Stormwater Management

Mission Statement

Provide our customers with reliable and quality service at an affordable rate while protecting public health, natural resources, and receiving waters while and producing high-quality effluent that meets or exceeds local, state, and federal standards.

The Storm Drainage System—The Source of Storm Water and its Destination

Stormwater is water from rainfall that flows over the land into the City’s drainage system.  The drainage system includes:

• 1,580 catch basins
• 164 manholes
• 83 outfalls
• Over 29 miles of conveyance lines
• Over 8 miles of open ditches

In addition to this constructed stormwater system, Normandy Park includes parts of four creek basins and over 4 miles of stream channel in:

• Miller Creek
• Walker Creek
• Normandy Creek
• Des Moines Creek (drainage area only; no stream channel is in the city)

Stormwater runoff and groundwater affect water quality, water quantity, and habitat in these streams.  This in turn affects fish, birds, and wildlife.  There also is stormwater that flows directly into Puget Sound from areas of the city close to the marine shoreline.

Regardless of how it gets there, stormwater from Normandy Park influences the overall health of Puget Sound.

National Pollutant Discharge Elimination System (NPDES) Permit

Urban areas, including Normandy Park, that collect stormwater runoff in municipal storm sewers and discharge it to surface waters are required to prepare and submit a permit under the Federal Clean Water Act.

The NPDES permit mandates Normandy Park to create and implement a Stormwater Management Program (SWMP) and submit an annual report. Normandy Park’s SWMP goal is to protect water quality by reducing the discharge of pollutants from the City’s Municipal Separate Storm Sewer System (MS4) to the maximum extent practicable.

Are you interested in participating in the decision making process?  The city invites feedback on the development of the Stormwater Management Action Planning (SMAP) and the Stormwater Management Manual (SWMP).  Contact jmedrow@normandyparkwa.gov with questions or feedback.

The Components of the SWMP

1. Stormwater Planning

2. Public Education and Outreach

3. Public Involvement and Participation

4. MS4 Mapping and Documentation

5. Illicit Discharge Detection and Elimination

6. Controlling Runoff from New Development, Redevelopment and Construction

7. Stormwater Management for Existing Development

8. Source Control Program for Existing Development

9. Operations and Maintenance

2024 Annual Report

2025 Stormwater Management Program (SWMP) Plan

2023 Annual Report

2024 Stormwater Management Program (SWMP) Plan

2022 Annual Report

2023 Stormwater Management Program (SWMP) Plan

Stormwater Management Program Archives

An ongoing mapping program for mapping and documenting the Municipal Separate Storm Sewer (MS4) allows staff to maintain data for stormwater features.  This map will also help with ongoing efforts to prevent, detect, characterize, trace, and eliminate illicit connections and illicit discharges into the MS4.

Private Stormwater Facility Inspections and Maintenance

The Department of Public Works monitors storm drainage facilities within privately maintained developments. It is important that your drainage systems are operated and maintained according to standards established in Normandy Park Municipal Code (NPMC) Chapter 13.08.120, and other county, state, and federal regulations. The property owners shall remain responsible for the facility’s continual performance, operation and maintenance in accordance with these standards and requirements.

Thank you for protecting our lakes, rivers, and streams by maintaining your drainage system.

Click here for King County’s list of Drainage Maintenance Contractors

Common Stormwater Facilities in Normandy Park – Click here to review maintenance standards for your private stormwater facility.

• Manufactured Media Filter Vaults
• Type II Catch Basins
• Control Structure/Flow Restrictor
• Detention Systems

We Need Your Help

Everything that enters our constructed or natural drainage system finds its way into Puget Sound. Please do your part to preserve water quality and protect the environment today and for future generations:

• Employ Natural Yard Care
  • Use compost and mulch to build healthy soils.
  • Think twice before using pesticides to protect children and the environment.
  • Plant native trees and shrubs for their beauty and economy.
  • Water smart to save money, conserve water, and reduce runoff.
• Never pour oil, antifreeze, or paint on the ground or into a storm drain.
• Dispose of household hazardous waste properly.
• Keep soapy water out of storm drains by going to a commercial car wash or rinsing off the suds in a grassy area.
• Rent a Car Wash Kit: A FREE Car Wash Kit is available at City Hall. The SudSafe Car Wash Kit captures wastewater before it enters the storm drain and pumps it to either a grassy area or sewer. Detailed instructions are included in the kit.  Enjoy a clean car while knowing you are helping keep our creeks, streams, and waterways clean. (A $50 refundable deposit is required)
• Direct rainwater appropriately so it can percolate into the soil. (This may not be appropriate for homes at the tops of bluffs or steep slopes.)
• Become a better steward today – see Tips on How You Can Help Miller/Walker Creeks.

Thanks for doing your part to help keep the city of Normandy Park and Puget Sound clean, healthy, and beautiful!