CITY OF RENTON WASHINGTON

Public Education and Outreach

Public Involvement and Participation

Recommended Activities

2024-2029 Phase II Permit Requirements

MS4 Mapping and Documentation

Illicit Discharge Detection and Elimination

Controlling Runoff from New Development, Redevelopment, and Construction Sites

Stormwater Management for Existing Development

Operations and Maintenance

Source Control Program for Existing Development

Total Maximum Daily Load Requirements

2024-2029 Phase II Permit Requirements

Monitoring

2024-2029 Phase II Permit Requirements

Reporting

Introduction and Background

APPENDICES

Appendix A Coordination Mechanisms

External Coordination Mechanisms

Internal Coordination Mechanisms

ACKNOWLEDGEMENTS

Funding for the SWMP Plan was provided by a Municipal Stormwater Capacity Grant from the Washington State Department of Ecology. Major content of this Plan was provided by Herrera.

INTRODUCTION AND BACKGROUND

In 1987, Congress amended the federal Clean Water Act to address municipal stormwater discharges through the National Pollution Discharge Elimination System (NPDES) permits. In Washington State, the Washington State Department of Ecology (Ecology) is responsible for issuing and renewing these permits. In 2007, NPDES Municipal Stormwater permits were issued in Washington for two groups of permittees: Phase I jurisdictions and Phase II jurisdictions.

Phase I permits were issued to large municipalities and county governments with populations over 100,000 (as of the 1990 census). Phase II Permits were issued to smaller governmental entities generally with populations between 10,000 and 100,000. The City of Renton (city) is covered under Western Washington’s Phase II Municipal Separate Stormwater Sewer System (MS4) NPDES permit (Phase II Permit).

Discharges from MS4s (systems designed to collect and convey stormwater runoff) are regulated by Ecology under the NPDES program. The municipal NPDES permit seeks to control or reduce pollutant discharge to the maximum extent practicable, primarily through programmatic efforts. The city is regulated by Ecology as a Phase II permittee. The first Phase II Permit became effective on February 16, 2007, was modified in 2009, and expired on February 15, 2012. Ecology extended the 2007–2012 Phase II Permit requirements until July 2013. The second Phase II Permit was issued on August 1, 2012 and became effective on August 1, 2013. Ecology extended the 2013-2018 Phase II Permit requirements until July 2019. The third Phase II Permit was issued on July 1, 2019 and became effective on August 1, 2019. The fourth Phase II Permit was issued on July 1, 2024 and becomes effective on August 1, 2024. For fiscal year 2024 (July 1, 2023 through June 30, 2024), the city was charged an annual permit fee of $72,665 by Ecology. This annual fee will likely increase with future Phase II Permit updates.

The Phase II Permit requires the city to develop a Stormwater Management Program (SWMP). The SWMP must include the following components:

A stormwater planning program to inform and assist in the development of policies and strategies as water quality management tools to protect receiving waters.
An education and outreach program designed to build general awareness about methods to address stormwater impacts, affect behavior change to reduce behaviors that lead to adverse stormwater impacts, and create stewardship opportunities that encourage the community to address stormwater impacts.
A public involvement and participation program to provide opportunities for the public to get involved in the development, implementation, and update of the SWMP and SMAP.
An ongoing program to map and document the MS4.
An ongoing illicit discharge detection and elimination (IDDE) program to prevent, detect, characterize, trace, and eliminate illicit connections and illicit discharges into the MS4.
A program to reduce pollutants in stormwater runoff to the MS4 from new development, redevelopment, and construction site activities
A program to control or reduce pollutants in stormwater runoff from areas of existing development
A program to prevent and reduce pollutant runoff from areas that discharge to the MS4
An operation and maintenance (O&M) program to regulate and conduct maintenance activities to prevent or reduce pollutant runoff

In addition, the Phase II Permit requires that the city prepare written documentation of the SWMP and update that documentation annually. This SWMP plan satisfies this requirement. In addition to the nine components listed above, this SWMP plan includes a discussion of the total maximum daily load, monitoring, and reporting requirements of the Phase II Permit.

This SWMP plan also includes a description of the city’s external and internal coordination mechanisms as required by permit sections S5.A.5.a and S5.A.5.b, respectively in Appendix A.

COMPREHENSIVE STORMWATER

PLANNING

The city plans to implement the comprehensive stormwater planning requirements over the permit term, fulfilling the requirements of the permit by developing policies and strategies that protect receiving waters. The definition of receiving waters includes natural and constructed creeks, streams, rivers, lakes, wetlands, and groundwater to which Renton’s stormwater flows. This section describes the Phase II Permit requirements related to comprehensive stormwater planning, including planned activities.

