2.2 General Design Considerations

  1. In all residential and commercial developments, water main extensions are required to assure orderly development of the water utility system by complying with the PUD’s requirements for development, water quality, pressure zones, and fire protection.
  2. Design and construction of water mains, including but not limited to mainlines, valving, fire hydrants, fire sprinkler connections with backflow devices, domestic and irrigation services, pump stations, pressure reducing stations, telemetry and other appurtenances shall be in compliance with PUD ordinances, special requirements of the PUD, these standards, and the most recent version of the Standard Specifications for Road, Bridge, and Municipal Construction (Standard Specifications) as produced by the Washington State Department of Transportation.
  3. The applicant is responsible for designing the proposed water system(s). The system(s) must be designed by an engineer licensed in the State of Washington and approved by PUD.
  4. Main line pressure reducing devices are to be designed, constructed, and paid for by the applicant and approved by PUD.
  5. Pressure reducing valves on individual services may be required at the discretion of the PUD. Such valves will be installed after the meter and will be the responsibility of the homeowner to install and maintain.
  6. Customer owned booster pumps may be allowed on a case-by-case basis provided they satisfy the design and construction standards. The maximum capacity of the booster pump shall be sized at 50 percent of the rated capacity of the water meter. The customer shall provide sufficient information on the pump to the PUD indicating the capacity and that it satisfies this criterion. A backflow device is required between the meter and the booster pump.
  7. The developer shall be responsible for ensuring that water system pressures associated with the proposed water system extension meet the criteria described in Section 3.1, and shall provide documentation showing as such. At the sole discretion of the PUD, the developer may be required to perform hydraulic modeling of the existing / proposed water system to ensure minimum system pressures are maintained under high water demand scenarios. If hydraulic modeling is required, the PUD will provide a digital files in WaterCAD format to the developer. The developer shall then submit an updated model to the PUD in WaterCAD format showing that minimum water system pressures will be maintained under high water demand scenarios. The revised hydraulic model will be reviewed by a third-party engineering firm selected by the PUD. Alternatively, the developer may pay for such modeling to be performed directly by a third-party engineering firm selected by the PUD. In either instance, all costs associated with the hydraulic modeling / review shall be borne by the developer.