(a) Materials. - (i) Types of commercial pipe approved for water systems include:
- (A) PVC water pipe: ASTM D2241, less than 4" diameter (10 cm); AWWA C900: 4" (10 cm) and larger diameter.
- (B) Asbestos cement pressure pipe: AWWA C400.
- (C) Ductile iron pipe: AWWA C151.
- (D) Glass fiber - reinforced thermosetting - resin pressure pipe: AWWA C950.
- (E) Polyethelyene: AWWA C901.
- (F) Polybutelyene: AWWA C902.
- (ii) Used materials. Watermains and valves which have been used previously for conveying potable water may be reused provided they are in good working order and can meet these standards. No other used materials may be employed.
- (iii) Joints. Packing and jointing materials used in the joints of pipe shall be flexible and durable. Flanged piping shall not be used for buried service except for connections to valves; push-on or mechanical joints shall be used.
- (iv) Service connections. Service connections shall mean and include any water line or pipe connected to a distribution supply main or pipe for the purpose of conveying water to a building or dwelling. All service connections shall be constructed in conformance with the Uniform Plumbing Code.
(b) Watermain design. - (i) Pressure. All watermains, including those not designed to provide fire protection, shall be sized after a hydraulic analysis based on flow demands and pressure requirements. The system shall be designed to maintain a minimum pressure of 20 psi (138 kPa) at ground level at all points in the distribution system under all conditions of flow. The normal working pressure in the distribution system shall be not less than 35 psi (276 kPa).
- (ii) Diameter. The minimum size of a watermain for providing fire protection and serving fire hydrants shall be 6 inches (0.15 m) diameter when service is provided from 2 directions, or where the maximum length of 6 inches pipe serving the hydrant from 1 direction does not exceed 250 feet, or 8 inches (0.2 m) where service is provided from 1 direction only. Larger size mains shall be provided as necessary to allow the withdrawal of the required fire flow while maintaining the minimum residual pressure of 20 psi (138 kPa).
- (iii) Fire protection. When fire protection is to be provided, system design shall be such that fire flows can be served.
- (iv) Small mains. Any main smaller than 6 inches (0.15 m) shall be justified by hydraulic analysis and future water use.
- (v) Hydrants. Only watermains designed to carry fire flows shall have fire hydrants connected to them.
- (vi) Deadends. Deadends shall be minimized by looping.
- (vii) Flushing. Where deadend mains occur they shall be provided with a flushing hydrant or blowoff for flushing purposes. Flushing devices shall be sized to provide flows which will give a velocity of 2.5 feet per second minimum in the watermain being flushed. No flushing device shall be directly connected to any sewer.
(c) Valves. Valves shall be provided on watermains so that inconvenience and sanitary hazards will be minimized during repairs. Valves shall be located at not more than 500 foot (152 m) intervals in commercial districts and at not more than 1 block or 800 foot (244 m) intervals in other districts.
(d) Hydrants. - (i) Hydrant leads. The hydrant lead shall be a minimum of 6 inches (0.15 m) in diameter. Valves shall be installed in all hydrant leads.
- (ii) Protection from freezing. Provisions shall be made to protect fire hydrant leads and barrels from freezing. The use of hydrant weep holes is not allowed when groundwater levels are above the gravel drain area. In these cases it will be necessary to pump the hydrant dry or use other means of dewatering.
- (iii) Drainage. Hydrant drains shall not be connected to or located within 10 feet (3.05 m) of sanitary sewers or storm drains.
(e) Air relief valves; Valve, meter and blowoff chambers. - (i) Air relief valves. In all transmission lines and in distribution lines 16 inches and larger at high points (where the water pipe crown elevation falls below the pipe invert elevation), provisions shall be made for air relief. Fire hydrants or active service taps may be substituted for air relief valves on 6- and 8-inch lines. Manholes or chambers for automatic air relief valves shall be designed to prevent submerging the valve with groundwater or surface water.
- (ii) Chamber drainage. Chambers, pits or man-holes containing valves, blowoffs, meters, or other such appurtenances to a distribution system, shall not be connected directly to any storm drain or sanitary sewer, nor shall blowoffs or air relief valves be connected directly to any sewer. Such chambers or pits shall be drained to the surface of the ground where they are not subject to flooding by surface water or to absorption pits underground. Where drainage cannot be provided, a sump for a permanent or portable pump shall be provided.
(f) Excavation, bedding, installation, backfill. - (i) Excavation. The trench bottom shall be excavated for the pipe bell. All rock shall be removed within 6 inches (15.2 cm) of the pipe. The trench shall be dewatered for all work.
