Connecticut Department of Energy & Environmental Protection

General Pretreatment Permit for Non-Significant Industrial User Discharges to Publicly Owned Treatment Works (Non-SIU GP)

The Non-SIU General Permit authorizes the discharge of industrial process and non-process wastewater to a Publicly Owned Treatment Works (POTW) from facilities that are not classified as Significant Industrial Users (SIUs). 

Developed to ensure consistent regulatory oversight, the Non-SIU GP provides a streamlined permitting framework for industrial and commercial discharges that, while individually non-significant, may collectively impact municipal wastewater treatment systems. 

The Non-SIU GP supports the goals of the Connecticut Pretreatment Program by protecting wastewater infrastructure, safeguarding public health, and preserving environmental quality. Through uniform requirements and proactive management of smaller-scale dischargers, the Non-SIU GP strengthens the overall effectiveness of the state’s Pretreatment Program. 

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Non-SIU General Permit

Use the Pretreatment Permit Decision Chart to determine if this permit is right for you. 

**The General Pretreatment Permit for Non-Significant Industrial User Discharges to Publicly Owned Treatment Works was issued on October 29, 2025**

Tip: The permit includes Smart Navigation - integrated smart links for fast and seamless navigation. One-click access to key sections.

Notification Timeline & Deadlines

Notification Deadlines for Existing Permittees

Existing Permittees: Sites covered under the previous permit (MIU GP issued 2020) are required to register by March 1, 2026

Note: Interim permit coverage is provided as long as a complete and timely notification form is received

Notification for New Permittees

New sites must submit a notification form at least 60 days prior to initiating discharge

Existing permittees: within 90 days, submit by March 1, 2026. New Permittees; 60 days before discharge begins

Notification Process & How to Apply

Submittal of Notification Forms are now being accepted!

Explore the step-by-step Notification User Guide for instructions on how to prepare and submit the online Notification Form.

Submit a Notification Online

Non-SIU General Permit Requires a Notification, Not an Application.
Facilities that are not Significant Industrial Users fall under the Non-SIU GP, which requires only a Notification Form.

Why Only a Notification Is Required:

  • Non-SIU discharges are considered lower risk.
  • A detailed technical review is not necessary.
  • Submitting the Notification Form serves to inform the POTW/CT DEEP.
  • Coverage is typically immediate or quickly acknowledged, without formal approval.

Notification Includes:

  • Basic facility information
  • Description of the discharge
  • Certification that facility operations meet permit requirements

How to Submit your Notification Form

The notification process is a 5-step process

Step 1: Read General Permit. Step 2: Collect Information. Step 3: Complete Notification Form. Step 4: Submit to DEEP. Step 5: Submit to Potw authorities

 

Step 1 - Read the General Permit
Review the permit and confirm eligibility requirements

Step 2 - Collection Information
Refer to the Notification User Guide for step-by-step instructions and the list of required information needed to complete the form.

Step 3 - Complete the Online Notification Form
The Notification User Guide provides step-by-step instructions for filling out the online Notification Form. The form must be completed in one session. Here is a sample PDF copy of the questions that will be asked on the online Notification Form.

Step 4 - Submit the Notification Form to DEEP
When you complete the online Notification Form, it is automatically submitted to DEEP.

  • No Approval: DEEP does not issue an approval for this notification.
  • Confirmation: You will receive a confirmation email containing a PDF copy of your completed Notification Form sent to the Applicant email address provided on the form.
  • No Fee: There is no charge from DEEP to submit this Notification.
  • DEEP's Role: DEEP will retain a copy of this form but will not issue any further approval based on this submission (refer to "What to Expect Upon Submission of the Notification").

Step 5 - Submit the Notification Form to the POTW Authority(ies)
After receiving your confirmation email, you must provide a copy of the completed PDF Notification Form to the relevant Publicly Owned Treatment Works (POTW) Authority(ies).

  • Recipient: Send the form to the POTW Authority that will be receiving the wastewater and any other POTW Authority conveying the wastewater (if different).
  • Local Requirements: Each POTW Authority has its own local procedures for reviewing and processing Notifications, including potential local fees.
  • Action Required: Contact the applicable POTW Authority(ies) directly for their specific submittal instructions, local requirements, and any associated fees.

