Section 110. Design criteria

A. Reclamation system.

1. The design of systems for the reclamation of municipal wastewater or source water derived from a municipal wastewater treatment works shall adhere to the standards of design and construction specified in the Sewage Collection and Treatment Regulations (9VAC25-790) and other applicable engineering standards and regulations. Design standards for reclamation systems of industrial wastewater or source water derived from an industrial wastewater treatment works shall be determined and evaluated on a case-by-case basis.

2. Ultraviolet (UV) disinfection for reclamation systems:

a. For Level 1 reclaimed water:

(1) Designs for UV disinfection shall be validated in accordance with NWRI Ultraviolet Disinfection Guidelines for Drinking Water and Water Reuse, Second Edition (2003) (guidelines) to meet a UV design dosage greater than or equal to 100,000 uWsec/cm² (MS-2 dose) under peak flow and a minimum UV transmittance of 55% at 254 nm. A lower UV disinfection dosage may be authorized by the board if demonstrated to meet at least one of the bacteria standards for Level 1 specified in 9VAC25-740-70 A, and where microbial testing is used to validate the efficacy of the UV disinfection dose in accordance with the guidelines. For the lower disinfection dose, the board may develop reclaimed water turbidity standards and minimum UV transmittance requirements that are unique to the UV disinfection process of the reclamation system.

(2) The UV disinfection system shall be designed to supply the minimum dose specified in subdivision 2 a (1) of this subsection at all times. The system may be automated to immediately adjust the UV disinfection dosage in response to changes in the UV system influent reclaimed water flow and quality.

b. UV disinfection for Level 2 reclaimed water shall be designed, constructed, and operated in accordance with the Sewage Collection and Treatment Regulations (9VAC25-790) for UV disinfection of secondary effluent.

B. Reclaimed water distribution system.

1. All reclaimed water distribution systems shall be designed and constructed in accordance with this chapter and applicable sections of the Sewage Collection and Treatment Regulations (9VAC25-790) pertaining to force mains, so that:

a. Reclaimed water does not come into contact with or otherwise contaminate a potable water system;

b. The structural integrity of the system is provided and maintained; and

c. The capability for inspection, maintenance, and testing is maintained.

2. For a reclaimed water distribution system, the following shall be implemented as part of the cross-connection and backflow prevention program submitted with the RWM plan:

a. There shall be no direct cross-connections between the reclaimed water distribution system and a potable water supply system.

b. The reclaimed water distribution system shall be in compliance with the cross connection control and backflow prevention requirements of Article 4 (12VAC5-590-580 et seq.) of Part II of the Commonwealth of Virginia Waterworks Regulations and, when applicable, the reclaimed water distribution system shall also be in compliance with the Virginia Statewide Building Code (13VAC5-63).

c. Potable water may be used to supplement reclaimed water for a reuse, provided there is an air gap separation of at least eight inches between the potable water and the reclaimed water or a reduced pressure principle backflow prevention device installed at the potable water service connection to the reuse. The installation of the reduced pressure principal backflow prevention device shall allow for proper inspection and testing of the device.

d. Reclaimed water shall not be returned to the reclaimed water distribution system after the reclaimed water has been delivered to an end user.

3. In-ground reclaimed water distribution pipelines shall be installed and maintained to achieve minimum separation distance and configurations as follows:

a. No reclaimed water distribution pipeline shall pass within 50 feet of a potable water supply well, potable water supply spring or water supply intake that are part of a regulated waterworks. The same separation distance shall be required between a reclaimed water distribution pipeline and a nonpublic or private potable water supply well or spring, but may be reduced to not less than 35 feet provided special construction and pipe materials are used to obtain adequate protection of the potable water supply.

b. Reclaimed water distribution pipeline shall be separated horizontally by at least 10 feet from a water main. The distance shall be measured edge-to-edge. When local conditions prohibit this horizontal separation, the reclaimed water distribution pipeline may be laid closer provided that the water main is in a separate trench or an undisturbed earth shelf located on one side of the reclaimed water distribution pipeline and the bottom of the water main is at least 18 inches above the top of the reclaimed water distribution pipeline. Where this vertical separation cannot be obtained, the reclaimed water distribution pipeline shall be constructed of water pipe material in accordance with AWWA specifications and pressure tested in place without leakage prior to backfilling. The hydrostatic test shall be conducted in accordance with the AWWA standard (ANSI/AWWA C600-05, effective December 1, 2005) for the pipe material, with a minimum test pressure of 30 psi.

