Water/Sewer System Extension Review

Backflow Preventors

Locations and size of backflow preventors must be shown on the construction drawings. Backflow preventors are to be installed in accordance with the latest editions of the American Water Works Association (AWWA) Cross Connection Control Manual and the Uniform Plumbing code (UPC). If the backflow preventor is to be installed within a vault located on the exterior of the building, a detailed design must be included with the construction drawings delineating the vault layout, piping configuration, gravity drain and appurtenances.

Design Requirements for Water and
Sewer System Extensions

The booklet Design Requirements for Water and Sewer System Extensions, provides engineers, designers, draftsmen, inspectors and others with a reference of the City's requirements for the design and installation of improvements to the City's water and sewer systems. The Design Requirements booklet is currently pending revision, however current water/sewer design requirements can be found in Appendix 20D-4 of the Redmond Community Development Guide.

Fire Flow/Hydraulic Analysis

The desirable level of service for fire flow is 1,500 gpm for standard single-family residential areas of the City and 3,500 gpm in other areas such as commercial, industrial and multi-family housing. A hydraulic analysis to determine fire flow to a specific property is available for $238.00. For private development information contact Development Services 425-556-2844; for capital improvement project information contact Utility Engineering at 425-556-2873.

General Sewer Plan

The General Sewer Plan defines the current service area, sewer basins, and existing infrastructure, delineates the future sewer planning area, the projected service population, and resulting sewage flows; and then presents proposed improvements to upgrade existing facilities and provide sewer service to the Redmond area. Specific components of the plan include:

  • Service Area and System Characteristic
  • Planning Criteria
  • Sewer System Evaluation
  • Capital Improvement Program
  • Operations and Maintenance
  • Implementation

For further information, please contact Utility Engineering at 425-556-2873. The General Sewer Plan is available on CD to purchase for $20.00 plus tax.

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Grinder Pumps

Grinder pump applications are restricted to single-family and single commercial buildings that are physically unable to connect to the sanitary sewer system by gravity. For all applications, each grinder pump shall have its own individual force main.  Contact:  425-556-2876 

Pretreatment

Oil/Water Separators

Oil/water separators treat oily wastewater before the water is discharged to the sanitary sewer. Oil water separators are required for underground parking structures, gas stations, and for all facilities where there is potential for discharge of oily contaminated waters. In addition, no grease, oil, sand, liquid waste containing grease or flammable material or other harmful ingredients in excessive amount shall be discharged into any public sewer without installation of a pretreatment process. The design shall follow criteria established by the City and King County Wastewater Treatment Division.

Grease Interceptors

To ensure the proper disposal of animal fats and vegetable oils, and to prevent sewage back-ups, the City requires grease-generating establishments to correctly install, operate and maintain properly sized and designed grease interceptors. Grease interceptors shall be required for all commercial buildings with kitchen and/or cafeteria facilities. The sizing of the interceptor shall be in accordance with Appendix "H" of the latest edition of the Uniform Plumbing Code recognized by the City. Approval of the interceptor sizing by the Development Services Center is required prior to installation. Inspection of the grease interceptor shall be the responsibility of the Construction and/or Building Divisions. For permitting questions, sizing criteria, or other information:  Contact:  425-556-2431

Septic Tanks

There are still many parcels within the City that are currently serviced by septic tanks. If your site is currently serviced by a septic system, and you need information on location, etc., contact the King County Health Department at 206-296-4920. If you have questions regarding installation of sanitary sewer for replacement of your septic system, please contact the City of Redmond Development Services Center at 425-556-2876.   

Water System Plan

The purpose of the Water System Plan is to analyze the City's water system, recommending improvements to correct existing deficiencies and accommodate future service needs. The Plan provides a review of the current system and its operation, an analysis of projected demand, recommendations for system and operation improvements, as well as cost estimates and phasing of those improvements.

The Department of Social and Health Services (DSHS) requires the Water System Plan be updated every five years. The existing plan has been in effect since May 1992 and an update is currently underway and expected to be completed by early 2003. The Water System Plan will be available for purchase once the update is complete.

Contact:  425-556-2873

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Water/Sewer Service Area

Redmond Service Area

Roughly, the area east of 132nd Avenue N.E., south of N.E. 124th Street, west of 196th Avenue N.E., north of N.E. 20th Street, and specifically excluding Marymoor Park and Lake Sammamish.

Novelty Hill Service Area

The Novelty Hill Service Area is that area east of 196th Avenue N.E., south of Novelty Hill Road and east of 212th Avenue N.E., north of Novelty Hill Road.

Note: General parcel information for King County properties located in both incorporated and unincorporated areas can be obtained via the County's website. The Department of Development and Environmental Services (DDES) Parcel Locator displays this information in the form of maps, tables, and text allowing visitors to search for a property using a parcel number, a street address, or a street intersection.

Administrative Requirements/Miscellaneous

For additional details pertaining to forms, fees, bonds, or administrative requirements for developer utility system extensions.  Contact:  425-556-2840
 
From time to time, special appurtenances will be required for various development projects including, but not limited to grease interceptors, oil water separators, backflow preventors and grinder pumps.

Reimbursement Agreement

Portions of a system extension may benefit other properties and meet the criteria to be eligible for a reimbursement agreement. In order to be eligible for reimbursement, the City must have received a completed reimbursement agreement application prior to approval of construction drawings and the agreement must be fully executed by the City prior to commencement of construction of the facility. All reimbursement fees must be paid prior to sale of water and side sewer permits and may be required prior to plat or short plat recording.

SEPA Mitigations

Sewer System Study

As part of or in preparation for environmental documents for the project, an engineering report/sewer plan shall be prepared in accordance with Chapter 173-240 WAC, http://apps.leg.wa.gov/wac/default.aspx?cite=173-240. This report shall describe the sewer trunks and collectors needed to serve the project and other tributary areas.

The engineering document will need to be adopted by the City as part of its Utility Master Planning, either by Development Guide Amendment or Technical Committee approval, as appropriate. The engineering document will need to be reviewed and approved by the applicable State and local agencies.

Water System Study

As part of or in preparation for environmental documents for the project, a water system plan/project report shall be prepared in accordance with Chapter 248-54 WAC, http://apps.leg.wa.gov/wac/default.aspx?cite=246-293-230. This report shall describe water transmission/distribution mains and appurtenances needed to serve the project and other proximate areas.

The engineering document will need to be adopted by the City as part of its Utility Master Planning either by Development Guide Amendment or Technical Committee approval, as appropriate. The engineering document will need to be reviewed and approved by the applicable State and local agencies.

Fees

Plan review and construction inspection fees are required and will be at the rate in effect when plans are approved. Connection fees are at the rate in effect when water meter and side sewer permits are issued. All reimbursement fees shall be paid prior to sale of water and side sewer permits. Reimbursement fees may be required prior to plat or short plat recording. Contact the Development Services of the Public Works Department to obtain an estimate of the fees that will apply.

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Additional Information

Water/Sewer System Extension Review

Contact
Development Services Center
425-556-2760