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California Graywater Standard:
Chapter 16A Nonpotable Water Reuse Systems

Complete Text of California's Greywater Standard adopted August 4th, 2009,
links to history, analysis of significance, science, government web sites, and suggested improvements

For regulators, inspectors, elected officials, building departments, health departments, builders, homeowners, and activists.


On this page:

Full Text of California's Current Greywater Standards

This is the exact text of the current standard, without any changes or comments (later we'll post a fully annotated version with interpretation and suggested improvements here and in our  Builder's Grey Water Guide (book)).

Official PDF of same exact language from HCD web site

 

 

PREFACE

INTRODUCTION

Chapter 16A establishes minimum requirements for the installation of graywater systems in occupancies regulated by the Department of Housing and Community Development (HCD). It is intended to provide guidance to code users while providing flexibility that will encourage the use of graywater. This chapter contains provisions which allow the installation of limited types of graywater systems to be installed without a construction permit. It is not the intent of HCD that the exemption from a construction permit be construed by code users as an exemption from the provisions of this chapter or other lawfully enacted requirements imposed by a city, county, or city and county, nor does it eliminate the need for persons considering the installation of a graywater system from contacting local authorities to ensure they are adequately informed about any local requirements or prohibitions.

DEVELOPMENT

This chapter was developed through input from stakeholders representing a wide variety of interests during several public meetings. These meetings resulted in several drafts, which were distributed to stakeholders for comment. HCD considered these comments and did extensive research on graywater use. Toward the end of the development stage, HCD made a decision to propose these standards on an emergency basis in order to allow the regulations to become effective approximately 18 months sooner than the standard adoption process.

ADOPTION

The emergency graywater regulations, which added Chapter 16A "Nonpotable Water Reuse Systems" into the 2007 California Plumbing Code, were approved by the California Building Standards Commission (CBSC) on July 30, 2009. The emergency regulations were subsequently filed with the Secretary of State on August 4, 2009, effective immediately upon filing.

In compliance with the Administrative Procedure Act, HCD prepared a “Certificate of Compliance” confirming the completion of the rulemaking process, which included a 45-day public comment period, a subsequent 15-day comment period, a Final Statement of Reasons and the Final Express Terms.

The "Certificate of Compliance", along with the Final Express Terms, was unanimously approved by the CBSC and filed with the Secretary of State on January 27, 2010. With the rulemaking action complete, Title 24, Part 5, Chapter 16A, Part I emergency regulations of the 2007 California Plumbing Code were made permanent.

CHAPTER 16A NONPOTABLE WATER REUSE SYSTEMS

Part I

Intent

This part is applicable to occupancies under the authority of the Department of Housing and Community Development as specified in Section 108.2.1.1 and is intended to:

  1. Conserve water by facilitating greater reuse of laundry, shower, lavatory and similar sources of discharge for irrigation and/or indoor use.
  2. Reduce the number of non-compliant graywater systems by making legal compliance easily achievable.
  3. Provide guidance for avoiding potentially unhealthful conditions.
  4. Provide an alternative way to relieve stress on a private sewage disposal system by diverting the graywater.
1601A.0 Graywater Systems – General.
(A)
Except as otherwise provided for in this chapter, the provisions of this code shall be applicable to gray water installation. The provisions of this part shall apply to the construction, alteration, discharge, use, and repair of graywater systems. The graywater system shall not be connected to any potable water system without an air gap or other physical device which prevents backflow and shall not cause the ponding or runoff of graywater. A city, county, or city and county or other local government may, after a public hearing and enactment of an ordinance or resolution, further restrict or prohibit the use of graywater systems. For additional information, see Health and Safety Code Section 18941.7.
(B)
The type of system shall be determined by the location, discharge capacity, soil type, and ground water level. The system shall be designed to handle graywater discharged from the building and may include tank(s) and other appurtenances necessary to ensure proper function of the system.

Note: It is not the intent of this section to require that all graywater must be handled by an irrigation field or disposal field. It is acceptable for excess graywater to be diverted to the building sewer through the overflow required pursuant to Section 1609A.O (E).

(C) No graywater system or part thereof shall be located on any lot other than the lot that is the site of the building or structure that discharges the graywater, nor shall any graywater system or part thereof be located at any point having less than the minimum distances indicated in Table 16A-1.

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 graywater from one lot to an adjoining lot.