c. Distribution pipeline that conveys Level 1 reclaimed water shall be separated horizontally by at least two feet from a sewer line. The distance shall be measured edge-to-edge. When local conditions prohibit this horizontal separation, the reclaimed water distribution pipeline may be laid closer provided that the sewer line is in a separate trench or an undisturbed earth shelf located on one side of the reclaimed water distribution pipeline and the bottom of the reclaimed water distribution pipeline is at least 18 inches above the top of the sewer line. Where this vertical separation cannot be obtained, either the reclaimed water distribution pipeline or the sewer line shall be constructed of water pipe material in accordance with AWWA specifications and pressure tested in place without leakage prior to backfilling. The hydrostatic test shall be conducted in accordance with the AWWA standard (ANSI/AWWA C600-05, effective December 1, 2005) for the pipe material, with a minimum test pressure of 30 psi.

d. Reclaimed water distribution pipeline shall cross under water main such that the top of the reclaimed water distribution pipeline is at least 18 inches below the bottom of the water main. When local conditions prohibit this vertical separation, the reclaimed water distribution pipeline shall be constructed of AWWA specified water pipe and pressure tested in place without leakage prior to backfilling, in accordance with the provisions of the Sewage Collection and Treatment Regulations (9VAC25-790). Where reclaimed water distribution pipeline crosses over water main, the reclaimed water distribution pipeline shall:

(1) Be laid to provide a separation of at least 18 inches between the bottom of the reclaimed water distribution pipeline and the top of the water main.

(2) Be constructed of AWWA approved water pipe and pressure tested in place without leakage prior to backfilling, in accordance with the provisions of the Sewage Collection and Treatment Regulations (9VAC25-790).

(3) Have adequate structural support to prevent damage to the water main.

(4) Have joints placed equidistant and as far as possible from the water main joints.

e. Sewer line shall cross under distribution pipeline that conveys Level 1 reclaimed water such that the top of the sewer line is at least 18 inches below the bottom of the reclaimed water distribution pipeline. When local conditions prohibit this vertical separation, the sewer line shall be constructed of AWWA specified water pipe and pressure tested in place without leakage prior to backfilling, in accordance with the provisions of the Sewage Collection and Treatment Regulations (9VAC25-790). Where sewer line crosses over distribution pipeline that conveys Level 1 reclaimed water, the sewer line shall:

(1) Be laid to provide a separation of at least 18 inches between the bottom of the sewer line and the top of the reclaimed water distribution pipeline.

(2) Be constructed of AWWA approved water pipe and pressure tested in place without leakage prior to backfilling, in accordance with the provisions of the Sewage Collection and Treatment Regulations (9VAC25-790).

(3) Have adequate structural support to prevent damage to the reclaimed water distribution pipeline.

(4) Have joints placed equidistant and as far as possible from the reclaimed water distribution pipeline joints.

f. No reclaimed water distribution pipeline shall pass through or come into contact with any part of a sewer manhole. Distribution pipeline that conveys Level 1 reclaimed water shall be separated horizontally by at least two feet from a sewer manhole whenever possible. The distance shall be measured from the edge of the pipe to the edge of the manhole structure. When local conditions prohibit this horizontal separation, the manhole shall be of watertight construction and tested in place.

4. No setback distance is required to any nonpotable water supply well and no vertical or horizontal separation distances are required between above-ground reclaimed water pipelines and potable water, sewer or wastewater pipelines.