2024–2029 Phase II Permit Requirements

Section S5.C.1 of the 2024–2029 Phase II Permit requires the city to implement a stormwater planning program to develop policies and strategies as water quality management tools to protect receiving waters. The specific Phase II Permit requirements are as follows:

Convene an interdisciplinary team to inform in the development, progress, and influence of the program.
Report on how stormwater management needs and receiving water protection/improvement inform the long-range planning update process and influence policies and implementation strategies. By March 31, 2027, describe the water quality and watershed protection policies, strategies, codes, and other measures to protect and improve receiving water heath through planning.
Annually assess and report newly identified administrative or regulatory barriers to implementation of low impact development (LID) principles or low impact development best management practices (LID BMPs) since local codes were adopted in 2016, and measures to address the barriers. Describe mechanisms to encourage or require LID implementation.
Adopt and implement tree canopy goals and policies to support stormwater management by December 31, 2028, documenting considerations, reasoning, and rationale. Establish a long-term goal of canopy for stormwater management. On Renton owned or operated properties, consider maintaining or increasing canopy in overburdened communities and maintaining existing mature canopy.
Implement stormwater management action planning to support the implementation of the Stormwater Management for Existing Development Program:

By March 31, 2027, develop a Stormwater Management Action Plan (SMAP) for at least one high priority area or additional actions for an existing SMAP.

Planned Activities

Interdisciplinary Team: The stormwater planning interdisciplinary team meets annually in the first quarter of the year and as-needed to inform the stormwater planning program.

Low Impact Development (LID) Implementation: Community and Economic Development (CED) Department’s Long Range Planning and Planning Divisions, Surface Water Utility (SWU) Engineering and Transportation Planning Sections, and the Parks Planning & Natural Resources Division will annually assess and document barriers and adopted mechanisms to encourage or require implementation of LID Principles or LID BMPs.
Stormwater Management Action Plan: The Interdepartmental NPDES Stormwater Planning Team will conduct a future assessment evaluation outlined in the Stormwater Management Action Plan (SMAP) for Johns Creek.

PUBLIC EDUCATION AND

OUTREACH

The city’s public education and outreach program currently includes a wide range of educational brochures for a variety of audiences. The city has a drain marker volunteer program and participates in the Stormwater Outreach for Regional Municipalities (STORM) coalition. This section describes the Phase II Permit requirements related to Public Education and Outreach, including the city’s planned compliance activities.

2024–2029 Phase II Permit Requirements

Section S5.C.2 of the 2024–2029 Phase II Permit requires the city to implement an education and outreach program based on water quality information and priority audience characteristics. Education and outreach efforts shall be prioritized in the following areas:

Build general awareness that annually selects at least one priority audience and one subject area from A or B:

General public (including overburdened communities or school age children), or businesses (including home-based or mobile businesses)

Subject areas:

General impacts of stormwater on surface waters, including impacts from impervious surfaces
Low impact development (LID) principles and LID BMPs

Engineers, contractors, developers, property owners/managers, or land-use planners

Subject areas:

Technical standards for stormwater site and erosion control plans
LID principles and BMPs
Stormwater treatment and flow control BMPs/facilities
Source control BMPs for building materials to reduce pollution to stormwater, including but not limited to stormwater pollution for PCB-containing materials

Affect behavior change that selects at least one priority audience and one BMP from the following:

Residents, landscapers, property managers/owners, developers, school age children, college/university, trade students, or businesses (including home-based or mobile businesses)

BMPs:

Use and storage of pesticides, fertilizers, and/or other household chemicals
Use and storage of automotive chemicals, hazardous cleaning supplies, carwash soaps, and/or other hazardous materials
Prevention of illicit discharges
Yard care techniques protective of water quality
Carpet cleaning
Repair and maintenance BMPs for vehicles, equipment, and/or home buildings
Pet waste management and disposal
LID principles and LID BMPs
Stormwater facility maintenance, including LID facilities
Dumpster and trash compactor maintenance
Litter and debris prevention
Sediment and erosion control
(Audience specific) Source control BMPs
(Audience specific) Locally important, municipal stormwater-related subject area

Based on the recommendations of the 2024 behavior change evaluation, by July 1, 2025, use social marking methods to develop a campaign tailored to the community, including an evaluation plan, strategy, and schedule.
By September 1, 2025, begin to implement the developed strategy.
By March 31, 2029, evaluate and report on changes in understanding and adopted behaviors resulting from the implemented strategy and on planned or recommended changes to the program to improve efficacy.
Use the evaluation results to continue to direct effective methods and implementation of the ongoing behavior change program.

Provide, partner with, or promote stewardship opportunities to encourage residents or businesses to participate in activities or events such as storm drain marking, volunteer monitoring, riparian plantings and watershed habitat improvement.

