Why do we have a Stormwater Code?
 

Rain water running off of our urban land surfaces can cause flooding, landslides, erosion, and other hazards. It can also carry pollutants into our creeks, lakes, bays and other receiving waters. Stormwater regulations are needed to protect people, property, and the environment from damage that can be caused by stormwater runoff. Seattle’s stormwater regulations are also written to satisfy the City’s obligation to enact regulations to comply with your Municipal Stormwater Discharge National Pollutant Discharge Elimination System (NPDES) Permit, issued to the City by the Washington State Department of Ecology (Ecology). The regulations are also consistent with the State’s Growth Management Act (GMA) requirement that regulations affecting critical areas protect the functions and values of critical areas, in balance with other GMA goals and requirements.

What is in our Stormwater Code?
 

Seattle’s stormwater code includes:

1. A chapter describing the purpose, scope, applicability, exemptions, adjustments, exceptions, authorities, and compliance requirements;
2. Definitions of key terms;
3. Prohibitions of certain discharges and conditions for permissible discharges;
4. Minimum requirements for all discharges and all real property designed to reduce the introduction of pollutants into stormwater runoff as close to the source as possible;
5. Minimum requirements for all projects regarding stormwater pollution prevention during construction and grading activities;
6. Minimum requirements for all projects regarding flow control and stormwater treatment facilities;
7. Drainage control review and application requirements; and
8.  Procedures for enforcing the Stormwater Code.

How are the regulations organized?

Seattle’s regulations consist of the Stormwater Code (SMC 22.800 - 22.808), the Grading Code (SMC 22.170), and four joint DPD/SPU Director's' Rules collectively referred to as the Stormwater Manual. The Director's’ Rules provide specifications, guidelines, and additional information necessary to meet the requirements of the Stormwater Code and Grading Code. The four Directors’ Rules are:

Volume 1:   Source Control Technical Requirements Manual;

Volume 2:   Construction Stormwater Control Technical Requirements Manual;

Volume 3:   Stormwater Flow Control and Water Quality Treatment Technical Requirements Manual; and

Volume 4:   Stormwater Code Enforcement Manual.