Seattle Public Utilities Mami Hara, General Manager/CEO

Apply for a Water Availability Certificate

Client Assistance Memo 1201

Check for water availability before developing a property

Before developing a property in the City of Seattle or an SPU-direct water service area, verify that water service is available for the parcel. To determine if your parcel has adequate water service and that there is a water main serving the parcel, request a water availability certificate (pdf) from SPU. You can also do your own preliminary research online using the Development Services Office Research Map.

Don’t assume that each property has access to water. Just because other properties in an area have existing water service doesn’t mean that adequate water service is available to your property. In some cases, you might have to make significant improvements to the existing infrastructure to obtain additional service. Examples include extending a standard water main, installing a fire hydrant, or adding other water infrastructure.

What is a water availability certificate?

SPU issues a water availability certificate to confirm that there is adequate domestic water flow, fire flow, and water pressure to accommodate (or supply) a new development. The water availability certificate is a basic report that SPU prepares for parcel owners requiring water service (for a new construction or renovating an existing facility to use for a new purpose). The water availability certificate may show fire flow information for a nearby tested or modeled hydrant, if there is one, but doesn’t determine whether the fire flow is adequate. Fire flow requirements are determined by your local fire department.

A water availability certificate is required for most development projects in Seattle or SPU-direct water service areas. Information about on-site or privately owned water mains or hydrants isn’t included. A water availability certificate may be issued during the master use permit or during the building permit process.

What is the purpose of a water availability certificate?

Washington state building code RCW 19.27.097 requires that building permit applicants provide proof of adequate water supply for the intended use of the parcel. For Seattle, the document used to provide adequate proof is the water availability certificate. In addition, SPU wants to ensure that:

  • Property owners are notified early in the permitting process that their project may require system improvements, such as a water main extension, hydrants, or additional water main line valves.
  • An adequate water supply to service each new development project exists.
  • New development projects will utilize their water service in a manner consistent with approved water usage regulations.
  • A new water service meets current SPU regulations.

Does my project require a water availability certificate?

Property owners who are constructing a new building or renovating an existing building to use for a new purpose typically need a water availability certificate. The following project types require a water availability certificate:

  • Any project requiring a change in water service.
  • Any project requiring a building permit for new construction or additions greater than 2,500 square feet of habitable space.
  • Any project requiring a master use permit for the division or re-division of land (i.e. subdivision, short plat, unit lot subdivision, or lot boundary adjustment).

Not all projects require a water availability certificate. SPU and the Seattle Department of Construction & Inspections (SDCI) will determine whether a water availability certificate is required based upon project parameters. In some cases, such as replacing one single family residence with another single family residence, SDCI will issue a water availability approval without requiring a water availability certificate from SPU.

How do I apply for a water availability certificate?

1. Apply for a water availability certificate

There are 2 ways to apply for a water availability certificate.

  1. If you are applying for a building or master use permit from SDCI, a water availability certificate request is automatically generated through SDCI’s permit process.
  2. Apply for a water availability certificate (pdf) directly from SPU if:
      Your request is prior to applying for a SDCI building or master use permit,
      You are looking at a property to develop and you would like information on what water improvements may be required, or
      Your property is in an SPU direct water service area.

Make sure the request form is complete, accurate and legible.

2. Provide an adequate site plan

The site plan requirements align with the SDCI’s basic site plan requirements (pdf), which is the same site plan required for their preliminary application report. If you are applying for a water availability certificate (pdf) directly from SPU, email the site plan and application as separate PDF attachments.

3. Water availability certificate issuance

Water availability certificates are typically issued via email within 5 business days, depending on the volume of requests. There is no charge for this service.

How to reduce delays

  • Check with your local fire department to ensure the water service requested is sufficient to meet all fire department standards for the property.
    • For example, fire sprinkler systems require a separate or larger water service.
  • Contact the Development Services Office if a hydrant flow test is required by your local fire department.
  • Changes to a project after a water availability certificate is issued, particularly changes in parcel configuration, or water needs (such as fire sprinklers or landscape irrigation), require a new water availability review. This may result in delays or additional costs to your project.
  • Water availability certificates expire 18 months from the date of issue. Make sure your water availability certificate is valid when applying for a water service.

How are water services regulated?

Seattle Municipal Code (SMC) outlines water rates and regulations in SMC Chapter 21.04. The State of Washington defines basic regulatory requirements to protect the health of consumers using public drinking water in WAC Chapter 246-290.


For more information on water availability certificates, contact

For general questions, contact or call (206) 684-3333.

Useful links

Legal disclaimer

This Client Assistance Memo (CAM) should not be used as a substitute for codes and regulations. The applicant is responsible for compliance with all code and rule requirements, whether or not described in this CAM.