5. All reclaimed water outlets shall be of a type, or secured in a manner, that permits operation by authorized personnel. Public access to reclaimed water outlets shall be controlled in areas where reclaimed water outlets are accessible to the public as follows:

a. If quick connection couplers are used on above-ground portions of the reclaimed water distribution system, they shall differ materially from those used on the potable water supply.

b. Use of above-ground hose bibs, spigots or other hand-operated connections that are standard on local potable water distribution systems shall be prohibited for use on the local reclaimed water distribution system. If above-ground hose bibs, spigots or other hand-operated connections are used on the reclaimed water distribution system, they must differ materially from those used on the local potable water distribution system and must be clearly distinguishable as reclaimed water connections (i.e., painted purple, valve operation with a special tool) so as not to be mistaken for potable water connections. Where below-grade vaults are used to house reclaimed water connections, the connections in the vault may have standard potable water distribution system thread and bib size services provided the bib valves can be operated only by a special tool. The below-grade vaults shall also be labeled as being part of the reclaimed water distribution system (i.e., painted purple, labeled).

6. Existing potable water distribution systems, sewer and wastewater collection systems, and irrigation distribution systems may be converted for use as reclaimed water distribution systems. Not less than 90 days prior to such conversions, excluding the conversion of irrigation distribution systems that are not under common ownership or management with reclamation systems, SRSs, or reclaimed water distribution systems providing reclaimed water to the irrigation distribution systems, the following shall be submitted to the board for approval:

a. A system conversion plan that contains:

(1) Information on the location and identification of the facilities to be converted;

(2) Information on the location of all connections to the facilities to be converted;

(3) A description of procedures to be used to ensure that all connections and cross-connections shall be eliminated. This may include physical inspections, dye testing, or other testing procedures;

(4) A description of the physical and operational modifications necessary to convert the existing system to a reclaimed water distribution system that shall comply with applicable design criteria in subsections B and C of this section, and the operations and maintenance requirements of 9VAC25-740-140 D 2;

(5) A description of cleaning and disinfection procedures to be followed before the converted facilities will be placed into operation for reclaimed water distribution. For the conversion of existing sewer and wastewater collection systems, cleaning and disinfection of the system shall be conducted in accordance with AWWA standards (ANSI/AWWA C651-05, effective June 1, 2005). Procedures to dispose of flush water from cleaning or disinfection shall be those described in the operations and maintenance manual of the system for the disposal of flush water from maintenance activities;

(6) An assessment of the physical condition and integrity of facilities to be converted; and

(7) Reasonable assurance that cross-connections will not result, public health will be protected, and the integrity of potable water, wastewater, and reclaimed water systems will be maintained when the conversion is made.

b. An operations and maintenance manual for the system converted to a reclaimed water distribution system in accordance with 9VAC25-740-140 B, containing at a minimum the items specified in 9VAC25-740-140 D.

7. Tank trucks may be used to transport and distribute reclaimed water only if the following requirements are met:

a. The truck is not used to transport potable water that is used for drinking water or food preparation;

b. The truck is not used to transport waters or other fluids that do not meet the requirements of this chapter, unless the tank has been evacuated and properly cleaned prior to the addition of the reclaimed water;

c. The truck is not filled through on-board piping or removable hoses that may subsequently be used to fill tanks with water from a potable water supply; and

d. The reclaimed water contents of the truck are clearly identified as nonpotable water on the truck.

8. Reclaimed water distribution systems shall have the following identification, notification and signage:

a. Reclaimed water piping with an outer diameter greater than or equal to one inch, installed in-ground after January 29, 2014, or above-ground shall display the words "CAUTION: RECLAIMED WATER - DO NOT DRINK" by one or more of the following methods:

(1) Stenciling or stamping the piping with two-inch to three-inch letters on opposite sides of the piping, placed at intervals of three to four feet. For piping less than two inches and greater than or equal to one inch outer diameter, lettering shall be at least 5/8 inch, placed on opposite sides of the piping and repeated at intervals of one foot.

(2) Wrapping the piping with purple (Pantone 522) polyethylene vinyl wrap or adhesive tape, placed longitudinally at three-foot intervals. The width of the wrap or tape shall be at least three inches, and shall display the required caution statement in either white or black lettering.

(3) Permanently affixing purple (Pantone 522) vinyl adhesive tape on top of the piping, parallel to the axis of the piping, fastened at least every 10 feet to each pipe section, and continuously for the entire length of the piping. The width of the tape shall be at least three inches, and shall display the required caution statement in either white or black lettering.