(D) No construction permit for any graywater system shall be issued until a plot plan with appropriate data satisfactory to the Enforcing Agency has been submitted and approved. When there is insufficient lot area or inappropriate soil conditions to prevent the ponding or runoff of the graywater, as determined by the Enforcing Agency, no graywater system shall be allowed.

Exception: A construction permit shall not be required for a clothes washer system which does not require cutting of the existing plumbing piping provided it is in compliance with Section 1603A.1.1.

(E)
All graywater systems shall be designed to allow the user to direct the flow to either the irrigation or disposal field or the building sewer. The means of changing the direction of the graywater shall be clearly labeled and readily accessible to the user.
(F)
Water used to wash diapers or similarly soiled or infectious garments or other prohibited contents shall be diverted by the user to the building sewer.
(G)
Graywater 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.
(H)
Human contact with graywater or the soil irrigated by graywater shall be minimized and avoided, except as required to maintain the graywater system. The discharge point of any graywater irrigation or disposal field shall be covered by at least (2) inches (51 mm) of mulch, rock, or soil, or a solid shield to minimize the possibility of human contact.
(I)
Graywater shall not be used to irrigate root crops or edible parts of food crops that touch the soil.
1602A.0 Definitions.

Clothes Washer System. A graywater system utilizing only a single domestic clothes washing machine in a one- or two-family dwelling.

Complex System. Graywater systems that discharge over 250 gallons (947 L) per day.

Disposal Field. An intended destination for graywater including but not limited to a mulch basin or receiving landscape feature, graywater leach field, or other approved method of disposal.

Graywater. Pursuant to Health and Safety Code Section 17922.12, "graywater" means untreated wastewater that has not been contaminated by any toilet discharge, has not been affected by infectious, contaminated, or unhealthy bodily wastes, and does not present a threat from contamination by unhealthful processing, manufacturing, or operating wastes. "Graywater" includes but is not limited to wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines, and laundry tubs, but does not include wastewater from kitchen sinks or dishwashers.

Graywater System. A system designed to collect graywater and transport it out of the structure for distribution in an Irrigation or Disposal Field. A graywater system may include tanks, valves, filters, pumps or other appurtenances along with piping and receiving landscape.

Irrigation Field. An intended destination for graywater in the receiving landscape including but not limited to a drip irrigation system, mulch basin, or other approved method of dispersal for irrigation purposes.

Mulch. Organic waste material including but not limited to leaves, prunings, straw, pulled weeds and wood chips. Mulch shall be permeable enough to allow rapid infiltration of graywater.

Mulch Basin. A type of irrigation or disposal field filled with mulch or other approved permeable material of sufficient depth, length and width to prevent ponding or runoff. A mulch basin may include a basin around a tree, a trough along a row of plants or other shapes necessary for irrigation or disposal.

Receiving Landscape. Includes features such as soil, basins, swales, mulch, and plants.

Simple System. A graywater system serving a one- or two-family dwelling with a discharge of 250 gallons (947 L) per day or less. Simple systems exceed a clothes washer system.

Treated Graywater. Nonpotable water collected and treated on-site suitable for direct beneficial use.

1603A.0 Permit.

A written construction permit shall be obtained from the Enforcing Agency prior to the erection, construction, reconstruction, installation, relocation or alteration of any graywater system that requires a permit.

Exception: A construction permit shall not be required for a clothes washer system which does not

require cutting of the existing plumbing piping provided it is in compliance with Section 1603A.1.1.

1603A.1 System Requirements.

1603A.1.1 Clothes Washer System. A clothes washer system in compliance with all of the following is exempt from the construction permit specified in Section 108.4.1 and may be installed or altered without a construction permit:

    1. If required, notification has been provided to the Enforcing Agency regarding the proposed location and installation of a graywater irrigation or disposal system.
    2. Note: A city, county, or city and county or other local government may, after a public hearing and enactment of an ordinance or resolution, further restrict or prohibit the use of graywater systems. For additional information, see Health and Safety Code Section 18941.7.
  1. 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 graywater shall be clearly labeled and readily accessible to the user.
    1. 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.
    2. Note: The pump in a clothes washer shall not be considered part of the graywater system.
  2. The graywater shall be contained on the site where it is generated.
  3. Graywater shall be directed to and contained within an irrigation or disposal field.
  4. Ponding or runoff is prohibited and shall be considered a nuisance.
  5. Graywater 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.
  6. Graywater systems shall be designed to minimize contact with humans and domestic pets.
  7. Water used to wash diapers or similarly soiled or infectious garments shall not be used and shall be diverted to the building sewer.
  8. Graywater 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.
  9. Exemption from construction permit requirements of this code shall not be deemed to grant authorization for any graywater system to be installed in a manner that violates other provisions of this code or any other laws or ordinances of the Enforcing Agency.
  10. An operation and maintenance manual shall be provided. Directions shall indicate the manual is to remain with the building throughout the life of the system and indicate that upon change of ownership or occupancy, the new owner or tenant shall be notified the structure contains a graywater system.

