(A) Professional engineer required. The plans for all water lines, booster stations and the like shall be designed, signed and sealed by a registered professional engineer licensed in the state.
(B) Compliance. All water lines, booster stations and the like shall be designed in accordance with the state’s Department of Environmental Quality requirements.
(C) Minimum size. Minimum water main size shall be six-inch diameter. Larger sizes shall be as required by the city’s overall water system master plan or as are needed to provide adequate water-carrying capacity for the area (and surrounding developable area) being developed and/or annexed to the city. Minimum building service line size shall be three-fourths inch in diameter.
(D) Materials.
(1) Pipe, fittings, valves and fire hydrants shall conform to the latest standards issued by the AWWA, if such standards exist, and be acceptable to the city. In the absence of such standards, materials meeting applicable product standards and acceptable to the city may be selected. Special attention shall be given to selecting pipe materials which will protect against both internal and external pipe corrosion.
(2) Packing and jointing materials used in the joints of pipes shall meet the standards of the AWWA and the city. Pipe having mechanical joints or slip-on joints with rubber gaskets is preferred.
(E) Water main design.
(1) Pressure. All water mains, 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 at ground level at all points in the distribution system under all conditions of flow. The normal working pressure in the distribution system should be approximately 60 psi and not less than 35 psi.
(2) Diameter. The minimum size of water main for providing fire protection and serving fire hydrants shall be six-inch diameter. Larger size mains will be required if necessary to allow the withdrawal of the required fire flow while maintaining the minimum residual pressure specified in division (E)(1) above.
(3) Fire protection. When fire protection is to be provided, system design should be such that fire flows and facilities are in accordance with the requirements of the state’s Insurance Services Office.
(4) Small mains. Any departure from minimum requirements shall be justified by hydraulic analysis and future water use, and can be considered only in special circumstances.
(5) Hydrants. Water mains not designed to carry fireflows shall not have fire hydrants connected to them.
(6) Dead ends. Dead ends shall be minimized by looping of all mains whenever practical.
(7) Flushing. Where dead-end mains occur, they shall be provided with a fire hydrant if flow and pressure are sufficient, or with an approved flushing hydrant or blow-off for flushing purposes. Flushing devices should be sized to provide flows which will give a velocity of at least two and five-tenths feet per second in the water main being flushed. No flushing device shall be directly connected to any sewer.
(F) Valves. Sufficient valves shall be provided on water mains so that inconvenience and sanitary hazards will be minimized during repairs. Valves should be located at not more than 500-foot intervals in commercial districts and at not more than one block or 800-foot intervals in other districts.
(G) Hydrants.
(1) Location and spacing. Hydrants should be provided at each street intersection and at intermediate points between intersections as recommended by the state’s Insurance Service Office. Generally, hydrant space may range from 350 feet to 600 feet depending on the area being served.
(2) Valves and nozzles. Fire hydrants should have a bottom valve size of at least five inches, one pumper nozzle of four and one-half inches and two nozzles of two and one-half inches.
(3) Hydrant leads. The hydrant shall be a minimum of six inches in diameter. Auxiliary valves shall be installed in all hydrant leads.
(4) Drainage. Hydrant drains should be open. A gravel pocket or dry well shall be provided unless the natural soils will provide adequate drainage. Hydrant drains shall not be connected to or located within ten feet of sanitary sewers or storm drains.
(H) Air relief valves; valve, meter and blow-off chamber.
(1) Air relief valves. At high points in water mains where air can accumulate, provisions should be made to remove the air by means of hydrants or air relief valves. Automatic air relief valves shall not be used in situations where flooding of the manhole or chamber may occur.
(2) Air relief valve piping. The open end of an air relief pipe from automatic valves should be extended to at least one foot above grade and provided with a screened, downward-facing elbow. The pipe from a manually-operated valve should be extended to the top of the pit.
(3) Chamber drainage. Chambers, pits or manholes containing valves, blow-offs, meters or other such appurtenances to a distribution system, shall not be connected directly to any storm drain or sanitary sewer, nor shall blow-offs 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.
(I) Installation of mains.
(1) Standards. Specifications shall incorporate the provision of the AWWA standards and/or manufacturer’s recommended installation procedures.
(2) Bedding. A continuous and uniform bedding shall be provided in the trench for all buried pipe. Backfill material shall be tamped in layers around the pipe and to a sufficient height above the pipe to adequately support and protect the pipe. Stones found in the trench shall be removed to a depth of at least six inches below the bottom of the pipe.
(3) Cover. In general, water lines shall be sufficiently deep so as to provide frost protection. Water lines shall have at least six feet of cover (from the top of water line pipe to the ground or street surface) unless a special design is approved by the Public Works Superintendent.
