Surface Water Management

This division continuously works toward maintaining and improving the quality of our natural waterways as well as addressing flooding concerns. When rain flows across impervious surfaces such as rooftops, pavement and sidewalks, it picks up sediment and pollutants before it flows into our stormwater conveyance system and into our natural waterways. Stormwater can cause flooding, impact water quality and affect our streets. The Surface Water Management division manages stormwater runoff to prevent damage to people and property as well as to maintain and enhance our natural environment.

Efforts of the division include: surface water development review and inspections, maintaining public stormwater systems, inspecting privately maintained stormwater systems, monitoring our natural waterways, and providing stormwater education and outreach programs.

Newcastle has over 3,000 catch basins, 3,500 pipe sections, and over 80 stormwater facilities (detention ponds, tanks, and vaults). Our natural waterways include Lake Boren, China Creek, Boren Creek, May Creek, Newport Hills Creek, Gypsy Creek, and wetlands. To help protect our natural waterways and their ecosystems, it is essential that our stormwater systems are maintained regularly.
Newcastle’s Surface Water Management Program addresses both water quality (pollutants) and water quantity (flood control) problems.

Management of stormwater prevents physical damage to property from flooding and maintains the ecological integrity, quality and quantity of our local water resources.

Our Natural Waterways and Drainage Basins     
Newcastle lies within portions of three larger watersheds, Coal Creek watershed, East Lake 
Washington watershed, and May Creek watershed. Within each watershed, there are smaller drainage basins. More information about our drainage basins is available in section 3.2 of our Comprehensive Surface Water Management Plan. Natural waterways within Newcastle include Lake Boren, China Creek, Boren Creek, Newport Hills Creek, Gypsy Creek, May Creek, and wetlands.

Capital Improvement Projects

The City repairs, retrofits, and adds new stormwater facilities where needed for water quality and water quantity control. The City also restores and enhances our streams and wetlands. Our new Comprehensive Surface Water Management Plan will be completed in May 2017 and will prioritize future storm or surface water Capital Improvement Projects.

Comprehensive Surface Water Management Plan
This is a 5-year stormwater master plan that sets priorities for stormwater capital improvement projects. The plan makes recommendations based on the health of our natural waterways, maintenance requirements, and hydrologic and hydraulic models of our stormwater system.

2017 Comprehensive Surface Water Management Plan Update (Updated 2018)


If you need to report a hazardous spill or urgent matter 24 hours a day, 7 days a week, call 206-296-3311.

To report a non-hazardous spill during regular business hours
(Monday-Friday, 8 a.m. to 5 p.m.)
Call 425-649-4444

On evenings and weekends call 206-296-3311

For drainage concerns or other water quality concerns, submit a request using SeeClickFix at

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