Planned Activities

General Awareness

Awareness Campaign: The SWU Engineering Section will promote Puget Sound Starts Here campaign messaging to build general awareness of the general impact of stormwater on surface water, including impacts from impervious surfaces through electronic and printed media, prioritizing the general public including overburdened communities.
Expand the Neighborhood Program: The Surface Water Utility will promote stormwater BMPs at the city’s Neighborhood Program events prioritizing the general public.
Online Solid Waste Outreach: The Sustainability & Solid Waste Section will provide education on natural yard care, hazardous waste management, and waste prevention prioritizing the general public.
Natural Yard Care Funding: The Water Utility will fund the Saving Water Partnership (SWP) to conduct natural yard care classes.
Nature Vision Classroom Programs: The Water Utility Section will provide the funding to conduct watershed science classes at elementary schools through the SWP.
Environmental Science Center Programs: The Surface Water Utility and Parks & Recreation Department will partner with the Environmental Science Center to provide stormwater education and field study to youth, adults, and seniors.

Behavior Change

Behavior Change Campaign: The SWU Engineering Section will evaluate and report on changes in understanding and adoption of spill kit training and recommended changes to the spill kit campaign to improve efficacy. The results will be used to continue to direct effective methods and implementation of the behavior change program.
Partner with Local Hazardous Waste Management: The Sustainability & Solid Waste Section will participate as a partner with local jurisdictions to provide outreach for proper handling and storage of hazardous materials and opportunities for their disposal.
Recycling Events: The Sustainability & Solid Waste Section will coordinate collection events for some household wastes that are difficult to recycle curbside, including scrap metals, Styrofoam, cardboard, and tires.
In-House Battery Recycling: The Sustainability & Solid Waste Section will provide collection of batteries for recycling at city facilities.
Oil Recycling and Best Practices: The Sustainability & Solid Waste Section will support and partner with automotive businesses to increase access to motor oil and filter recycling and provide education on safe handling practices.

Stewardship

Volunteer Storm Drain Marker Program: The SWU Engineering Section will coordinate civilian volunteer efforts to mark storm drains.
WRIA 8 and WRIA 9: The SWU Engineering Section will continue its partnership with WRIA 8 Salmon Recovery Council and WRIA 9 Watershed Ecosystem Forum to promote stewardship opportunities and sponsor Salmon SEEson which promotes Cedar River Salmon Journey.
Community Stewardship and Events: The Parks Planning and Natural Resources Division will coordinate community events to plant trees in public parks.

Environmental Science Center Programs: The Surface Water Utility will partner with the Environmental Science Center to provide volunteer water quality monitoring, restoration events, and stormwater activities for the general public.

Recommended Activities

Implementation timelines for these activities are to be determined, and depend on available staff and funding, as well as COVID-19 Health Concerns.

Expand Education Materials: The City of Renton’s Surface Water Utility will expand education materials available through existing programs and streamline stormwater outreach messaging and public handouts. Stormwater education and outreach should be integrated into existing Public Works programs. Consistent stormwater outreach messaging should be developed between various city departments. Handouts should be combined based on target audiences and redundant information on handouts should be eliminated.
Car Wash Outreach: The Surface Water Utility will provide alternative options to groups holding charity car wash events.
Aquifer Protection Program: The Water Utility will provide education on water quality and conservation at public events and on proper chemical storage to businesses in aquifer protection zones.
Natural Yard Care Program: The Surface Water Utility will provide classes teaching yard care methods to eliminate use of pesticides, herbicides, and chemical fertilizers.
Promote Community Stewardship: The Surface Water Utility will encourage community involvement with rain gardens, stream teams, volunteer monitoring, riparian planting, or education activities.
New Public Education Materials: The City’s Surface Water Utility will develop an illicit discharge handout, and mailing handouts to single-family residences, and circulate these handouts. Relevant handouts will be distributed at pre-application meetings. This activity also can be used to meet S5.C.5.b – informing public employees, businesses, and the general public of hazards associated with illicit discharges and improper disposal of waste.
Street Tree Replacement: Parks Planning & Natural Resources will work to fill planting spots and replace trees and distribute tree care information.
Illicit Discharge Education and Outreach: An interdepartmental team will work to develop a handout for companies that respond to spills associated with automobile accidents.
Volunteer Riparian Tree Planting: Parks & Trails will coordinate volunteer events to plant trees in riparian areas.

PUBLIC INVOLVEMENT AND PARTICIPATION

Public input is important to the development and implementation of city plans. The city actively solicits public participation by making stormwater information available for review and providing opportunities for comment through its website. This section describes the Phase II Permit requirements related to public involvement, including planned compliance activities.

2024-2029 Phase II Permit Requirements

Section S5.C.3 of the 2024-2029 Phase II Permit require that the city create opportunities for the public to participate in the decision-making processes involving the development, implementation, and update of the SWMP and SMAP, and comply with applicable state and local public notice requirements. The two main components include:

Document specific public involvement and participation opportunities provided to overburdened communities and specifically, highly impacted communities. By December 31, 2026, document methods used to identify overburdened communities.
Posting the Annual Report and the SWMP Plan, on the city’s website no later than May 31 of each year.

