Johnson Environmental Services | Wastewater Compliance & Consulting

Changes to Indiana Stormwater General Permit

Published January 12, 2025

Indiana is revising its Stormwater General Permit to better align with federal environmental regulations. These updates impact businesses operating under stormwater discharge permits and require adjustments to compliance practices.

1. Key Changes in the Stormwater General Permit

The new permit introduces additional monitoring requirements, reporting obligations, and stricter compliance measures.

Notable Changes Include:

Introduction of subsectors based on Standard Industrial Classification (SIC) codes.
Requirement for quarterly visual assessments at each discharge outfall.
Mandatory submission of annual compliance reports.
More stringent best management practices (BMPs) to prevent pollution.

2. How These Changes Impact Businesses

Facilities that previously qualified for minimal reporting may now need to conduct additional monitoring and submit enhanced compliance reports.

Industries Most Affected:

Manufacturing and processing plants with stormwater discharge.
Construction companies working on sites exceeding one acre.
Facilities with historical compliance issues requiring corrective action.

3. Steps to Ensure Compliance

Businesses should proactively review their stormwater management plans and update processes accordingly.

Recommended Actions:

Review your existing stormwater pollution prevention plan (SWPPP) for necessary updates.
Ensure proper documentation of stormwater monitoring and sampling.
Train employees on new compliance and reporting obligations.

4. Deadlines and Transition Period

Facilities currently covered under the old permit must transition to the new requirements within the allotted timeframe.

Important Deadlines:

New Notice of Intent (NOI) submissions due within 180 days of the new permit's effective date.
First annual report submission required within 365 days.

5. Resources for Assistance

Businesses can seek guidance from IDEM’s compliance resources or consult environmental professionals for tailored support.

Helpful Resources:

Indiana Department of Environmental Management
Professional consultants specializing in stormwater compliance.
Training programs on new permit requirements.

Conclusion

Adapting to the changes in Indiana’s Stormwater General Permit requires a proactive approach to compliance. By understanding the new requirements, updating stormwater management practices, and seeking expert guidance, businesses can maintain regulatory compliance and avoid potential violations.

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