1603A.1.2 Simple System. Simple systems exceed a clothes washer system and shall comply with the following:

  1. The discharge capacity of a graywater system shall be determined by Section 1606A.0. Simple systems have a discharge capacity of 250 gallons (947 L) per day or less.
  2. Simple systems shall require a construction permit, unless exempted from a construction permit by the Enforcing Agency. The Enforcing Agency shall consult with any public water system (as defined in Health and Safety Code, Section 116275) providing drinking water to the dwelling before allowing and exemption from a construction permit.
  3. The design of simple systems shall be acceptable to the Enforcing Agency and shall meet generally accepted graywater system design criteria.
  4. 1603A.1.3 Complex System. Any graywater system that is not a clothes washer system or simple system shall comply with the following:
  5. The discharge capacity of a graywater system shall be determined by Section 1606A.0. Complex systems have a discharge capacity over 250 gallons (947 L) per day.
  6. Complex systems shall require a construction permit, unless exempted from a construction permit by the Enforcing Agency. The Enforcing Agency shall consult with any public water system (as defined in Health and Safety Code, Section 116275) providing drinking water to the dwelling before allowing and exemption from a construction permit.
  7. A complex system shall be designed by a person who can demonstrate competence to the satisfaction of the Enforcing Agency.

Table 1603A.1.4 – Construction Permit Requirements

Type of System Permit Requirements
Clothes Washer System No construction permit required if conditions in Section 1603A.1.1 are met.
Simple System Permit and plans required unless exempted by Enforcing Agency.
Complex System Permit and plans required unless exempted by Enforcing Agency.
Treated Graywater Permit and plans required unless exempted by Enforcing Agency.
1604A.0 Drawings and Specifications.

Graywater systems for which a construction permit is required may be subject to submittal of plans and details of the proposed graywater system necessary to ensure compliance with the requirements of this chapter. Identification of the groundwater level and soil absorption qualities at the site shall be included in the plans or provided to the Enforcing Agency.

Exception: The Enforcing Agency may waive the requirement for identification of groundwater level

and/or soil absorption qualities based on knowledge of local conditions.

1604A.1 Groundwater Depth. Verification of ground water levels which exceed three (3) vertical feet (915 mm) from the deepest irrigation or disposal point of the proposed graywater system shall not be required.

Note: The absence of groundwater in a test hole three (3) vertical feet (915 mm) below the deepest irrigation or disposal point shall be sufficient to satisfy this section unless seasonal high groundwater levels have been documented to rise to within this area.

1605A.0 Inspection and Testing.

(A) Inspection. A graywater system for which a construction permit is required shall be subject to inspection by the Enforcing Agency and such construction or work shall remain accessible and exposed for inspection purposes until approved.

At the time of final inspection, an operation and maintenance manual shall be provided. Directions shall indicate the manual is to remain with the building throughout the life of the system and upon change of ownership, the new owner shall be notified the structure contains a graywater system

(B) Testing.
(1)
Tanks shall be filled with water to the overflow line prior to and during inspection. Seams and joints shall be left exposed, and the tank shall remain watertight.
(2)
A flow test shall be performed through the system to the point of graywater irrigation or disposal. Lines and components shall be watertight.
1606A.0 Procedure for Estimating Graywater Discharge.

(A) Single Family Dwellings and Multi-Family Dwellings. The graywater discharge for single family and multi-family dwellings shall be calculated by estimates of graywater use based on water use records, calculations of local daily per person interior water use, or the following procedure:

    1. The number of occupants of each dwelling unit shall be calculated as follows:
    2. First Bedroom 2 occupants Each additional bedroom 1 occupant
  1. The estimated graywater flows of each occupant shall be calculated as follows:

Showers, bathtubs 25 GPD (95 LPD)/occupant and wash basins

Laundry 15 GPD (57 LPD)/occupant

3. The total number of occupants shall be multiplied by the applicable estimated graywater discharge as provided above and the type of fixtures connected to the graywater system.