Planned Activities

Revise SWMP Plan: The Surface Water Utility (SWU) Engineering Section will update the SWMP Plan with planned activities for 2024.
Prepare and post SWMP Plan and Annual Report: The SWU Engineering Section will prepare and post the SWMP Plan and Annual Report on the City’s website and other supplemental documentation as applicable by May 31, 2024.
Public involvement in the SWMP and SMAP: The SWU Engineering Section will solicit public feedback on the City’s website (www.rentonwa.gov/npdes) and social media channels.

MS4 MAPPING AND DOCUMENTATION

The city maintains a current electronic map of the Municipal Separate Storm Sewer System (MS4) in the City of Renton Map Viewer (CORMaps), which is available to the public at https://maps.rentonwa.gov/Html5viewer/Index.html?viewer=cormaps. This section describes the MS4 Mapping and Documentation Phase II Permit requirements, as well as the city’s planned compliance activities for the 2024-2029 Phase II Permit cycle.

2024–2029 Phase II Permit Requirements

Section S5.C.4 of the 2024–2029 Phase II Permit requires the city include an ongoing program for mapping and documenting the MS4. The specific Phase II Permit requirements are as follows:

Maintain mapping data for these features:
1. Known MS4 outfalls, including size and material, and known MS4 discharge points
2. Receiving waters, other than groundwater
3. Stormwater treatment and flow control BMPs/facilities owned or operated by the city
4. Geographic areas served by the MS4 that do not discharge stormwater to surface waters
5. Tributary conveyances and associated features to known outfalls and discharge points with a 24” diameter or equivalent cross-sectional area
6. Connections between the city’s MS4 and other municipalities or public entities
7. All connections to the MS4 authorized or allowed by the city after February 16, 2007
8. All known connections from the MS4 to a privately owned stormwater system
Record mapping data for these features:
1. By March 31, 2026, submit locations of all known MS4 outfalls according to a Permit-specified template and format, and report size and material of outfalls.
2. By December 31, 2026, map tree canopy to support stormwater management on Renton owned or operated properties.
3. By March 31, 2028, implement a method to map and assess acreage of MS4 tributary basins to outfalls with a 24” diameter or equivalent cross-sectional area that have stormwater treatment and flow control BMPs/facilities owned or operated by the city. By March 31, 2028, submit a map and table with MS4 tributary basins quantifying estimated acres managed or unmanaged by stormwater treatment and flow control BMPs/facilities owned or operated by the city.
4. By December 31, 2028, map overburdened communities in relation to stormwater treatment and flow control BMPs/facilities, outfalls, discharge points, and tree canopy on properties owned or operated by the city.
Record map electronically with fully described mapping standards.
Make maps available upon request to Ecology, federally recognized Tribes, municipalities, and other Permittees.

Planned Activities

Maintain Mapping Data: The Surface Water Utility (SWU) Engineering Section will maintain a map of existing required MS4 features.
Map Outfall Features: The SWU Engineering Section will continue to map size and material of known outfall features during the course of normal business operations.
Electronic Map: The SWU Engineering Section will maintain an electronic map with fully described mapping standards.
Map Access: The City of Renton has mapping data available to the public via the online COR Maps GIS maps, and additional information will be provided to public entities upon request.

ILLICIT DISCHARGE DETECTION AND ELIMINATION

An illicit discharge is defined as any discharge into the stormwater system that is not composed entirely of stormwater, or of non-stormwater discharges allowed as specified in the Phase II Permit. Illicit discharges may be from a variety of sources and activities including illegal dumping, sanitary sewer overflow, swimming pool cleaning, and incidental spills (such as oil, gas, paints, or solvents). An Illicit Discharge Detection and Elimination Program is designed to protect surface water and ground water from being contaminated by illicit discharges by tracking, monitoring, and removing hazardous discharges in the stormwater drainage system. This section describes the Illicit Discharge Detection and Elimination (IDDE) Phase II Permit requirements, as well as the city’s planned compliance activities.

2024–2029 Phase II Permit Requirements

Section S5.C.5 of the 2024–2029 Phase II Permit requires the city to include an ongoing IDDE Program designed to prohibit, prevent, detect, characterize, trace, and eliminate illicit connections and illicit discharges into the stormwater system. The specific Phase II Permit requirements are as follows:

Implement a program with procedures to report and address illicit discharges including spills, and illicit connections, and procedures to address pollutants from an interconnected, adjoining MS4.
Inform public employees, businesses, and the public of the hazards associated with illicit discharges and improper disposal of waste.
Implement an ordinance that effectively prohibits non-stormwater, illicit discharges into the MS4. Evaluate and update existing ordinances, as needed, by July 1, 2027.
Implement and document a field screening method for illicit discharges and connections, complete screening an average of 12 percent of the stormwater system per year.
Publicize a public hotline number for reporting of spills and other illicit discharges; and track all calls and follow-up actions taken.
Implement an ongoing training program for municipal field staff on identification and reporting procedures.
Implement an ongoing program designed to address illicit discharges, including spills and illicit connections, which includes procedures for characterizing the nature and potential threats of an illicit discharge, procedures for tracing the source of an illicit discharge, and procedures for eliminating the discharge within specific timeframes. Coordinate with firefighting agencies for notification of PFAS-containing AFFFs used during emergency firefighting by December 31, 2026 and update and implement procedures to minimize discharges to the MS4 during post-emergency clean-up and disposal activities by January 1, 2027.
Implement an ongoing training program for staff responsible for identification, investigation, termination, cleanup, and reporting.
Track and maintain records of IDDE activities following the Permit-specified format.

