Stormwater & runoff

We're working to reduce polluted runoff from streets, forests, and farms. When it rains, water flows across the land, streets, and sidewalks. Pollutants are carried by this water into local streams, lakes, and waterways. This is called runoff, or nonpoint pollution, and it is a problem for protecting water quality.

Runoff, or nonpoint pollution, can:

  • Carry toxic chemicals, nutrients, and bacteria into lakes, rivers, and marine waters.
  • Contribute to shellfish-harvest closures, harm salmon habitat, contaminate drinking water, and contribute to toxic chemicals in the food chain.

Washington's plan for preventing nonpoint pollution

We use a combination of technical and financial assistance, backed by state and federal laws, to ensure water quality is protected in Washington.

In 2022, we submitted an updated Water Quality Management Plan to Control Nonpoint Sources of Pollution or “Nonpoint Plan” to EPA for approval. This is a federally-required plan that outlines Washington’s approach to addressing water quality impacts from nonpoint sources, including agriculture, onsite septic systems, suburban and urban runoff, and forestry.

As part of our process, we solicited public comment and held an informational webinar to answer questions on the updates, as well as specific chapters of the Voluntary Clean Water Guidance for Agriculture. As part of the update process, we are working with stakeholders involved in nonpoint-pollution prevention. You can read the comments we received and our response to comments. Read our letter of submittal.

Land use practices affect water quality

The way you manage your land can have big impacts on water quality. We provide tools and guidance to keep sediment, bacteria, and nutrients from getting into state waters.

What types of runoff are we concerned about?

Agricultural runoff

Agricultural runoff can pollute streams and rivers. We provide guidance to landowners for keeping waters clean.

Forestry runoff

Degrading forest roads and logging practices create forestry runoff. State rules and initiatives that govern forest practices are designed to ensure that timber harvest and forest road activities don't pollute streams and rivers. We inspect and provide data to make sure these rules are followed and water quality is protected. 

Stormwater runoff

We issue various water quality permits that aim to control urban and stormwater runoff from industries, construction sites, cities, counties, ports, state highways, and boatyards.

Get involved in improving water quality

Protecting and improving water quality requires all of us to do our part. It can be as simple as picking up pet waste and throwing it in the trash or restoring trees and shrubs near streams on your property.