(4) Using an alternate method that assures the caution statement will be displayed to provide an equivalent degree of public notification and protection if approved by the board.

b. Additional methods, if provided, to identify reclaimed water piping with an outer diameter greater than or equal to one inch (e.g., permanently color coding the piping Pantone 522 purple), shall not obscure any portion of the caution statement required pursuant to subdivision 8 a of this subsection.

c. Reclaimed water piping with an outer diameter less than one inch shall require the following:

(1) Where installed in-ground after January 29, 2014, or above ground, the piping shall be permanently color coded purple (Pantone 522). Longitudinal purple striping of the piping may be allowed provided the cumulative width of the stripes is greater than or equal to 25% of the outer pipe diameter.

(2) Where installed within a building or structure, the piping shall have in addition to color coding required per subdivision 8 c (1) of this subsection, the words "CAUTION: RECLAIMED WATER – DO NOT DRINK" embossed, stenciled, stamped, or affixed with adhesive tape on the piping, placed on opposite sides of the piping, and repeated at intervals of one foot. Lettering of the caution statement shall be of a size easily read by a person with normal vision at a distance of two feet.

d. All other above-ground portions of the reclaimed water distribution system including reclaimed water valves, outlets (including fire hydrants) and other appurtenances shall be color coded, taped, labeled, tagged or otherwise marked to notify the public and employees that the source of the water is reclaimed water, not intended for drinking or food preparation. For reclaimed water treated to Level 2, such notification shall also inform employees to practice good personal hygiene for incidental contact with reclaimed water and the public to avoid contact with the reclaimed water.

e. Each mechanical appurtenance of a reclaimed water distribution system shall be colored purple and legibly marked "RECLAIMED WATER" to identify it as a part of the reclaimed water distribution system and to distinguish it from mechanical appurtenances of a potable water distribution system or a wastewater collection system.

f. Valve boxes for reclaimed water distribution systems shall be painted purple. Valve covers for reclaimed water distribution lines shall not be interchangeable with potable water supply valve covers.

g. Existing potable water distribution systems, sewer or wastewater collection systems, or irrigation distribution systems that are converted to reclaimed water distribution systems in accordance with subdivision 6 of this subsection after January 29, 2014, shall be retrofitted to meet identification, notification, and signage requirements of subdivision 8 of this subsection with the following exceptions:

(1) For converted systems requiring the submission of a conversion plan and an operations and maintenance manual in accordance with subdivision 6 of this subsection, existing in-ground converted piping shall be retrofitted to a distance of not less than 10 feet from locations where the piping crosses or is crossed by a potable water supply line or sanitary sewer line.

(2) For all other converted systems, identification, notification, and signage requirements specified in subdivision 8 of this subsection for in-ground piping shall not apply.

9. All reclaimed water distribution systems shall be maintained to minimize losses and to ensure safe and reliable conveyance of reclaimed water such that the reclaimed water will not be degraded below the standards, excluding CAT standards, required for the intended reuse or reuses in accordance with 9VAC25-740-90.

C. Storage requirements.

1. To ensure reliable reclamation system operation in accordance with the requirements of this chapter, all reclamation systems shall have the ability to implement one or more of the following options:

a. Store reclaimed water;

b. Discharge reclaimed water to another permitted reuse system, if applicable;

c. Discharge reclaimed water to surface waters of the state under a VPDES permit;

d. Suspend all or a portion of water reclamation for planned periods; or

e. In the case of a satellite reclamation system, discharge reclaimed water into the sewage collection system from which it received source water for reclamation.

2. Storage for reclaimed water shall be required only when subdivision 1 b, c, or d of this subsection or, as applicable, subdivision 1 e of this subsection are not available or approved by the board.

3. Separate, off-line storage shall be provided for reject water of the reclamation system unless the reject water can be diverted to another permitted reuse system, discharged to surface waters of the state under a VPDES permit, returned directly to an appropriate point of treatment in the reclamation system, or in the case of a satellite reclamation system, sent to the sewage collection system from which the reclamation system received water for reclamation. Where reject water is stored, provisions shall be incorporated into the design of the reclamation system to distribute the reject water from storage to other parts of the reclamation system for additional or repeated treatment.