Planned Activities

Coordination with Adjoining MS4s: The Surface Water Utility (SWU) Engineering and Surface Water (SW) Maintenance Sections will coordinate with adjacent jurisdictions to address pollutants from adjoining MS4s.
Illicit Discharge Program Implementation: The Public Works, Community and Economic Development (CED), and Parks & Recreation Departments will implement the City’s IDDE training and NPDES Spill Response Standard Operating Procedures to report, and correct or remove illicit connections and illicit discharges in the City.
Business Education and Outreach: The SWU Engineering Section will inform businesses of illicit discharge hazards and improper disposal of waste during source control inspections.
Illicit Discharge Ordinance: SWU Engineering and SW Maintenance Sections, and Community and Economic Development (CED) Code Compliance will evaluate the effectiveness of the existing ordinance for prohibiting illicit discharges.
Illicit Discharge and Illicit Connection Field Screening: The SW Maintenance Section, and Airport, Facilities, Parks & Trails, and Golf Course Divisions will use field screening methodologies from the 2020 Illicit Discharge Field Screening and Source Tracing Guidance Manual to screen for illicit connections in 12% of the storm system on average each year.
Spill Hotline: The SWU Engineering Section will publicize the spill hotline to report spills and other illicit discharges.
Staff Training: The Interdepartmental Team will train field staff on IDDE reporting and SW Maintenance will train staff on investigation, tracing, termination, and cleanup. Training is conducted annually through in-person meetings or virtually and on an as-needed basis.
Record Keeping: The SWU Engineering and SW Maintenance Sections, and Airport, Facilities, Parks & Trails, and Golf Course Divisions will utilize Cityworks, Excel, or similar tracking software to record IDDE activities per Permit-specified format.

CONTROLLING RUNOFF FROM NEW DEVELOPMENT, REDEVELOPMENT, AND CONSTRUCTION SITES

New development can cause erosion and introduce sediment and polluted runoff into local waters. The City of Renton regulates and inspects construction sites to ensure best management practices are in use. The CED Development Services, Development Engineering, and Planning Divisions are responsible for permitting, inspection, and code enforcement actions for private construction-related activities in the city. City project managers are responsible for stormwater review of public capital projects. This section describes the Phase II Permit requirements related to controlling runoff from new development, redevelopment, and construction sites, including planned activities.

2024–2029 Phase II Permit Requirements

Section S5.C.6 of the 2024–2029 Phase II Permit requires that the city implement and enforce a program to reduce pollutants in stormwater runoff to the MS4 from new development, redevelopment, and construction activities. The specific Phase II Permit requirements are as follows:

Implement an ordinance that addresses runoff from new development, redevelopment, and construction sites and adopt minimum requirements, thresholds and definitions in Appendix 1 of the Phase II Permit or approved program and amendments by June 30, 2027.
Review all stormwater site plans for proposed development activities.
Conduct inspections of construction sites prior to clearing and construction, during construction, and upon completion of construction.
Conduct inspections of all stormwater treatment and flow control BMPs/facilities and catch basins in new residential developments at least twice per 12-month period with no less than 4 months between inspections until 90% of the lots are constructed.
Maintain records of inspections, maintenance activities, and enforcement activities.
Implement an enforcement strategy to respond to non-compliance issues.
Provide a link to state stormwater general permit NOI forms for construction and industrial sites and a link to the online registration requirements for Underground Injection Control (UIC) wells.
Conduct ongoing training for staff responsible for implementing the program to control stormwater runoff from new development, redevelopment, and construction sites.

