Standard Specification 1-07
Standard Specification 9-30
Standard Specification 7-10.3(5)C
Standard Specification 7-11
Standard Plan 030: Standard Locations for Utilities (Residential Street)
Standard Plan Section 300: Watermain Appurtenances
Standard Plan 286a and 286b: Sewer and Water Spacing and Clearances
Standard Plan 330a and 330b: Water Main Thrust Blocking Vertical Fittings

Water main design and pre-design meeting: SPU Engineering provides design criteria for water mains at a required pre-design meeting that will be scheduled by SPU Customer Service.

SPU and other agencies may stipulate conformance to water main requirements and to other utilities. For the purpose of uniformity all projects will require a DPD Master Use Permit (MUP) application. Also, the Applicant should contact Seattle Public Utilities staff for anticipated work within the right-of-way that may impact existing water mains or water facilities.

Protection of existing facilities: special measures to protect existing or proposed facilities may be required depending on scope and impact of the proposed water main project. Special protection measures may include but not exclusively the use of restrained joint pipe, corrosion protection, and construction methods.

Water main plans and submittals: The plans for water mains and appurtenances shall show:

• all appropriate physical features adjacent to the proposed water mains;
• horizontal and vertical controls;
• hydrant coverage; and
• other utilities such as gas mains, sanitary and storm sewers, manholes, etc, including horizontal and vertical separation distances.

Design details for other utilities that do not affect the water main will not be shown on water main plans. Refer to the SPU CADD standards.

The Project Engineer must show that all water main projects meet the requirements and that evidence of approval be provided to the jurisdiction in charge.

Pipe material: All materials for water distribution shall be new and conform to Standard Specifications Section 9-30.

Standard location for water mains within the public right-of-way: Water mains will be generally located on the north and east side of the public right-of-way, or as approved by the SPU Engineer. In the event that the standard location for water mains is not available SPU Engineering will provide guidance in the best alignment available.

Water valves: Water valves will generally be placed aligned with the perpendicular right-of-way margins, as shown in Figure 4-22: Typical Valve Location. If this location is otherwise unavailable SPU Engineering will appoint the alternative position. SPU Engineering will approve the final location for all water components constructed in the City right-of-way.

Water main, sewer and other utilities separation: Water mains and water service lines shall be protected from the following:

• sanitary sewers;
• storm sewers;
• combined sewers;
• house sewer service connections;
• drains;
• sanitary sewer force mains; and
• other utilities.

Spacing between water mains and other utilities should comply with City of Seattle Standard Specifications 1-07, and Standard Plans 286a and 286b.

Depth of pipe cover: All pipe shall be laid to a minimum depth as indicated in Standard Specification 7-10.3(5)C and Standard Plan No. 030.

Thrust block: Provide concrete thrust blocks at points where piping changes directions or at dead ends. Thrust blocks shall be designed and installed as indicated in Standard Specification 7-11. Also, thrust blocks must conform to Standard Plan Nos. 330a and 330b.

For pipes larger than 12 inch diameter, and where water pressures are higher and/or soil conditions are poor, the developer engineer shall design the correct block size. All thrust block designs will require the approval of SPU Engineering prior to installation. The stamped calculations shall be submitted to SPU Engineering for review and approval.

Test pressure for field testing water main pipe: Field pressure testing for water mains shall be in accordance with Standard Specification 7-11. Field hydrostatic testing of various diameter ductile iron water main pipes and appurtenances shall be:

Test Pressure for Field Testing Water Main Pipes

Flushing and disinfection: Before being placed in service all newly installed pipes, valves, hydrants and appurtenances shall be flushed, disinfected and kept clean, and an acceptable bacteriological report shall be obtained. Flushing and purification shall be in accordance with Standard Specification 7-11.

Vault location: Prior to water service approval, SPU Customer Service shall coordinate all work associated with installation of service vaults. The table below provides some preliminary information. SPU Water Crews will perform all service work.

Water services: For further inquiries regarding water services please contact SPU Engineering or SPU Customer Service.

• Get more information on water service standard charges
• Get more information on metering
• Get more information on drinking water rates

Vault Location by Meter Size and Type

• Consider how to maintain fire flow during construction activities.
• Coordination with SPU water operations is required for all new connections, services, meter installations and any temporary cut and caps or temporary mains to facilitate your construction.
• Provide notice to the Fire Department if flow will be impeded and what provisions have been made – also note if access at the site will be limited or if street access will be limited.
• Be sure to check for utilities in the project alignment especially around large service locations as they could interfere with water mains, blocking, or meter vault installations.
• Only SPU crews are allowed to operate the existing water system for public health and safety reasons. Plan to coordinate with SPU water crews well in advance of starting construction to have your work added to crew work schedules.