Welcome to Minnesota Stormwater Manual Version 4.0 (beta). This website supports the Minnesota's Construction Stormwater and Municipal Separate Storm Sewer System programs and contains a wealth of information for stormwater managers and practitioners from throughout the state of Minnesota.
Information: This website contains data an information formerly housed on the Minnesota Stormwater Manual, version 3.0, 'the stormwater wiki'.
Why is MPCA making this switch? 
The wiki platform is an aging technology which has served us well, but which also has limitations impacting the site security and accessibility. In 2024, MPCA decided to move the stormwater manual to a more stable platform to mitigate the risk of losing manual content and to facilitate improved sight accessibility.
Work in progress on the new manual
Late in 2024, MPCA’s IT service completed the task of copying the stormwater manual database to the new website platform and since early 2025, a small crew at MPCA has been working to organize and review that content which includes over 1600 individual pages, over 2,000 image files, over 1,000 documents, and several times as many hyperlinks.
Given the enormity of the task and the limited time available to accomplish the transition, our work has been focused on content that is most frequently accessed by manual users. Our initial goals have been:
- To provide a functional, navigable website
- To clean up ‘translation errors’ (broken links, formatting glitches) that are the unavoidable result of moving content between different coding environments – especially for frequently used pages.
We appreciate your patience while this work continues!
Your content is here but it may look a little funny
For an interim period of time, you may encounter page that have not been updated to conform with the new format of the manual. Please know that we are going through the manual systematically to address these translation errors.
Future work
As we move beyond this critical work phase, intermediate goals for the Manual include:
- Further streamlining of content within topics
- Updated graphics with accessible formats
- Adding new and revised content that reflects current research, changes in regulations (when needed), and the needs stormwater managers and practitioners.
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Featured Content
- NEW
- Preview (Coming Soon)
- Green infrastructure updates
- Guidance for synthetic turf
- Low Salt Design
- Coming in 2026
- Simple Estimator version 4.0. The simple estimator has been revised to better conform with MS4 TMDL annual reporting requirements. We will be rolling this out ahead of MS4 TMDL annual reporting deadlines.
Important Terminology
The following terminology is used throughout this site.
- Warning: REQUIRED - Indicates requirements stipulated by the MPCA Construction General Permit (CGP) or other consistently applicable regulations
- REQUIRED - Indicates standards stipulated by the CGP or other consistently applicable regulations.
- HIGHLY RECOMMENDED - Indicates guidance or other information that is extremely beneficial or necessary but not specifically required by the MPCA CGP.
- RECOMMENDED - Indicates guidance or other information that is helpful but not critical.
We appreciate your feedback
Help us improve this resource: We continue to update this manual as resources allow and value your input. If you have comments or suggestions on the format or content in this manual, please send them to us using the feedback form link in the website footer.