Planned Activities

Implement and Adopt Program Amendments: The CED Department and SWU Engineering Section will implement the current ordinance to meet the minimum requirements, thresholds and definitions in Appendix 1 of the Phase II Permit or an approved program and amendments.
Stormwater Site Plan Review: The Community and Economic Development (CED) Development Engineering Section and Capital Improvement Program (CIP) Leads will review all stormwater site plans for proposed development activities in accordance with the City of Renton Surface Water Design Manual.
Preconstruction Inspections: The CED Planning Division will inspect construction sites prior to construction if they exhibit high sediment transport potential.
Construction Inspections: The CED Construction Inspectors and CED Building Inspectors will inspect all sites during construction to verify proper installation and maintenance of required erosion and sediment controls.
Residential Construction Inspections: The Surface Water Utility (SWU) Engineering Section will inspect stormwater facilities and catch basins in new residential developments every six months until 90% of lots are constructed, and will identify maintenance needs and enforce maintenance standards.
Post-Construction Inspections: The CED Construction Inspectors and CED Building Inspectors will inspect all sites after construction to ensure proper installation of permanent stormwater facilities, verify that maintenance plan is complete and maintenance responsibility is assigned.
Development Site Enforcement: The CED Construction Inspectors, Building Inspectors and Code Enforcement will implement enforcement strategy for sites that are not in compliance.
Notice of Intent Availability: The Development Engineering Section will provide links to the Construction and Industrial Permits’ NOI forms and UIC injection well registration requirements on the City’s website under “Other Resources”.
Recordkeeping: The CED Planning Division, Building Inspectors and the SWU Engineering Section will maintain records of inspection, maintenance, and enforcement actions.
Staff Training: The CED Planning and Development Services Divisions will train staff in permitting, plan review, construction site inspections, and enforcement and maintain training records. Training is conducted annually and on an as-needed basis (e.g. new hires, recertifications).

STORMWATER MANAGEMENT FOR EXISTING DEVELOPMENT

The City plans to control or reduce stormwater discharges to receiving waters from areas of existing development. The SWU Engineering Section is responsible for implementing stormwater investment projects. This section describes the Phase II Permit requirements related to stormwater management for existing development, including planned activities.

2024–2029 Phase II Permit Requirements

Section S5.C.7 of the 2024–2029 Phase II Permit requires the city to implement a program to control stormwater discharges from existing development. The specific Phase II Permit requirements are as follows:

Implement stormwater facility retrofits or tailored SWMP actions using strategic and/or opportunistic stormwater investments.
Implement Annually, provide a list of planned projects scheduled for funding or implementation for the purpose of meeting the permit-specified area to be managed by the city per Appendix 12 of the permit.
Fully fund, start construction, or completely implement projects that meet the permit-specified area to be managed by the city per Appendix 12 of the permit, and submit documentation by March 31, 2028.
Report on the amount of estimated or projected permit-specified area managed by stormwater facility retrofits for the next Permit term (2029-2032) by March 31, 2028.

Planned Activities

Implement Stormwater Facility Retrofits: The SWU Engineering Section will implement an opportunistic stormwater facility retrofit to control flows and improve water quality in the Cedar River basin.
List of Planned Projects: The SWU Engineering Section will annually provide a list of planned projects scheduled for funding or implementation for the purpose of meeting the permit-specified area to be managed by the city per Appendix 12 of the permit.

OPERATIONS AND MAINTENANCE

Maintenance of MS4 infrastructure is conducted to prevent or reduce stormwater impacts such as flooding and pollutant discharges into receiving waters. City staff from Public Works and Parks & Recreation are responsible for operations and maintenance of MS4 infrastructure. This section describes the Phase II Permit requirements related to operations and maintenance, including planned activities.

2024–2029 Phase II Permit Requirements

Section S5.C.9 of the 2024–2029 Phase II Permit requires the city to implement and document an O&M program to regulate and conduct maintenance activities to prevent or reduce stormwater impacts. The specific Phase II Permit requirements are as follows:

Implement maintenance standards that are at least as protective as those specified in Ecology’s Stormwater Management Manual for Western Washington or approved program. No later than June 30, 2027, update maintenance standards as needed.
Implement provisions to verify adequate long-term operation and maintenance (O&M) of stormwater treatment and flow control BMPs/facilities.
Conduct annual inspections of all stormwater treatment and flow control BMPs/facilities that discharge to the stormwater system and were permitted by the city since 2010 (unless maintenance records justify a reduced inspection frequency).
Perform annual inspections of all city-owned or operated permanent stormwater treatment and flow control BMPs/facilities, other than catch basins, and take appropriate maintenance actions (unless maintenance records justify a reduced inspection frequency).
Spot check potentially damaged permanent treatment and flow control BMPs/facilities (other than catch basins) after major storm events; and conduct maintenance and repairs as needed.
Perform routine catch basin and inlet inspections. Clean as needed based on maintenance standards. Elect to use an alternative approach to inspection if desired.
Implement and document practices, policies, and procedures to reduce stormwater impacts associated with runoff from all lands owned or maintained by the city and road maintenance activities under the functional control of the city. Update policies, practices, or procedures related to building and document them by December 31, 2027.
Develop and implement a municipal street sweeping program to sweep priority areas three times per year by July 1, 2027.
Implement Stormwater Pollution Prevention Plans (SWPPPs) for all heavy equipment maintenance or storage yards and material storage facilities owned or operated by the city. Update SWPPPs as needed.
Implement an ongoing training program for city staff whose primary construction, operations, or maintenance job functions may impact stormwater quality.
Maintain records of inspections, maintenance, repair, and enforcement activities.

