals derived from activities such as cleaning car parts, washing greasy or oily rags, or disposing of waste solutions from home photo labs or similar hobbyist or home occupational activities.
- Exemption from construction permit requirements of this code shall not be deemed to grant authorization for any gray water system to be installed in a manner that violates other provisions of this code or any other laws or ordinances of the enforcing agency.
- An operation and maintenance manual shall be provided to the owner. Directions shall indicate that the manual is to remain with the building throughout the life of the system and upon change of ownership or occupancy.
- Gray water discharge from a clothes washer system through a standpipe shall be properly trapped in accordance with Section 1005.0.
Simple systems exceed a clothes washer system and shall comply with the following:
- The discharge capacity of a gray water system shall be determined by Section 1503.8. Simple systems have a discharge capacity of 250 gallons (947 L) per day or less.
- Simple systems shall require a construction permit, unless exempted from a construction permit by the Enforcing Agency. The Enforcing Agency shall consult with the water purveyor for any public water system (as defined in Health and Safety Code Section 1162 7 5) providing drinking water to the dwelling or non-residential structure before allowing an exemption from a construction permit.
- The design of simple systems shall meet generally accepted gray water system design criteria.
Any gray water system that is not a clothes washer system or simple system shall comply with the following:
- The discharge capacity of a gray water system shall be determined by Section 1503.8. Complex systems have a discharge capacity over 250 gallons (947 L) per day.
- Complex systems shall require a construction permit, unless exempted from a construction permit by the Enforcing Agency. The Enforcing Agency shall consult with the water purveyor for any public water system (as defined in Health and Safety Code, Section 1162 7 5) providing drinking water to the dwelling or non-residential structure before allowing an exemption from a construction permit.
Gray water shall be permitted to be diverted away from a sewer or private sewage disposal system, and discharge to a subsurface irrigation or subsoil irrigation system, or disposal field. The gray water shall be permitted to discharge to a mulch basin for residential occupancies. Gray water shall not be used to irrigate root crops or food crops intended for human consumption that comes in contact with soil.
Gray water systems shall be designed to have the capacity to accommodate peak flow rates and distribute the total amount of estimated gray water on a daily basis to a subsurface irrigation field, subsoil irrigation field, disposal field, or mulch basin without surfacing, ponding, or runoff. A surge tank is required for systems that are unable to accommodate peak flow rates and distribute the total amount of gray water by gravity drainage. The water discharge for gray water systems shall be determined in accordance with Section 1503.8.1 or Section 1503.8.2.
Exception: It is not the intent of this section to require that all gray water must be handled by an irrigation field or disposal field. It is acceptable for excess gray water to be diverted to the building sewer through a diverter valve or overflow drain as permitted in this chapter.
The gray water system shall connect to the sanitary drainage system downstream of fixture traps and vent connections through an approved diverter valve. The diverter valve shall be installed in a readily accessible location and clearly indicate the direction of flow.
Exception: [HCD 1] A clothes washer system in compliance with Section 1503.1.1.
Gray water drains subject to backflow shall be provided with a backwater valve at the point of connection to the building sewer system, so located as to be accessible for inspection and maintenance.
Gray water systems shall have no direct connection to a potable water supply, on-site treated nonpotable water supply, or reclaimed (recycled) water supply systems.
Exceptions:
- Potable water, on-site treated nonpotable water, reclaimed (recycled) water, or rainwater is permitted to be used as makeup water for a non-pressurized storage tank provided the connection is protected by an air gap in accordance with this code.
- A potable water supply may be connected temporarily for initial testing of the untreated graywater system as required in Section 1502.3.2.
No gray water system or part thereof shall be located on a lot other than the lot that is the site of the building or structure that discharges the gray water, nor shall a gray water system or part thereof be located at a point having less than the minimum distances indicated in Table 1503.4.
Exception: When there exists a lawfully recorded perpetual and exclusive covenant to an easement appurtenant and right-of-way between adjoining land-owners of two or more contiguous lots to discharge gray water from one lot to an adjoining lot.
| MINIMUM HORIZONTAL DISTANCE IN CLEAR REQUIRED FROM | SURGE TANK (feet) | SUBSURFACE AND SUBSOIL IRRIGATION FIELD AND MULCH BASIN (feet) | DISPOSAL FIELD |
|---|---|---|---|
| Building structures1 | 52, 3, 9 | 23, 8 | 5 |
| Property line adjoining private property | 5 | 58 | 5 |
| Water supply wells4 | 50 | 100 | 100 |
| Streams and lakes4 | 50 | 1005, 10 | 1005 |
| Sewage pits or cesspools | 5 | 5 | 5 |
| Sewage disposal field10 | 5 | 46 | 46 |
| Septic tank | 0 | 5 | 5 |
| On-site domestic water service line | 5 | 0 | 0 |
| Pressurized public water main7 | 10 | 107 | 107 |
For SI units: 1 foot= 304.8 mm
Notes:
- 1 Building structures do not include porches and steps, whether covered or uncovered , breezeways , roofed carports, roofed porte cocheres, roofed patios, carports, covered walks, covered driveways, and similar structures or appurtenances.
- 2 The distance shall be permitted to be reduced to 0 feet for aboveground tanks where first approved by the Authority Having Jurisdiction.
- 3 Underground tanks shall not be located within a 45 degree angle from the bottom of the foundation, or they shall be designed to address the surcharge imposed by the structure. The distance may be reduced to six (6) inches (153 mm) for aboveground tanks when first approved by the Enforcing Agency.
- 4 Where special hazards are involved, the distance required shall be increased as directed by the Authority Having Jurisdiction.
- 5 These minimum clear horizontal distances shall apply between the irrigation or disposal field and the ocean mean higher high tide line.
- 6 Add 2 feet (610 mm) for each additional foot of depth more than 1 foot (305 mm) below the bottom of the drain line.
- 7 For parallel construction or crossings, approval by the Authority Having Jurisdiction shall be required.
- 8 The distance shall be permitted to be reduced to 11/2 feet (457 mm) for drip and mulch basin irrigation systems.
- 9 The distance shall be permitted to be reduced to O feet for surge tanks of 75 gallons (284 L) or less.
- 10 The minimum horizontal distance may be reduced to 50 feet (15 240 mm) for irrigation or disposal fields utilizing gray water which has been filtered prior to entering the distribution piping.
No permit for a gray water system shall be issued until a plot plan with data satisfactory to the Authority Having Jurisdiction has been submitted and approved.
Exception: [HCD 1] A construction permit shall not be required for a clothes washer system in compliance with Section 1503.1.1.
Where there is insufficient lot area or inappropriate soil conditions for adequate absorption, no gray water system shall be permitted.