Clean Water Act: Section 401 Water Quality Certifications

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2023 EPA Water Quality Certification Rule

September 27, 2023 - The U.S. Environmental Protection Agency (EPA) has finalized a new rule revising and replacing the 2020 regulatory requirements for water quality certification under Section 401 of the Clean Water Act. The rule is effective Nov. 27, 2023. 

Passed by Congress in 1972, the federal Clean Water Act grants states and Tribal governments the authority to review and approve, condition, or deny proposed projects, actions, and activities directly affecting waters of the United States. In Washington, Ecology is the certifying authority and is responsible for issuance of Section 401 water quality certifications. Tribal governments and the EPA also have this authority on Tribal and nonstate lands.

Under Section 401 of the Clean Water Act, federal agencies can't issue a license or permit before we make a determination on a water quality certification request or waive our right to review. Any conditions that the certifying agency sets then become conditions of the federal permit or license.

Requesting a Section 401 water quality certification

To request a water quality certification:

  • 30 days prior to requesting a water quality certification, applicants must submit a pre-filing request form.
  • At least 30 days after submitting a pre-filing meeting request, applicants may then submit their entire Section 401 request, along with a 401 Request Form, to Ecology.
    • For all projects requiring a federal permit, a copy of the federal permit application must be submitted with your water quality certification request. 
    • For most requests, the federal permitting agency is typically the U.S. Army Corps of Engineers. For hydropower dams, the federal permitting agency is the Federal Energy Regulatory Commission. For National Pollutant Discharge Elimination System (NPDES) permits, the federal permitting agency is the EPA.

Applicants must submit their pre-filing meeting requests, water quality certification requests, and any supporting documents to us electronically at

If you are having any difficulties accessing or using these forms, please contact our Federal Permits Unit at or 360-407-6076.

Examples of projects requiring 401 water quality certification

Section 401 water quality certifications allows us to review and condition projects, actions, and activities that can affect water quality in Washington. For example:

  • When a port seeks permission to dredge a channel or waterway, we outline where dredge spoils can go.
  • When hydropower projects request a license for an existing dam or for new construction, we assess whether state water quality standards are met and set conditions to make sure state waters are protected.
  • We review projects with proposed wetland impacts to protect them during site development and to determine when mitigation is necessary.
  • When shoreline property owners propose new piers and other structures, we work with them to protect water quality and minimize environmental impacts.

When we issue a Section 401 water quality certification, it means we have determined that a project or action, as proposed or as conditioned, will comply with state water quality requirements and protect aquatic resources.

Certification for specific federal permits and licenses

FERC hydropower licenses

We work with the Federal Energy Regulatory Commission (FERC) to re-license existing dams or license new construction for hydropower dams. When an applicant requests a certification for a hydropower license, we work with the utility or project proponent and review the applicable studies, analyses, and plans. If we determine that water quality standards are attainable, a Section 401 water quality certification is issued with appropriate conditions to make sure environmental standards will be met. These conditions become part of the new FERC license.

U.S. Army Corps of Engineers permits

All projects affecting navigable and protected waters in Washington state, as defined by the federal government, are subject to Section 401 water quality certification. These waters include coastal and marine environments, rivers, streams, lakes, and wetlands. This provides a strong opportunity to protect and enhance water quality, aquatic species and habitats, water resources, coastal resources, floodplains, and other environmental elements. This process excludes hydropower and NPDES-related projects.

EPA and Tribal permits

EPA and Tribal governments use National Pollutant Discharge Elimination System (NPDES) permits to ensure water quality and to limit the quantity of wastewater and stormwater discharge into surface waters like rivers, lakes, and streams. We write NPDES permits for all non-federal discharges in the state, except those on federal and Tribal lands.

Nonfederally regulated waters

Washington state defines state waters separate from the federal government. Projects affecting state waters that don't fall under the federal jurisdiction of "waters of the United States" are not subject to federal 401 water quality certification. However, they are still subject to applicable state water quality and environmental protection laws. This may include ponds, wetlands, and ephemeral streams, etc. that don't meet the definition of "waters of the United States."

Recent Section 401 decisions and public notices

All public notices for Section 401 water quality certification and our recent decisions are listed in our reporting databases. Information for notable Section 401 submissions and decisions also are detailed below.

Notable 401 decisions and requests