Planned Activities

Implement Maintenance Standards: Surface Water (SW) Maintenance Section and Airport, Facilities, Parks & Trails, and Golf Course Divisions will implement maintenance standards and perform maintenance per the required schedule.
Private Stormwater Facility Inspections: The SWU Engineering Section will annually inspect private stormwater facilities constructed since February 2010, identify maintenance needs, and enforce maintenance standards.
Stormwater Treatment and Flow Control Facility/BMP Inspections: The SW Maintenance Section, and Airport, Facilities, Parks & Trails, and Golf Course Divisions will conduct spot check after major storm events and annually inspect city-owned or operated stormwater facilities, identify maintenance needs and maintain and repair facilities in accordance with maintenance standards.
Catch Basin Inspection Program: The Facilities and Airport Divisions will implement the standard approach of inspecting catch basins and inlets every two years and cleaning per maintenance standards. The Parks & Trails and Golf Course Divisions will conduct inspections on a “circuit basis" every two years (i.e. 25% of catch basins and inlets in a circuit are inspected, and if needed to comply with maintenance standards, all catch basins and inlets in the circuit are cleaned). The Surface Water Maintenance Section will clean all pipes, ditches, catch basins, and inlets once during the permit term.
Maintenance Practices, Policies, and Procedures: The SW Maintenance Section, and Airport, Facilities, Parks & Trails, and Golf Course Divisions will implement documented practices, policies, and procedures to reduce stormwater impacts associated with Permit-specified O&M activities. The SWU Engineering Section and Facilities Division will update practices, policies, and procedures related to buildings.
Stormwater Pollution Prevention Plan (SWPPP): The Public Works Maintenance Division will implement the SWPPP for the Maintenance Shops Facility.
Staff Training: The SW Maintenance Section, and Airport, Facilities, Parks & Trails, and Golf Course Divisions will pursue training opportunities for maintenance staff. Training is conducted on an as-needed basis (e.g. new hires, recertifications).
Record Keeping: The SWU Engineering and SW Maintenance Sections, and Airport, Facilities, Parks & Trails, and Golf Course Divisions will record O&M activities, including inspections, maintenance, and enforcement.

SOURCE CONTROL PROGRAM FOR EXISTING DEVELOPMENT

The City implements the source control program to prevent and reduce stormwater pollutants from areas that discharge to the MS4. The SWU Engineering and SW Maintenance Sections, and CED Code Compliance are responsible for inspection and enforcement of the source control program. This section describes the Phase II Permit requirements related to the source control program for existing development, including planned activities.

2024–2029 Phase II Permit Requirements

Section S5.C.8 of the 2024–2029 Phase II Permit requires the city to implement a program to prevent and reduce pollutants in runoff from areas that discharge to the MS4. The program includes applying operational and structural best management practices (BMPs), and treatment BMPs if needed, to existing sources, inspecting BMP implementation at commercial and industrial properties, and applying and enforcing local ordinances at sites. The specific Phase II Permit requirements are as follows:

Enforce an ordinance to require source control BMPs for pollutant generating sources associated with existing land uses and activities. Evaluate and update the existing ordinance, as needed, by August 1, 2027.
Establish, and update at least once every 5 years, an inventory of commercial, institutional, and industrial properties with pollutant generating potential.
Implement an inspection program, performed by qualified personnel, for sites identified in the inventory.

Provide sites with information about pollutant generating activities and applicable source control requirements.
Annually complete the number of inspections equal to 20% of the businesses and/or properties listed in the inventory, and inspect all sites identified through complaints.
Annually report inspections organized by business type or activities with pollutant generating potential.

Implement a progressive enforcement policy to include follow-up actions such as correspondence, additional inspections, and enforcement actions and document efforts to bring sites into compliance.
Conduct training for staff responsible for implementing the source control program.

Planned Activities

Educate Businesses: The SWU Engineering and SW Maintenance Sections, and Airport Division will inform businesses about activities that may generate pollutants and applicable source control requirements.
Inspect Businesses and/or Sites: The SWU Engineering and SW Maintenance Sections will annually inspect an equivalent number of 20% of businesses and/or sites in the inventory and all complaints.
Enforce Source Control Program: The SWU Engineering and SW Maintenance Sections, and Community and Economic Development (CED) Code Compliance will implement a progressive enforcement policy, documenting inspections and follow-up actions.
Staff Training: The SWU Engineering and SW Maintenance Sections, and CED Code Compliance will pursue training opportunities for source control program staff. Training is conducted on an as-needed basis (e.g. new hires, recertifications).

TOTAL MAXIMUM DAILY LOAD REQUIREMENTS

This section provides a brief discussion of the Phase II Permit total maximum daily load (TMDL) requirements.

2024-2029 Phase II Permit Requirements

Section S7 of the NPDES Phase II Permit lists the following requirements:

Implement the specific requirements identified in Appendix 2 of the Phase II Permit for applicable TMDLs listed in Appendix 2.
Compliance with the permit constitutes compliance with applicable TMDLs not listed in Appendix 2 of the Phase II Permit.

