Unified Stormwater Rule

rain water flowing down a street and into a rain garden

The proposed Unified Stormwater Rule amendments were publicly reviewed then published as final on February 15, 2022. This Rule includes amendments to Chapter 31 and Chapter 19.1 of Rules of the City of New York, changing requirements for how stormwater is managed on all new and redevelopment sites that discharge to City sewers. 

Chapter 31 updates stormwater quantity and flow rates for Site Connection Proposals and House Connection Proposals. 
Chapter 19.1 expands the Stormwater Construction Permitting Program, setting new thresholds for compliance and a new retention-first approach for design of post-construction stormwater management practices (SMPs).
Chapter 19.1 also includes a new New York City Stormwater Manual to provide guidance for permit applicants.

Download a list of Unified Stormwater Rule Frequently Asked Questions and Responses compiled during the public comment period.

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New York City Stormwater Manual

The New York City Stormwater Manual provides technical guidance for developers, designers, and engineers who will work with DEP on stormwater permitting.

Download the New York City Stormwater Manual

Download Appendix A: Stormwater Management Practice Hierarchy Checklist
Download Appendix B: Nitrogen No Net Increase Calculator Guide Placeholder
Download Appendix C: Stormwater Management Practice Siting Criteria
Download Appendix D: Stormwater Management Practice Sizing Example
Download Appendix E: Site Design Example
Download Appendix F: Controlled Flow Pump Workbook
Download Appendix G: Detention Series Workbook
Download Appendix G: Detention Series Examples
Download Appendix H: Right of Way Guidance Materials
Download Appendix H: Right of Way Stormwater Management Practices Data Tracking Form Workbook

Public Presentations

Watch the Unified Stormwater Rule: Informational Briefing
Download the Unified Stormwater Rule: Informational Briefing Presentation