Connecticut Stormwater Quality Manual

The Department of Energy and Environmental Protection and the Connecticut Council on Soil and Water Conservation partnered on the revisions for the Connecticut Guidelines for Soil Erosion and Sediment Control and the Connecticut Stormwater Quality Manual (below). 

The revisions to these documents included:

• Reformatting the Stormwater Quality Manual to focus on function
• Updating the 90th percentile water quality storm and design storms with more recent data.
• Including the Environmental Protection Agency’s performance curves to aide in evaluating the appropriate selection and sizing of best management practices for site-specific conditions.
• Incorporating updated Low Impact Development guidance into the body of the document to be consistent with permit requirements
• Adding workflow processes and checklists to streamline site design to meet a variety of stormwater quality programs and promote site design to preserve on site assets.
• Updating technical design details.
• Updates to provide better consistency between the two guidance documents.

Stormwater Quality Manual

The Connecticut Stormwater Quality Manual provides guidance on the measures necessary to protect the waters of the State of Connecticut from the adverse impacts of post-construction stormwater runoff. This manual focuses on site planning, source control, and stormwater treatment practices and is intended for use as a planning tool and design guidance document by the regulated and regulatory communities involved in stormwater quality management.

View the Full Connecticut Stormwater Quality Manual

Or choose one or more of the specific sections to download separately:

• Title Page, Acknowledgements and Table of Contents
• Background Chapters 1-3 (Introduction, Stormwater Impacts, and Preventing and Mitigating Stormwater Impacts)
• Design Chapters (Set 1) 4-7 (Stormwater Management Standards and Criteria, Low Impact Development Site Planning and Design Strategies, Source Control Practices and Pollution Prevention, and Overview of Structural Stormwater Best Management Practices)
• Design Chapters (Set 2) 8-11 (Selection Considerations for Stormwater BMPS, Stormwater Retrofits, General Guidance for Stormwater Infiltration Systems and Proprietary Stormwater BMPs)
• Design Chapters (Set 3) 12 (Stormwater Management Plan) and 13 (Structural Stormwater BMP Guidance)
• Appendices

 

Content Last Updated February 25, 2026