(4) Blocking. All tees, bends, plugs and hydrants shall be provided with reaction blocking, tie rods or joints designed to prevent movement.
(5) Pressure and leakage testing. All types of installed pipe shall be pressure tested and leakage tested in accordance with the latest edition of AWWA Standard C600.
(6) Disinfection. All new, cleaned or repaired water mains shall be disinfected in accordance with AWWA Standard C601. The specifications shall include detailed procedures for the adequate flushing, disinfection and microbiological testing of all water mains.
(J) Separation of water mains, sanitary sewers and storm sewers.
(1) General. The following factors should be considered in providing adequate separation:
(a) Materials and type of joints for water and sewer pipes;
(b) Soil conditions;
(c) Service and branch connections into the water main and sewer line;
(d) Compensating variations in the horizontal and vertical separations;
(e) Space for repair and alterations of water and sewer pipes; and
(f) Off-setting of pipes around manholes.
(2) Parallel installation. Water mains shall be laid at least ten feet horizontally from any existing or proposed sewer. The distance shall be measured edge to edge. In cases where it is not practical to maintain a ten foot separation, the reviewing authority may allow deviation on a case-by-case basis, if supported by data from the design engineer. Such deviation may allow installation of the water main closer to a sewer; provided, that the water main is laid in a separate trench or on an undisturbed earth shelf located on one side of the sewer at such an elevation that the bottom of the water main is at least 18 inches above the top of the sewer.
(3) Crossings. Water mains crossing sewers shall be laid to provide a minimum vertical distance of 18 inches between the outside of the water main and the outside of the sewer. This shall be the case where the water main is either above or below the sewer. At crossings, one full length of water pipe shall be located so both joints will be as far from the sewer as possible. Special structural support for the water and sewer pipes may be required.
(4) Exception. The city must specifically approve any variance from the requirements of divisions (J)(2) and (J)(3) above when it is impossible to obtain the specified separation distances.
(5) Force mains. There shall be at least ten-foot horizontal separation between water mains and sanitary sewer force mains. There shall be an 18-inch vertical separation at crossings as required in division (J)(3) above.
(6) Sewer manholes. No water pipe shall pass through or come in contact with any part of a sewer manhole.
(K) Surface water crossings. Surface water crossings, whether over- or under-water, present special problems. The reviewing authority should be consulted before final plans are prepared.
(1) Above-water crossing. The pipe shall be adequately supported and anchored, protected from damage and freezing and accessible for repair or replacement.
(2) Under-water crossings. A minimum cover of five feet shall be provided over the pipe. When crossing watercourses which are greater than 15 feet 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 in a manhole.
(c) Permanent taps shall be made on each side of the valve within the manhole to allow insertion of a small meter to determine leakage and for sampling purposes.
(L) Cross-connections and interconnections.
(1) Cross-connections. There shall be no connection between the distribution system and any pipes, pumps, hydrants or tanks whereby unsafe water or other contaminating materials may be discharged or drawn into the system.
(2) Cooling water. Neither steam condensate nor cooling water from engine jackets or other heat exchange devices shall be returned to the potable water supply.
(M) Water services and plumbing.
(1) Plumbing. Water services and plumbing shall conform to relevant local and/or state plumbing codes.
(2) Booster pumps. Individual booster pumps shall not be allowed for any individual service from the public water supply mains.
(N) Location of water lines and storm drains. Sanitary water lines and water lines shall, wherever possible, be located on opposite sides of the street. Preferably, water lines shall be located 13 feet west or north of the street center line and the sanitary water at 13 feet east or south of the street center line. When storm drains are needed, these shall preferably be located along the street center line. The locations and dimensions referenced in this division (N) may be varied to accommodate unusual circumstances.
(O) Requirements for drawings. All drawings shall be on linen or Mylar in ink and of such quality that they clearly show the dimensions, locations, sizes and the like of all facilities represented thereon. All main lines, valves, fire hydrants, building service lines and the like shall be clearly shown and identified by name and by station or other means of horizontal location. Water lines shall be shown in both plan and profile unless the length of this water line or water line extension is so short that the Public Works Superintendent waives this requirement. If a profile of the water line is not provided, it shall be located in the vertical plane by elevations on the flow line of the pipe at intervals as the Public Works Superintendent may require. Drawings shall be drawn on a scale of one inch equals 50 feet unless the amount of detail, topography and the like necessitate their being drawn on a larger scale (i.e., one inch equals 30 feet) to provide the clarity and completeness needed on the drawings.
(P) Approval of design. The design of all water lines and water line plans must be approved by the Public Works Superintendent.
(Prior Code, § 8-1-25) (Ord. 92-549, passed 3-18-1992; Ord. 15-811, passed 11-19-2015)