(B) Daily Discharge – Graywater systems using tanks shall be designed to minimize the amount of time graywater is held in the tank and shall be sized to distribute the total amount of estimated graywater on a daily basis.

Exception: Treated graywater systems when approved by the Enforcing Agency.

1607A.0 Required Area of Irrigation or Disposal Fields. Irrigation or disposal fields may have one or more valved zones. Each zone must be of adequate size to receive the graywater anticipated in that zone. No irrigation or disposal field shall extend within three (3) vertical feet (915 mm) of the highest known seasonal groundwater, or to a depth where graywater contaminates the groundwater, ocean water or surface water. The applicant shall supply evidence of groundwater depth to the satisfaction of the Enforcing Agency.

Note: The absence of groundwater in a test hole three (3) vertical feet (915 mm) below the deepest irrigation or disposal point shall be sufficient to satisfy this section unless seasonal high groundwater levels have been documented to rise to within this area.

1608A.0 Determination of Maximum Absorption Capacity.
(A)
Wherever practicable, irrigation or disposal field size shall be computed from Table 16A-2.
(B)
In order to determine the absorption quantities of questionable soils other than those listed in Table 16A-2, the proposed site may be subjected to percolation tests acceptable to the Enforcing Agency.

Exception: Irrigation fields in compliance with Section 1611A.2, which only utilize drip type emitters.

(C) When a percolation test is required, no graywater system shall be permitted if the test shows the absorption capacity of the soil is unable to accommodate the intended discharge of the proposed graywater system. Exception: The Enforcing Agency may waive the requirement for percolation tests based on knowledge of local conditions or accept other testing methods.

1609A.0 Tank Construction.
(A)
When system design includes a tank, specifications for the tank shall be submitted to the Enforcing Agency for approval. Such plans shall show all dimensions and other pertinent data.
(B)
Tanks shall be constructed of solid, durable materials not subject to excessive corrosion or decay and shall be water-tight.
(C)
Each tank shall be vented as required by Chapter 9 of this code, shall be sealed against vermin and mosquitoes, and have an access opening to allow for inspection and cleaning.
(D)
Each tank shall have its rated capacity permanently marked on the unit. In addition, a sign stating "GRAYWATER IRRIGATION SYSTEM, CAUTION — UNSAFE WATER" shall be permanently marked on the holding tank.
(E)
Each tank shall have an overflow drain. The overflow drain shall have a permanent connection to the building drain or building sewer, upstream of septic tanks, if any. The overflow drain shall not be equipped with a shutoff valve.
(F)
The overflow drain shall not be less in size than the inlet pipe. The vent size shall be determined based on the total graywater fixture units as outlined in Table 7-5 of this code. Unions or equally effective fittings shall be provided for all piping connected to the holding tank.
(G)
Each tank shall be structurally designed to withstand all anticipated earth or other loads. Tank covers shall be capable of supporting an earth load of not less than three hundred (300) pounds per square foot (1,464.7 kg/m2) when the tank is used for underground installation.
(H)
The overflow system must be designed so that the tank overflow will gravity drain to the existing sewer line or septic tank. The tank shall be protected against sewer line backflow by a backwater valve.
(I)
An overflow drain and backwater valve is not required on a clothes washer system.
1610A.0 Graywater Systems.

Graywater systems shall comply with Sections 1610A.1 through 1610A.3.

1610A.1 Pipe Materials. Graywater pipe, valves and fittings shall conform to the requirements of Sections 604.0, 605.0 and 606.0.

1610A.2 Identification. Graywater distribution piping upstream of any connection to an irrigation or disposal field or a distribution valve shall be identified with the words "CAUTION: NONPOTABLE WATER, DO NOT DRINK." Marking shall be at intervals not to exceed five (5) feet (1,524 mm).

1610A.3 Valves. All valves shall be accessible. A backwater valve installed pursuant to this code shall be provided on all tank drain connections to the sanitary drain or sewer piping.

1611A.0 Irrigation, Disposal Field and Mulch Basin Construction.