- (ii) Bedding. Bedding shall be designed in accordance with ASTM C12 -types A, B, C - for rigid pipe and ASTM D2321 - types I, II, III - for flexible pipe.
- (iii) Installation. The pipe shall be joined to assure a watertight fitting. Ductile iron pipe shall be installed in accordance with AWWA 600 and PVC piping shall be installed in accordance with AWWA manual M23.
- (iv) Backfill. Backfill shall be performed without disturbing pipe alignment. Backfill shall not contain debris, frozen material, unstable material, or large clods. Stones greater than 3 inches (7.6 cm) in diameter shall not be placed within 2 feet (0.6 m) of pipe. Compaction shall be to a density equal to or greater than the surrounding soil.
- (v) Cover. All watermains shall be located to protect them from freezing and frost heave.
- (vi) Blocking. All tees, bends, plugs, and hydrants shall be provided with reaction blocking, tie rods, or joints designed to prevent movement.
- (vii) Pressure and leakage testing. All types of installed pipe shall be specified to be pressure tested and leakage tested in accordance with AWWA Standard C600.
- (viii) Disinfection. All new, cleaned, repaired, or reused watermains shall be specified to be disinfected in accordance with AWWA Standard C601. Specifications shall include detailed procedures for the adequate flushing, disinfection, and microbiological testing of all watermains.
(g) Separation of watermains, sanitary sewers and storm sewers. - (i) Horizontal and vertical separation from sewer lines. Minimum horizontal separation shall be 10 feet (3 m) where the invert of the watermain is less than 1.5 feet (0.46 m) above the crown of the sewer line. Minimum vertical separation shall be 1.5 feet (0.46 m) at crossings. Joints in sewers at crossings shall be located at least 10 feet (3 m) from water mains. The upper line of a crossing shall be specially supported. Where vertical and/or horizontal clearances cannot be maintained, the sewer or water line shall be placed in a separate conduit pipe.
- (ii) Sewer manholes. No water pipe shall pass through or come in contact with any part of a sewer manhole.
(h) Surface water crossings. - (i) Above water crossings. The pipe shall be adequately supported and anchored, protected from damage and freezing, and accessible for repair or replacement.
- (ii) Underwater crossings. A minimum cover of 2 feet (0.61 m) shall be provided over the pipe. When crossing water courses which are greater than 15 feet (4.6 m) in width, the following shall be provided:
- (A) The pipe shall be of special construction, having flexible watertight joints.
- (B) Valves shall be provided at both ends of water crossings so that the section can be isolated for testing or repair; the valves shall be easily accessible and not subject to flooding; and the valve closest to the supply source shall be located in a manhole.
(i) Cross-connections. - (i) Cross-connections. There shall be no water service connection installed or maintained between a public water supply and any water user whereby unsafe water or contamination may backflow into the public water supply.
- (A) Applicability. In order to protect all public water supplies from the possibility of the introduction of contamination due to cross connections, the water supplier shall require backflow prevention devices for each water service connection in accordance with Table 1 which appears at the end of this section, with the exception of (B)(I) residential water service connections and (B)(II) domestic non-residential water service connections. The water supplier shall take appropriate actions which may include immediate disconnection for any water user that fails to maintain a properly installed backflow prevention device or comply with other measures as identified in Section 14(i) of these regulations.
- (I) Any high hazard non-residential connection to any public water supply shall be protected by the appropriate backflow prevention device.
- (II) Any service connection made to facilities constructed under a permit to construct issued after adoption of this regulation, Section 14(i), shall be in full compliance with this section. This requirement applies to all service connections made or initially activated after the adoption of this regulation.
- (III) Water suppliers shall establish record keeping and management procedures to ensure that requirements of this regulation for installation and maintenance of backflow prevention devices are being met.
- (B) The method of backflow control, selected from Table 1, shall be determined based upon the degree of hazard of the cross connection and the cause of the potential backflow. Hazards shall be classified as high hazard or low hazard. The potential cause of the backflow shall be identified as being back-siphonage or back-pressure.
- (I) Residential water service connections shall be considered to be low hazard back-siphonage connections, unless determined otherwise by a hazard classification.
- (II) Domestic non-residential water service connections shall be considered to be low hazard back-pressure connections, unless determined otherwise by a hazard classification conducted by the water supplier. Examples include schools without laboratories, churches, office buildings, warehouses, motels, etc.
- (III) Any water user's system with an auxiliary source of supply shall be considered to be a high hazard, back pressure cross connection. A reduced pressure principle backflow device shall be installed at the water service connection to any water user's system with an auxiliary source of supply.
