Municipal Stormwater Monitoring

Regional Stormwater Monitoring Program

The Regional Stormwater Monitoring Program (RSMP) is a new collaborative monitoring program with western Washington municipal stormwater permittees and state agencies. The RSMP is based on recommendations from an independent stakeholder committee that outlined an overall strategy for a Stormwater Assessment and Monitoring Program for Puget Sound (SWAMPPS) with detailed technical appendices, and specific Recommendations for Municipal Stormwater Permit Monitoring.

Runoff and Outfall Monitoring

2013-2018 Permit

Phase I municipal permittees who opt out of RSMP effectiveness monitoring (Tacoma) or who cannot participate in the RSMP (Clark County) are required to collect and analyze stormwater discharge quality and quantity data. These Permittees are continuing monitoring at stormwater discharge locations monitored under S8.D of the 2007 permit; Tacoma is adding new locations. These permittees developed Quality Assurance Project Plans (QAPPs), which have been reviewed and approved by Ecology. The QAPPs contain detailed information about each Permittee’s monitoring program.

2007-2012 Permit

Phase I permittees were required to collect and analyze stormwater quality and quantity data, develop a QAPP, and develop and submit a Stormwater Monitoring Report as an attachment to the Annual Report. The monitoring described in Special Condition S8 of the Phase I Permit (2007-2012) included three monitoring components:

Southwest Washington Phase II Monitoring

Through the 2012 and 2013 Municipal Stormwater Grants of Regional or Statewide Significance program, Ecology provided the City of Longview with a grant to develop a regional status and trends monitoring design for southwest stormwater permittees. The City partnered with the Lower Columbia Fish Recovery Board (LCFRB) and the Pacific Northwest Aquatic Monitoring Partnership (PNAMP) to implement the project.

The project was intended to inform future Municipal Stormwater NPDES Permits in Southwest Washington by producing a monitoring design that addresses multi-scale questions about status and trends of physical, chemical and biological attributes impacted by stormwater. The project built on the progress of the Integrated Status and Trends Monitoring (ISTM) Project, which looks at ways to design and implement more coordinated, efficient, and effective aquatic ecosystem monitoring. In 2014, the Integrated Habitat Status and Trends Monitoring project entered the second stage.

Objectives include:

  1. Finalize the monitoring design for the entire Lower Columbia River Region including the Oregon portion.
  2. Create a pilot study design and implementation plan to test the monitoring strategy.
  3. Implement an outreach program to get feedback and share ideas among stakeholders and interested parties.

Monitoring Design:
Final Technical Report 1
Final Technical Report 2
Final Technical Report 3

Stakeholders interested in participating in this effort should contact Ecology Staff listed below:

Ecology Contact:
Karen Dinicola - - 360-407-6550

Washington State Department of Transportation

The Washington State Department of Transportation (WSDOT) (NPDES) Municipal Stormwater Permit requires WSDOT to collect and analyze stormwater quality and quantity data. The monitoring described in Special Condition S7 of the WSDOT Permit include four monitoring components:

  1. Baseline Monitoring of WSDOT Highways (S7.B)
  2. Monitoring the Effectiveness of Stormwater BMPs at Rest Areas, Maintenance Facilities, or Ferry Terminals (S7.C)
  3. Monitoring the Effectiveness of Stormwater BMPs at Highways (S7.D)
  4. Puget Sound Status and Trend Monitoring (S7.E)

Specific requirements for monitoring can be found in Special Condition S7 of the WSDOT Permit.

Monitoring Resources from Permittees

The City of Seattle developed software to help verify and validate analytical chemistry data. This Electronic Data Deliverable (EDD) Processing Tool was developed to support Phase I stormwater monitoring programs conducted under S8.D of the Phase I Municipal Stormwater Permit. You can review the User’s Guide for additional information. To obtain the software, contact your Ecology regional permit specialist. Please note that due to licensing limitations this tool is only available to NPDES permit holders in Washington State. Funded by an Ecology Stormwater Grant of Regional or Statewide Significance.


Monitoring Programs

Standard Operating Procedures

See the Environmental Assessment Program's (EAP) Quality Assurance page for standard operating procedures for automated, grab, and sediment trap sampling, among others. For further guidance see Phase I Monitoring Report Guidance (2012-2013).