4. Storage for reject water may also be used for emergency storage to ensure Reliability Class I of the reclamation system in accordance with 9VAC25-740-130.

5. Reject water and reclaimed water may be stored in watertight tanks placed above-ground or in-ground. Labeling of tanks used for reject water storage, system storage or nonsystem storage shall be in accordance with 9VAC25-740-160 B, and shall, at a minimum, identify the contents of each tank as either reject water or reclaimed water.

6. For all impoundments or ponds that are used for reject water storage or system storage, with the exception of impoundments and ponds specified in subdivision 7 of this subsection, the following are required:

a. A minimum two-foot freeboard shall be maintained at all times. Any emergency discharge or overflow device and the disposition of the overflow discharge shall be identified in the engineering report.

b. There shall be a minimum two-foot separation distance between the bottom of the impoundment or pond and the seasonal high water table.

c. The impoundment or pond shall have a properly designed and installed synthetic liner of at least 20 mils thickness or a compacted soil liner of at least one foot thickness. Synthetic liners shall be installed in accordance with the manufacturer's specifications and recommendations. The soil liner shall be composed of separate lifts not to exceed six inches. The maximum coefficient of permeability for the synthetic and soil liners shall not exceed 1x10^-6 cm/sec and 1x10^-7 cm/sec, respectively. A plan of quality assurance and quality control which substantiates the adequacy of the liner and its installation shall be included in or shall accompany the preliminary engineering report or supporting documentation for the CTC. Documentation of quality assurance and quality control activities on liner installation along with permeability test results, shall be submitted with the statement of construction completion to the board.

d. If the requirements of subdivision 6 b or c of this subsection cannot be met, the board may allow use of the impoundment or pond for storage provided that a groundwater monitoring plan for the facility is submitted to the board for review and approval. The plan shall identify the direction of groundwater flow and the proposed location and depth of groundwater monitoring wells at the location of the impoundment or pond, parameters to be monitored, a monitoring schedule, and procedures for proper sample collection and handling.

e. The design of the impoundment or pond shall prevent the entry of surface water or storm water runoff from outside the facility embankment or berm.

f. Where the embankment of the impoundment or pond is composed of soil, the embankment shall have:

(1) A top width of at least five feet;

(2) Interior and exterior slopes no steeper than one foot vertical to three feet horizontal unless alternate methods of slope stabilization are used;

(3) Shallow-rooted vegetative cover or other soil stabilization to prevent erosion; and

(4) Erosion stops and water seals installed on all piping that penetrates the embankment.

g. There shall be routine maintenance of the impoundment or pond liner, embankments and access areas.

h. Impoundments and ponds shall be sited to avoid areas of uneven subsidence, sinkholes, or unstable soils unless provisions are made for their correction. Results from field and laboratory tests from an adequate number of test borings and soil samples shall be the basis for computations pertaining to permeability and stability analyses.

i. Impoundments or ponds shall not be located on a floodplain unless protected from inundation or damage by a 100-year frequency flood event.

j. There shall be a minimum setback distance measured horizontally from the perimeter of the storage impoundment or pond to potable water supply wells and springs, and public water supply intakes, of 100 feet for storage of Level 1 reclaimed water and 200 feet for storage of Level 2 reclaimed water or reject water.

7. Reject water storage and system storage impoundments or ponds that exist upon October 1, 2008, shall be exempt from the design, construction, and operation requirements specified in subdivision 6 of this subsection until such time these facilities are modified or expanded, or unless they have failed to comply with other existing regulatory or permitting requirements.

8. The capacity of reject water storage and system storage facilities, including impoundments, ponds or tanks, shall be as follows:

a. For reject water, the capacity of the storage facility shall, at a minimum, be the volume equal to the designated design flow of the reclamation system unless other options exist for immediate disposal or retreatment of the reject water in addition to storage.

b. For reclaimed water, the capacity of the storage facility shall be determined by the seasonal variability in demand, intended reuses with intermittent, variable demand, such as fire protection or fighting; and the availability of other options to generate or manage reclaimed water as specified in subdivision 1 of this subsection.

