Seattle Public Utilities

Green Strategies

Green strategies include the complete suite of actions that minimize impacts to the environment.

Green stormwater strategies include flow control and treatment facilities that use infiltration, evapotranspiration, or stormwater reuse.

Examples of green infrastructure technologies include permeable pavement, bioretention facilities, and green roofs.

Broader green strategies include building design, construction techniques, land use limitations, and other actions that result in minimizing environmental impact.

Combined Sewer Overflow

After decades of urbanization, the quality of our lakes, rivers and Puget Sound is threatened by urban runoff and the limitations of a 100-year-old drainage system. During heavy rains, the combination of stormwater (about 90 percent of the volume) and sewage may exceed the capacity of the drainage system and overflow into our waterways – causing a combined sewer overflow.

Learn more about Combined Sewer Overflow.

Natural Drainage Systems

Natural drainage systems (NDS) are an innovative alternative to traditional stormwater management systems. The pipes and ditches of traditional drainage systems carry runoff with traces of everyday contaminants such as oil, paint, fertilizer, and heavy metals directly into creeks, lakes, and Puget Sound. The speed and volume of water coming out of pipes erodes stream channels. These problems decrease water quality, disrupt marine food chains, and negatively impact wildlife habitat.

Learn more about Natural Drainage Systems.

City Green Building Team

Whether you’re working on a simple home remodel, a new apartment building or office tower, or a neighborhood pocket park, our staff of experts is here to help you successfully incorporate green building techniques.

Learn more about Green Building.

Thornton Creek Water Quality Channel

The Thornton Creek Water Quality Channel project will use natural drainage system technology – drainage that mimics the way nature works - to clean the water, slow it down and let water flow through the channel year-round.


You can help reduce stream erosion, pollution and sewer backups caused by excess stormwater runoff.

Learn more about the RainWise Program.