Planned Activities

The city is not required to implement actions for compliance with total maximum daily loads (TMDLs) pursuant to Section S7 and Appendix 2 of the Phase II Permit, since the city is currently not affected by any TMDLs listed in Appendix 2 of the NDPES Phase II Permit.

MONITORING

Monitoring and assessment are important to fully understand the impacts and effectiveness of stormwater management programs. This section provides a brief discussion of the Phase II Permit monitoring requirements including planned activities.

2024–2029 Phase II Permit Requirements

Section S8 of the 2024–2029 Phase II Permit requires the city to do the following:

For the previous permit cycle, pay into a collective fund to implement regional status and trends monitoring and effectiveness and source control identification studies by December 1, 2014.
For the current permit cycle, by December 1, 2024, notify Ecology of the city’s intent to pay into a collective fund to implement the following programs:

Regional status and trends monitoring
Stormwater management program effectiveness and source identification studies or conduct stormwater discharge monitoring.

Submit records of SWMP activities tracked and/or maintained in response to requests by the Stormwater Action Monitoring Coordinator.

Planned Activities

The city decided to opt to pay into the collective fund by December 1, 2024 and start contributing to the fund beginning in August 2025. For the pervious permit cycle, the city plans to pay $16,987 for regional status and trends monitoring and $31,045 for stormwater management program effectiveness and source identification studies by December 1, 2024.

Annual payments into the collective fund, starting in August 2025, include the following:

Regional status and trends monitoring: $26,875
Stormwater management program effectiveness and source identification studies: $39,775
Annual Total: $66,650
2024–2029 Phase II Permit Total: $333,250

REPORTING

This section provides a brief discussion of Phase II Permit reporting requirements, including planned activities.

2024-2029 Phase II Permit Requirements

Section S9 of the 2024-2029 Phase II Permit list the following requirements:

Submit an annual report to Ecology no later than March 31 of each year (beginning in 2025).
Keep all records related to the NPDES Phase II Permit and the SWMP for at least 5 years after the expiration date of the Permit.
Make records related to the NPDES Phase II Permit and the SWMP available to the public at reasonable times during business hours.

Planned Activities

The city plans to meet all the reporting requirements outlined in the 2024-2029 Phase II Permit.

APPENDIX A

Coordination Mechanisms

External Coordination Mechanisms

The city coordinates with adjacent jurisdictions as needed to control pollutants between physically interconnected MS4s and coordinates stormwater management activities to avoid conflicting plans, policies, and regulations.

The Surface Water Utility (SWU) Engineering and Surface Water (SW) Maintenance Sections implement procedures to coordinate with adjoining jurisdictions to address pollutants entering or leaving the city’s MS4.

The SWU Engineering Section coordinates stormwater management activities for shared watersheds through participation in the WRIA 8 Salmon Recovery Council, WRIA 9 Watershed Ecosystem Forum, and Our Green/Duwamish Watershed Stormwater Strategy.

Internal Coordination Mechanisms

The city formed a NPDES Interdepartmental Team composed of staff from select departments, divisions and sections in the fall of 2014. The Interdepartmental NPDES Stormwater Planning Team formed by August 1, 2020 and is indicated by an asterisk.

Public Works Department

Surface Water Utility (SWU) Engineering Section*
Public Works Maintenance Division
Surface Water (SW) Maintenance Section*
Renton Municipal Airport Division
Transportation Planning Section*
Sustainability & Solid Waste Section
Water Utility Engineering Section
Facilities Division
Street Maintenance Section

Community and Economic Development (CED) Department

Development Engineering*
Planning*
Long Range Planning*
Construction Inspections
Building Inspections
Code Compliance

Parks & Recreation Department

Parks & Trails Division
Golf Course Division
Parks Planning & Natural Resources Division*

The Interdepartmental Team developed a permit compliance matrix that lists Phase II Permit requirements, Ecology deliverables or documentation in the Annual Report, task leads, task support, and deadlines. The Interdepartmental Team will continue to coordinate Phase II Permit implementation activities during the duration of the permit, to ensure that the city meets the requirements of the Phase II Permit.

2024 Stormwater Management Program Plan - Translatable

2024

STORMWATER MANAGEMENT PROGRAM PLAN

CITY OF RENTON MUNICIPAL STORMWATER PROGRAM

City of Renton 1055 South Grady Way
Renton, Washington 98057

March 21, 2024

CONTENTS

Comprehensive Stormwater Planning

Public Education and Outreach

Public Involvement and Participation

Recommended Activities

2019-2024 Phase II Permit Requirements

MS4 Mapping and Documentation

Illicit Discharge Detection and Elimination

Controlling Runoff from New Development, Redevelopment, and Construction Sites

Operations and Maintenance

Source Control Program for Existing Development

Total Maximum Daily Load Requirements

2019-2024 Phase II Permit Requirements

Monitoring

2019-2024 Phase II Permit Requirements

Reporting