Irrigation fields, disposal fields and mulch basins used in graywater systems shall comply with this section. Graywater systems may contain either a irrigation field or a disposal field or a combination of both. This section is not intended to prevent the use of other methods of graywater irrigation or disposal approved by the Enforcing Agency.

1611A.1 Mulch Basin A mulch basin may be used as an irrigation or disposal field. Mulch basins shall be sized in accordance with Table 16A-2 and of sufficient depth, length and width to prevent ponding or runoff during the graywater surge of a clothes washer, bathtub or shower. Mulch must be replenished as required due to decomposition of organic matter. Mulch basins will require periodic maintenance, reshaping or removal of dirt to maintain surge capacity and to accommodate plant growth and prevent ponding or runoff,

1611A.2 Irrigation Field. The provisions of this section are not intended to prevent the use of any appropriate material, appliance, installation, device, design or method of construction. If an alternate design is not available, the following provisions may be used as guidance in the design of a graywater irrigation field:

(1)Filters used in graywater irrigation systems shall be as specified by the manufacturer’s installation instructions for the design flow rate and intended use. The filter backwash and flush discharge shall be contained and disposed of into the building sewer system, septic tank or, with approval of the Enforcing Agency, a separate mini-leachfield sized to accept all the backwash and flush discharge water. Filter backwash water and flush water shall not be used for any purpose. Sanitary procedures shall be followed when handling filter backwash and flush discharge or graywater.

(2)
Emitters shall be designed to resist root intrusion and shall be of a design recommended by the manufacturer for the intended graywater flow and use. For emitter ratings, refer to Irrigation Equipment Performance Report, Drip Emitters and Micro-Sprinklers, Center for Irrigation Technology, California State University, 5730 N. Chestnut Avenue, Fresno, California 93740-0018.
(3)
Each irrigation zone shall be designed to include no less than the number of emitters specified in Table 16A-3, or through a procedure designated by the Enforcing Agency. Minimum spacing between emitters is in any direction shall be sufficient to prevent surfacing or runoff.
(4)
The system design shall provide user controls, such as valves, switches, timers and other controllers, as appropriate, to rotate the distribution of graywater between irrigation zones.
(5)
All drip irrigation supply lines shall be polyethylene tubing or PVC Class 200 pipe or better and Schedule 40 fittings. All joints shall be properly solvent-cemented, inspected and pressure tested at 40 psi (276 kPa), and shown to be drip tight for five minutes, before burial. All supply piping shall be covered to a minimum depth of two (2) inches (51 mm) of mulch or soil. Drip feeder lines can be poly or flexible PVC tubing and shall be covered to a minimum depth of two (2) inches (51 mm) of mulch or soil.
(6)
Where pressure at the discharge side of the pump exceeds 20 psi (138 kPa), a pressure-reducing valve able to maintain downstream pressure no greater than 20 psi (138 kPa) shall be installed downstream from the pump and before any emission device.
(7)
Each irrigation zone shall include a flush valve/antisiphon valve to prevent back siphonage of water and soil.

1611A.3 Disposal Field. The provisions of this section are not intended to prevent the use of any appropriate material, appliance, installation, device, design or method of construction. If an alternate design is not available the following provisions may be used as guidance in the design of a graywater disposal field:

(A)
Disposal systems shall be not less than three (3) inches (80 mm) in cross sectional dimension and shall be constructed of perforated high-density polyethylene pipe, perforated ABS pipe, perforated PVC pipe, leaching chambers or other approved materials, provided that sufficient openings are available for distribution of the graywater into the trench area. Material, construction, and perforation shall be in compliance with the appropriate absorption fields drainage standards and shall be approved by the Enforcing Agency.
(B)
Filter material, clean stone, gravel, slag, or similar filter material acceptable to the Enforcing Agency, varying in size from three-quarter (3/4) inch (19.1 mm) to two and one-half (2-1/2) inches (64 mm) shall be placed in the trench to the depth and grade required by this section. The perforated section shall be laid on the filter material in an approved manner. The perforated section shall then be covered with filter material to the minimum depth required by this section. The filter material shall then be covered with untreated building paper, straw, or similar porous material to prevent closure of voids with earth backfill. No earth backfill shall be placed over the filter material cover until after inspection and acceptance.

Exception. Manufactured leaching chambers shall be installed in compliance with the manufacturer’s installation instructions.

