Unified Stormwater Rule

The Unified Stormwater Rule updated and aligned water quantity requirements in the city’s combined sewer drainage areas with water quality requirements in separately sewered drainage areas, providing a comprehensive, citywide stormwater management policy for public and private development. The NYC Stormwater Manual provides a comprehensive overview of NYC stormwater management requirements and design guidance for developers, designers, and engineers who work on projects that must comply with the requirements of Site/House Connection Proposal Certifications and Stormwater Permits.

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

New York City Stormwater Manual

The NYC Stormwater Manual provides technical guidance that emphasizes a retention-first, green infrastructure approach to stormwater management practice selection and design.

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