(1) Where there is no or minimal seasonal variability in demand and no other options are available for alternative generation or management of all or a portion of the reclaimed water, the capacity of the storage facility shall, at a minimum, be the volume equal to three times that portion of the reclamation system designated design flow for which no other options to generate or manage the reclaimed water from the reclamation system are permitted.

(2) Where there is seasonal variability in demand and no other options are available for alternative generation or management of all or a portion of the reclaimed water during periods of low seasonal demand, storage facilities shall have sufficient storage capacity to assure the retention of the reclaimed water under conditions and circumstances that preclude reuse. The methods, assumptions and calculations used to determine the system storage requirements shall be provided and justified in the preliminary engineering report or supporting documentation for the CTC. Analytical means of determining system storage requirements, such as water balance calculations or computer hydrological programs, shall be used and shall account for all water inputs into the system. Analysis shall be based on site-specific data. Irrigation efficiencies or rainfall efficiencies shall not be used in storage volume determinations.

9. Requirements specified in subdivision 6 of this subsection shall not apply to impoundments or ponds used for nonsystem storage with the exception of those specified in subdivision 11 of this subsection.

10. Landscape impoundments may also be used for nonsystem storage of reclaimed water prior to another subsequent reuse, such as irrigation.

11. Impoundments or ponds used for nonsystem storage of reclaimed water, including landscape impoundments, for subsequent irrigation reuse on sites under common ownership or management with the reclamation system or satellite reclamation system that provides reclaimed water to the sites, shall comply with the design, construction and operation requirements specified in subdivision 6 of this subsection.

12. For impoundments or ponds used for nonsystem storage of reclaimed water, the following setback distances shall apply:

a. There shall be a 50-foot minimum setback distance measured horizontally from the perimeter of the impoundment or pond to property lines.

b. For an impoundment or pond with a liner meeting the requirements specified in subdivision 6 c of this subsection, there shall be a minimum setback distance measured horizontally from the perimeter of the storage impoundment or pond to potable water supply wells and springs, and public water supply intakes, of 100 feet for storage of Level 1 reclaimed water and 200 feet for storage of Level 2 reclaimed water.

c. For an unlined impoundment or pond, there shall be a minimum setback distance measured horizontally from the perimeter of the storage impoundment or pond to potable water supply wells and springs, and public water supply intakes, of 200 feet for storage of Level 1 reclaimed water and 400 feet for storage of Level 2 reclaimed water.

13. Where more than one setback distance applies to storage for reclaimed water or reject water, the greater setback distance shall govern.

14. Reclaimed water system storage facilities shall be designed and operated to prevent a discharge to surface waters of the state except in the event of a storm greater than the 25-year, 24-hour storm. Reclaimed water nonsystem storage facilities, including landscape impoundments used for nonsystem storage, shall be designed and operated to prevent a discharge to surface waters of the state, except in the event of a storm greater than the 10-year, 24-hour storm.

15. Permittees shall maintain current inventories of reject water storage, system storage and nonsystem storage facilities located within the service area of the RWM plan. An inventory or a revised inventory shall be submitted as part of the RWM plan in the permit application. For the addition of new storage facilities to an inventory after permit issuance, the permittee shall submit to the board an amended inventory at least 30 days before reclaimed water will be introduced into the new storage facilities. An inventory of reject water storage, system storage and nonsystem storage facilities shall include the following:

a. Name or identifier for each storage facility;

b. Location of each storage facility (including latitude and longitude);

c. Function of each storage facility (i.e., reject water storage, system storage or nonsystem storage);

d. Type of each storage facility (i.e., covered tank, uncovered tank, lined pond, unlined pond, etc.); and

e. Location (latitude and longitude) and distance of the nearest potable water supply well and spring, and public water supply intake, to each storage facility within 450 feet of that facility.

16. Storage requirements as specified in this subsection shall not apply to reclaimed water storage facilities provided at the site of an industrial end user where such facilities are regulated by an existing water permit issued by the board to the industrial end user, or the industrial end user is also the generator of reclaimed water stored in the facilities and is excluded under 9VAC25-740-50 A.

Historical Notes

Derived from Volume 24, Issue 26, eff. October 1, 2008; amended, Virginia Register Volume 30, Issue 09, eff. January 29, 2014.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.