(C) Disposal fields shall be constructed as follows:

(See chart below)

Minimum Maximum
Number of drain lines per valved zone1 1
Length of each perforated line1 100 ft. (30,840 mm)
Bottom width of trench1 12 in. (305 mm) 24 in. (610 mm)
Spacing of lines, center to center1 4 ft. (1219 mm)
Depth of earth cover of lines 2 in. (51 mm)
Depth of filter material cover of lines 2 in. (51 mm)
Depth of filter material beneath lines1 3 in. (76 mm)
Grade of perforated lines level 3 in./100 ft. (2 mm/m)

1 Manufactured leaching chambers shall be installed in compliance with the manufacturer’s installation instructions.

(D) When necessary on sloping ground to prevent excessive line slopes, disposal lines shall be stepped or installed on the contour lines of the slope. The lines between each horizontal leaching section shall be made with approved water-tight joints and installed on natural or unfilled ground.

1612A.0 Special Provisions
(A)
Other collection and distribution systems shall be permitted by the local Enforcing Agency, as allowed by Section 108.7 of this code.
(B)
Nothing contained in this chapter shall be construed to prevent a city, county, or city and county or other local government from, after a public hearing and enactment of an ordinance or resolution, further restricting or prohibiting the use of graywater systems. For additional information, see Health and Safety Code Section 18941.7.
(C)
Graywater stub-out plumbing may be allowed for future connection prior to the installation of irrigation lines and landscaping. Stub-out shall be permanently marked “GRAYWATER STUB-OUT, CAUTION --UNSAFE WATER”.
Table 16A -1 Location of Graywater System
Minimum Horizontal Distance Required From: Tank Irrigation Field Disposal Field
Feet/mm Feet/mm Feet/mm
Building structures1 5 (1,524 mm)2 2 (610 mm) 5 (1,524 mm)
Property line adjoining private property 5 (1,524 mm) 1.5 feet (458 mm) 5 (1,524 mm)
Water supply wells3 50 (15,240 mm) 100 (30,480 mm) 100 (30,480 mm)
Streams and lakes3 50 (15,240 mm) 100 (30,480 mm)4,5 100 (30,480 mm)4
Sewage pits or cesspools 5 (1,524 mm) 5 (1,524 mm) 5 (1,524 mm)
Sewage disposal field 5 (1,524 mm) 4 (1,219 mm)6 4 (1,219 mm)6
Septic tank 0 (0) 5 (1,524 mm) 5 (1,524 mm)
Onsite domestic water service line 5 (1,524 mm) 0 (0 mm) 0 (0 mm)
Pressurized public water main 10 (3,048 mm) 10 (3,048 mm)7 10 (3,048 mm)7

1 Building structures does not include porches and steps, whether covered or uncovered, breezeways, roofed porte cocheres, roofed patios, carports, covered walks, covered driveways, and similar structures or appurtenances. 2 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. 3Where special hazards are involved, the distance required shall be increased as directed by the Enforcing Agency. 4These minimum clear horizontal distances shall also apply between the irrigation or disposal field and the ocean mean higher hightide line.5The minimum horizontal distance may be reduced to 50 feet (15,240 mm) for irrigation fields utilizing graywater which has been filtered prior to entering the distribution piping.

6 Plus two (2) feet (610 mm) for each additional foot of depth in excess of one (1) foot (305 mm) below the bottom of the drain line. 7For parallel construction or crossings, approval by the Enforcing Agency shall be required.

Table 16A-2 Design Criteria of Six Typical Soils

Type of Soil Square Feet Gallons Square Meters Liters
Minimum square feet of irrigation/leaching area per 100 gallons of estimated graywater discharge per day Maximum absorption capacity in gallons per square foot of irrigation/leaching area for a 24-hour period Minimum square meters of irrigation/leaching area per liter of estimated graywater discharge per day Maximum absorption capacity in liters per square meter of irrigation/leaching area for a 24-hour period
Coarse sand or gravel 20 5.0 0.005 203.7
Fine sand 25 4.0 0.006 162.9
Sandy loam 40 2.5 0.010 101.8
Sandy clay 60 1.7 0.015 69.2
Clay with considerable sand or gravel 90 1.1 0.022 44.8
Clay with small amounts of sand or gravel 120 0.8 0.030 32.6

9 of 10 Certificate of Compliance with Final Express Terms Filed with the Secretary of State on January 27, 2010 (2007 CPC, Title 24, Part 5, Chapter 16A, Part I – Nonpotable Water Reuse Systems)

Table 16A-3 Subsurface Drip Design Criteria of Six Typical Soils

Type of Soil Maximum emitter discharge (gal/day) Minimum number of emitters per gpd of graywater production
1.Sand 1.8 0.6
2.Sandy loam 1.4 0.7
3.Loam 1.2 0.9
4.Clay loam 0.9 1.1
5.Silty clay 0.6 1.6
6.Clay 0.5 2.0

Use the daily graywater flow calculated in Section 1606A.0 to determine the number

of emitters per line.

