For decades, communities have been legally required to stop stormwater pollution from entering Puget Sound.

As of 2020, there was no comprehensive resource or database publicly reporting how many, what, and where stormwater retrofits have been implemented by our municipalities. This valuable information is foundational to understand progress made toward stormwater control, and how much further we must go to protect our communities from stormwater pollution.

Stormwater Regulations

The Clean Water Act is the primary environmental law that protects our communities and waterways against all types of water pollution, including stormwater pollution from various sources.

The Washington Department of Ecology (Ecology) implements and enforces the Clean Water Act in the Puget Sound region. Ecology issues Clean Water Act stormwater Permits to municipalities throughout Puget Sound and works with Permittees to ensure compliance.  

Ecology developed two General Permits for Western Washington municipalities: a Phase I and a Phase II Permit. Phase I included the first Permittees in 1995. They had the largest population sizes and densities at that time, and included King County, Seattle, Tacoma, Pierce County, Snohomish County, and Clark County.

The Phase II Permit came later, in 2007. The Phase II permit covers all other municipal jurisdictions that Ecology determines must regulate their stormwater discharges. 

Stormwater Requirements

All permittees must implement a Stormwater Management Program and take certain steps to protect their communities from stormwater pollution. Permittees must map their stormwater infrastructure, report known pollution issues to Ecology and fix those problems, engage in stormwater planning projects, perform education and outreach to communities about stormwater, and inspect businesses to stop illicit discharges to the storm sewer system.

Special protections are required for polluted water bodies that have a pollution plan in place. Permittees are also required to use green infrastructure to treat and control stormwater pollution.

Tracking Structural Stormwater Controls

Our Nature’s Scorecard 2022: Local Stormwater Pollution Controls Report documents the Structural Stormwater Control (SSC) projects that Phase I Permittees reported to the Department of Ecology from 2007–2021.

It also documents SSCs that certain Phase II Permittees implemented during the same period, despite not having any regulatory requirements to do so. 

We assessed several additional criteria for all projects: whether they were located within the built environment or in undeveloped areas; whether they were located within areas where salmon were most likely to be killed by stormwater pollution; and whether they were located in areas where communities experience the worst environmental health outcomes. Permittees could do a better job of addressing stormwater impacts by investing in retrofits in these types of areas.

See our findings and learn about stormwater investments in your community.