Installing Water Mains

A water main extension (WME) or system improvement will be required if a parcel requesting new water service does not abut a standard distribution or suitable water main. For information on water availability, see CAM 1201. SPU will issue an approved or unapproved WAC based on your project’s specific site conditions. You will be required to enter into a water system improvement contract to design and construct the water main system improvement if your project is issued an unapproved WAC.

Water main contracting & construction process

Contract initiation phase

1. Contact the DSO when you are ready to initiate the required water system improvements. The DSO can be reached at (206) 684-3333 or
2. SPU will assign a project lead for the lifecycle of your project.
3. Your project lead will draft a commitment contract and prepare the invoice for the commitment contract charges.
4. SPU will issue an approved WAC when the contract is fully executed and the invoice is paid.

Design review phase

1. The design review process for a WME project differs on whether it is located within or outside the City of Seattle. If the project is located within Seattle, the design review process is led by the Seattle Department of Transportation (SDOT) through their street use permit process. The design review process is led by the DSO if the project is located outside of Seattle. Both reviews may require reviews at 30%, 60% and 90% design completion based on project complexity.
2. The property owner will work with SPU directly to develop a 30% Alignment Design for the WME requirement and appurtenances.
3. Once review cycles are complete and the plan is approved, SPU and SDOT will sign the mylars.

Pre-construction phase

Your assigned project lead will send you the following documents:

  • A pre-construction meeting notice form.
  • A transfer of ownership form.

You must fill these forms out and return them to your project lead.

Construction phase

1. Your project lead will prepare the construction contract and the invoice for related fees once the project is at 90% design.
2. Once your project is at 100% approved design a SPU resident engineer will invite all applicable representatives to the pre-construction meeting.
3. Please allow 10 business days for the meeting to be held after you’ve submitted the pre-construction meeting notice document to your SPU project lead.
4. The SPU resident engineer will guide the project through construction and to completion.

Reconciliation phase

The SPU WME construction contract is a time and materials charge. SPU reconciles all time and material fees when construction is complete. SPU will send the property owner a bill for additional fees or issue a refund after project completion.