1612A.1 Indoor Use of Treated Graywater.

Graywater shall not be allowed for indoor use, such as flushing toilets and urinals, unless treated by an onsite water treatment system approved by the Enforcing Agency. For the purposes of this section, graywater treated by an on-site water treatment system shall be considered “Treated Graywater”. Treated graywater and treated graywater systems shall comply with the provisions of this code except as otherwise provided in this chapter and all of the following:

(1)
The treated graywater shall have a separate tank sized to minimize the length of time it is retained.
(2)
A maintenance and operation manual for the treatment system shall be kept at the location of the system.
(3)
Treated graywater intended for use indoors shall meet the California Department of Public Health statewide uniform criteria for disinfected tertiary recycled water as provided in California Code of Regulations, Title 22 Section 60301.230.
(4)
The treated graywater system shall be installed, inspected and tested as specified for reclaimed water systems in Sections 1618.0 and 1620.0.

NOTE:

Authority Cited: Health and Safety Code Sections 17040, 17921, 17922 and 19990.

Reference: Health and Safety Code Sections 17922.12 and 18941.7.

Standards for Permit-Free Clothes Washer/ Single Fixture System

Excerpted from the full text, below. Systems that meet these standards do not require a permit or inspection.

 

1603A.1.1 Clothes Washer System. A clothes washer system in compliance with all of the following is exempt from the construction permit specified in Section 108.4.1 and may be installed or altered without a construction permit:

    1. If required, notification has been provided to the Enforcing Agency regarding the proposed location and installation of a graywater irrigation or disposal system.
    2. Note: A city, county, or city and county or other local government may, after a public hearing and enactment of an ordinance or resolution, further restrict or prohibit the use of graywater systems. For additional information, see Health and Safety Code Section 18941.7.
  1. 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 graywater shall be clearly labeled and readily accessible to the user.
    1. 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.
    2. Note: The pump in a clothes washer shall not be considered part of the graywater system.
  2. The graywater shall be contained on the site where it is generated.
  3. Graywater shall be directed to and contained within an irrigation or disposal field.
  4. Ponding or runoff is prohibited and shall be considered a nuisance.
  5. Graywater 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.
  6. Graywater systems shall be designed to minimize contact with humans and domestic pets.
  7. Water used to wash diapers or similarly soiled or infectious garments shall not be used and shall be diverted to the building sewer.
  8. Graywater 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.
  9. Exemption from construction permit requirements of this code shall not be deemed to grant authorization for any graywater system to be installed in a manner that violates other provisions of this code or any other laws or ordinances of the Enforcing Agency.
  10. An operation and maintenance manual shall be provided. Directions shall indicate the manual is to remain with the building throughout the life of the system and indicate that upon change of ownership or occupancy, the new owner or tenant shall be notified the structure contains a graywater system.

 

How to Resources:

 

 

What Local Jurisdictions Should Take into Account Before Amending This Standard

The new California standard is the culmination of an extensive stakeholder review process with extensive input from building officials, health officials, inspectors, industry and environmental representatives.

Some local jurisdictions are considering altering the new California greywater code in ways that are likely to have the opposite of the effect desired.

Before altering the standard, it would be wise to:

  1. Gain a complete understanding of the history and realities of California greywater use, not just the one in 10,000 systems that were built with permits, but the other 1.7 million existing systems
  2. Get a complete view of the risks and benefits of greywater reuse.

 

A point of much discussion is the question of whether the most basic class of systems should be

  1. allowed to be built without permits if they meet standards, as in AZ, NM, and TX
  2. registered, or—
  3. permitted and inspected

In an effort to maintain control, California attempted "3" the past 20 years. However, Californians do not want to pay $100 for a permit for a system that has less than $100 in parts.

