City of Owatonna Stormwater Management

Construction Stormwater Webpage

Our Construction Stormwater webpage is the best resource for information regarding the Grading Permit and stormwater requirements for construction projects. We have recently reorganized, updated, and expanded our guidance documents that are available for use. 

Additionally, we are working on creating a “Developers Guide to Stormwater Management” that is expected to be released in early 2025. This document will summarize stormwater, construction, and grading permit requirements and help guide your team with planning for construction and development projects. 

Please make sure site designers are using current standards and guidance documents when preparing for site surveys, construction drawings, site plans, and grading permit applications. We recommend applicants routinely visit our website and reach out to us to ensure the most current versions are available to your project team for use. Please refrain from saving these documents to your personal computer, as they are updated from time to time. 

Each time a project team submits a grading permit application, please ensure the plans and details are reviewed against the standards and guidance documents. Any guidance document should bear the new City of Owatonna Logo and a date of 10/10/2024. 

The Minnesota Stormwater Manual is also a great tool for your use. 

Reminder – Scheduling Grading Permit Inspections

Please remember to email stormwater@owatonna.gov to schedule PW inspections, including re-inspections. The following inspections can be incorporated into the grading permit and scheduled as noted above:

• Initial and Final Stormwater Site Inspections (SWPPP Compliance, Grade & Stabilization)
• Right-of-Way Inspections (Sidewalk, Pavement Replacement, Driveways/Approaches, Curb & Gutter, Sewer Connections, boulevard establishment)

A minimum of 48-hour advance notice is required for all stormwater inspections. Keep in mind this does not mean an inspection will be performed within 48-hours. A confirmation email will be sent in response to inspection requests.

Please remember to include the following information in each request:

• Grading Permit Number
• Site Address
• Type of Inspection
• Any other information that will be useful to the inspector (timeframes, site conditions, etc.)

What is considered Fully Reconstructed? 

Projects considered full reconstruction are those which expose or disturb the in-situ, native, or existing subgrade soils. Existing site conditions, pavement sections, and soil depths vary widely from project to project. The City HIGHLY recommends performing soil borings or small test pits to verify the extent of construction that will be necessary to meet the intended project goal. We encourage this step to be taken well in advance to help guide conversations with property owners and plan for any stormwater improvements that may be required.

See the below illustrations of full and partial reconstruction depths: 

2025 MPCA NPDES/SDS MS4 General Permit Re-Issuance

The MPCA NPDES/SDS MS4 Permit is reviewed, revised, and re-issued every 5-years. The new MS4 Permit is expected to be reissued in late 2025. Two important Minimum Control Measures (MCMs) of the MS4 Permit which affect the construction and development industry are MCM 4 Construction Site Runoff and MCM 5 Post Construction Stormwater Management. Prior to reissuance a mandatory public review and comment period will be open. We encourage you to participate in this process once available by MPCA. Additional information can be found here: Municipal stormwater (MS4) | Minnesota Pollution Control Agency (state.mn.us)