What to Expect Upon Submission of the Notification

DEEP will retain a copy of this Notification Form and will not issue any further approval or acknowledgment. The Applicant remains responsible for complying with all terms and conditions of the General Permit. Any instances of permit noncompliance must be reported to DEEP using the online Noncompliance Reporting platform, available at: 

Noncompliance Notification Form
Noncompliance Follow-Up Report Form

Need Assistance with the Online Notification Form

For questions related to the permit:
DEEP Pretreatment Team - DEEP.Pretreatment@ct.gov

For Technical Issues with the online application system:
DEEP IT Support Team - DEEP.helpdesk.footprints@ct.gov

Due to anticipated high volume of inquiries, responses may take up to 2-3 business days. Your patience is appreciated.

When to Submit a Notice of Change 

If you are making changes to your site or discharge, you must submit a Notification of Change to both DEEP and the POTW.

To streamline this process, the Notice of Change form is the same as the standard Notification Form - simply check the appropriate box to indicate the change.

Reason for Submittal

Description / Trigger

Ownership Change

Ownership has changed after the initial notification of discharge.

Correction of Information

Notification form contains inaccurate or misleading information that must be corrected.

Significant Facility Modifications

Any change affecting the nature, volume, or characteristics of the discharge (see details below).

Variance Request

Permittee requests a variance from an effluent limitation or other condition of the permit.

New Applicant

Submitting screening results as part of an initial application for coverage.

Change in Activity or Pollutant Loading

Change in the process generating the discharge or in the pollutant concentration of an existing pollutant.

New Source of Water

Introduction of a new water source into the process.

New Pollutant

Introduction of a pollutant not previously reported in the initial Notification Form.

Change in Flow

Increase or decrease in the maximum daily discharge flow.

Relocation of Monitoring Point

Moving an existing sampling or monitoring location.

Treatment System Modification

Expansion, replacement, or alteration of the wastewater treatment system.

Where to Submit

Recipient

Description

DEEP

Submit using the Online Notification Form

POTW Authority

Submit a copy to each applicable municipal POTW that conveys or receives the discharge.

Permit Conditions for Industrial Users

The following conditions apply to industrial users authorized under the General Pretreatment Permit for Non-Significant Industrial User Discharge to Publicly Owned Treatment Works (Non-SIU GP):

pH Limit Compliance Schedule

  • Existing permittees (covered under the 2020 General Permit) have two years from the effective date of this General permit to achieve compliance with the required pH limits of 5.5-10.0 standard units.

PFAS Identification and Minimization Plan

  • Industries with a known or potential presence of per- and polyfluoroalkyl substances (PFAS) must develop and implement a PFAS Source Identification and Reduction Plan.

Discharge Sampling Requirements

  • Sampling must be conducted at least annually for all authorized discharges, in accordance with applicable monitoring requirements.

Conditions and Best Management Practices (BMPs)

  • The General Permit establishes specific conditions and BMPs applicable to each type of discharge to ensure protection of the POTW and the environment.

Guidance for POTWs

Non-SIU General Permit Implementation Guidance for POTWs

The Pretreatment Program reissued the Non-SIU GP with major updates that will provide key benefits to POTWs:

  • Enhanced infrastructure protection and operational control
  • Comprehensive pollutant monitoring and source identification
  • Improved administrative oversight and data collection
  • Streamlined digital application submissions

In order to assist POTWs with these updates, the Pretreatment Program has developed guidance documents which outline the following topics:

  • Key responsibilities in implementation
  • An action plan to ensure compliance and readiness
  • Compliance assistance tools
  • Additional resources

Guidance for POTWs: The 2025 Non-SIU General Permit

Quick Non-SIU Reference Guide for POTWs

Additional Resources and Contact Information

Pretreatment Program
Pretreatment Program Compliance Assistance
Industrial Wastewater

Contact Us: 
Have a question? Need help with your permit? We're here to help.

Pretreatment Program Staff:
Connecticut Department of Energy & Environmental Protection (DEEP)
Email: DEEP.Pretreatment@ct.gov

 

Content Last Updated: December 12, 2025