The unintended consequence was to drive greywater reuse completely outside of reach of the potential positive influence of government agencies, building inspectors, licensed professionals, or experienced installers. Virtually all the state's 1.7 million greywater systems are homeowner-built systems that feature uncontained surface application of greywater.

This giant experiment —

  1. inadvertently proved that it is very difficult to get sick from greywater; there hasn't been a single documented case of greywater-transmitted illness in the US.
  2. proved that pushing too hard for control causes a loss of control.

There is very little traction for greywater regulation. The best approach is with a light hand, focusing on:

The current standards take this approach, by requiring no permit for the most basic systems, and providing for increasing oversight of increasingly complex or worrisome systems.

For more details and supporting facts and figures on the above, please read these two documents:

Full text of Art Ludwig's testimony to the BSC

Handout to BSC (PDF) includes reasons to have standards but not require a permit for simple systems

 

Notification/ Registration of Greywater Systems

Notification/ registration of greywater systems (or a certificate of negative declaration) have been proposed as a possible compromise between permitting and not permitting. The current standard allows this option:

 

If required, notification has been provided to the Enforcing Agency regarding the proposed location and installation of a graywater irrigation or disposal system.

 

At first I was excited about this, but then I realized that this would probably be less satisfactory than either of the other scenarios.

I assume that these are the goals of registration:

  1. Better systems
  2. Better understanding of what is happening in the district
  3. Greater control
  4. Increasing knowledge base concerning what types of systems, uses, waste streams, application rates, treatment devices are most effective for managing graywater reuse.
  5. Encouraging communication between graywater system users and the public sector
  6. Establishment of a user database so new developments in graywater reuse can be made available to those who have participated in the notification process

Registration is likely to have the opposite of the desired effect for every one of these goals. Here's why:

  1. The chilling effect of a registration requirement on professional installations is probably worse than requiring a permit. Homeowners would perceive it as an open invitation to inspect the site at any time in the future. The likely result is that installations will be done by unskilled homeowners without benefit of professional assistance in order to avoid registration. In many areas, the reduction in numbers of professional installations may cross the threshold of viability of greywater installations as a business (it is a low margin business to begin with), with the result that even those that would be happy to have their systems done professionally and registered won’t have the option of professional help. The result: worse systems than would be achieved under the "standards but no permits" scenario (which eliminates all barriers to installation by licensed professionals).
  2. With the vast majority of the greywater systems driven underground, the sample will be of little statistical or other value. Ditto for the rest of the points...with 9999 out of 10,000 installations unregistered, little benefit will be gained.

If your jurisdiction is interested in registration, here's an approach that, while it aims a bit lower, I think will actually hit the targets: (I've written it here in the form of suggested language for the state standard, it certainly would be allowed under the current language quoted above)

 

At the Enforcing Agency’s discretion, the Enforcing Agency may inspect clothes washer and/or single fixture systems concurrent with an inspection on the property for another purpose, an enforcement action for another purpose, or an otherwise required inspection on sale of a property.

 

Here's the details:

  1. When permitted new construction or remodeling includes a greywater system, the greywater system must be registered to add to the county's experimental best practices database. The trigger could be set anywhere desired, from any permit at all—re-roof your house, greywater system gets registered—to highly selective—new construction, for sure, and maybe major replumbing.
  2. Greywater systems could be voluntarily registered
  3. When there is a complaint, the greywater system would be registered, and this form of registration unlike the others, would constitute justification for follow up visits.

So ...I think this gives the best of both worlds:

  1. whenever an inspector is already at a site, the county would get another entry in their database. Peoples bubble of privacy is already penetrated at this point, so it wouldn't seem so calamitous. The sample could include all new construction and remodeling, adding sizable, non-self selected chunk of data to the system that had just one independent variable (a permit for something else) rather than the highly biased sample you'd get from people who for some reason came forward for with mandatory registration.
  2. Voluntary registration would presumably get a few exemplary systems out of the woodwork and into the database, perhaps systems installed by professionals looking to add credibility to their work.
  3. Complaint based-registration would get samples from the opposite end--lousy, problematic systems—into the database, and would provide an incentive to people to keep their greywater noses clean, and a mechanism for tracking, monitoring, and actively abating that small percentage of systems that doubtless contribute disproportionately to lowering the average performance.

If your jurisdiction is interested in going this route, please E mail us; I'd be interested in helping develop optimal language.

 

Art Ludwig

 

Links to California Greywater Resources

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