- (IV) All water loading stations shall be considered high hazard connections. A device, assembly, or method consistent with Table 1 shall be provided.
- (V) Non-domestic commercial or industrial water service connections shall be considered to be high hazard back pressure connections, unless determined otherwise by a hazard classification. Examples include restaurants, refineries, chemical mixing facilities, sewage treatment plants, mortuaries, laboratories, laundries, dry cleaners, irrigation systems, facilities producing or utilizing hazardous substances, etc. For some of these service connections, a hazard classification may result in a determination of a back-siphonage or low hazard classification. The backflow prevention device required shall be appropriate to the hazard classification. Where potential high hazards exist within the non-residential water user's system, even though such high hazards may be isolated at the point of use, an approved backflow prevention device shall be installed and maintained at the water service connection.
- (C) Determination of the hazard classification of a water service connection is the responsibility of the water supplier. The water supplier may require the water user to furnish a hazard classification survey to be used to determine the hazard classification.
- (D) Hazard classifications shall be conducted by hazard classification surveyors that are certified by the USC-Foundation for Cross-Connection Control and Hydraulic Research, the American Association of Sanitary Engineers (ASSE), or by another state certification program approved by the administrator, or by a water distribution system operator also certified as a backflow device tester employed by the public water supplier for the service where the survey is being conducted.
- (E) All backflow prevention devices must be in-line serviceable (repairable), in-line testable except for devices meeting ASSE Standard #1024, and installed in accordance with manufacturer instructions and applicable plumbing codes.
- (F) All backflow prevention devices must have a certification by an approved third party certification agency. Approved certification agencies are:
- (I) American Society of Sanitary Engineers (ASSE),
- (II) International Association of Plumbing/Mechanical officials (IAPMO), and
- (III) Foundation for Cross-Connection Control and Hydraulic Research, University Of Southern California (USC_FCCCHR).
- (G) Backflow prevention devices at water service connections shall be inspected and certified by a certified backflow assembly tester at the time of installation. Certification of the assembly tester shall be by one of the following:
- (I) The American Society Sanitary Engineers (ASSE),
- (II) American Backflow Prevention Association (ABPA),
- (III) A state certification program approved by the administrator.
- (H) Backflow prevention devices installed at high hazard non-residential cross connections shall be inspected and tested on an annual basis by a certified backflow assembly tester.
- (I) The administrator may conduct inspections of backflow prevention devices. If any device is found to be defective or functioning improperly, it must be immediately repaired or replaced. Failure to make necessary repairs to a backflow prevention device will be cause for the water service connection to be terminated.
- (J) All public water suppliers shall report any high hazard backflow incident within seven (7) days to the Wyoming Department of Environmental Quality, Water Quality Division. The backflow incident shall be reported on a form provided by the administrator.
- (ii) Recycling water. Neither steam condensate nor cooling water from engine jackets or other heat exchange devices shall be returned to the public water supply after it has passed through the water service connection.
TABLE 1
Backflow Prevention Devices, Assemblies and Methods
| Degree of Hazard | |
| Device, Assembly or Method | Low Hazard | High Hazard | Notes |
| Back-Siphonage | BackPressure | Back-Siphonage | BackPressure |
| Airgap | X | | X | | See Note 1 |
| Atmospheric Vacuum Breaker | X | | X | | Not allowed under continuous pressure |
| Spill-proof Pressure-type Vacuum | X | | X | | |
| Double Check Valve Backflow Preventer | X | X | | | |
| Pressure Vacuum Breaker | X | | X | | |
| Reduced Pressure Principle Backflow | X | X | X | X | See Note 2 |
| Dual Check | X | | | | Restricted to residential services |
Note 1 Minimum Airgap for Water Distribution. For spouts with an effective opening diameter of one-half inch or less, the minimum airgap when the discharge is not affected by side walls shall be one inch. The minimum airgap when the discharge is affected by sidewalls shall be one and one-half inches. For effective openings greater than one-half inch, the minimum airgap shall be two times the effective opening diameter when the discharge is not affected by side walls. The minimum airgap when the discharge is affected by sidewalls shall be three times the effective opening diameter.
Note 2 Extreme Hazards. In the case of any water user's system where, in the opinion of the water supplier or the administrator, an undue health threat is posed because of the presence of extremely toxic substances or potential back pressures in excess of the design working pressure of the device, the water supplier may require an air gap at the water service connection to protect the public water system.
020-12 Wyo. Code R. § 12-14