Connecticut Department of Energy & Environmental Protection

The General Permit for Discharge from Subsurface Disposal Systems

The General Permit for Discharge from Subsurface Disposal Systems (Subsurface GP) provides a streamlined regulatory pathway for the discharge of domestic sewage to the groundwaters of the state. The permit is applicable to sites with a total aggregate design flow exceeding 7,500 gallons per day (GPD) that utilize conventional septic or community sewerage systems.

By establishing uniform effluent limitations and standardized operating requirements, the Subsurface GP ensures the protection of Connecticut's groundwater resources while providing a predictable and efficient authorization process for eligible facilities.

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The General Permit to Discharge from Subsurface Disposal Systems was issued October 13, 2021 and expires on October 12, 2031

Eligibility for Coverage

Coverage under the General Permit is available for both existing sites and new sites that discharge domestic sewage into the ground or a holding tank. Eligibility is primarily determined by the system type and total daily design flow, meaning the cumulative wastewater volume from all systems on a single property.

Eligible activates include:

  • Large-Scale Systems: Conventional septic systems with a combined design flow of more than 7,500 gallons per day (GPD) on one property.
  • Community Sewerage Systems: Any system serving two or more residential buildings in separate structure not connected to a municipal sewer, regardless of the design flow.
  • Holding Tanks: These are authorized under specific circumstances, such as addressing a failed or malfunctioning system or as part of an approved Wastewater Management Plan.

Application Forms and Required Submissions

  • Site Investigation
  • Application
  • Technical Plan
  • Wastewater Management Plan

If your project is...

Waste Management Plan

Standard Fee

Previously Authorized (No Changes)

Due within 1 year

$250

System Modification (Any Flow)

Required if flow increases

$250

Existing Site (> 7,500 GPD)

Due within 1 year

$3,000

New Site (Standard/No Change)

Required with Filing

$3,000

New Site (Expansion or Modification)

Required with Filing

$6,000

Schedule a DEEP Site Investigation

Before submitting an application and preparing plans, applicants must schedule a site investigation with the UIC Program Supervisor.

Email us: DEEP.UICPermitting@ct.gov Subject Line: "Site Testing"

Application

  • General Permit Application Form
  • Step-by-step Application User Guide

Technical Plan Submission Requirements

All Technical Plans must be prepared, signed, and sealed by a Professional Engineer (P.E.) licensed in the State of Connecticut.
Please note that blueprints of seals or signature are not accepted; original wet seals and signatures are required on every copy.

1. General Formatting & Standards
  • Engineering Standards: Must follow sound engineering practices and align with the approved (or proposed) Water Management Plan (WMP).
  • Required Details: North arrow (true, magnetic, or assumed), stable benchmarks, lot dimensions, and a comprehensive legend.
  • Location Maps: "Key" maps are required for large industrial, residential, or commercial sites.
2. Mandatory Site Information
  • Topography: Existing and proposed contours, including 25-50' downgrade areas and fill extensions.
  • Site Investigation: Locations of test pits, percolation holes, monitoring wells, ledge rock, and any historical "bury holes" or old foundations.
  • Separating Distances: Within a 200-foot radius of any proposed system, you must show:
    • Watercourses (streams, ponds, swamps).
    • Public water lines, wells (with protective radii), and storm drains.
    • Buried oil tanks or other potential pollution sources.
3. System Design & Specifications
  • Design Flow: Must include the basis for calculations (e.g., 150 GPD per residential bedroom).
  • System Layout: Detailed mapping of sewer lines, septic tanks, pump chambers, and leaching systems, including specific invert and bottom elevations.
  • Cross Sections: Representative views of proposed systems showing fill, ledge, and groundwater elevations.
  • Phosphorus Analysis: Required for all proposed systems.
  • Technical Specs: Detailed material specs for piping, septic tanks, grease traps, and pump models.
4. Required Professional Certification
  • The plan must include the specific certification language found in Section 4(c)(3)(B)(iii) of the General Permit, stating that the system, if properly maintained, will meet all discharge conditions.

Wastewater Management Plan

A Wastewater Management Plan is required for nearly every site authorized under this General Permit. It ensures that your system is managed responsibly to prevent the pollution of Connecticut's waters.

Schedule a DEEP Site Investigation

Before submitting an application and preparing plans, applicants must schedule a site investigation with the UIC Program Supervisor.

Wastewater Management Plan Submissions Deadlines

Project Category

Submission Deadline

New Site

With Registration: Must be submitted as part of the initial application package.

Existing Site (with Flow Increase)

With Registration: Required at the time of filing due to the change in design flow.

Existing Site (Modification Only; No Flow Increase)

Post-Approval: Must be submitted within 1 year of registration approval.

Existing Site (No Modifications)

Post-Approval: Must be submitted within 2 years of registration approval.
1. Preparation Standards
  • Professional Oversight: Must be prepared, signed, and wet-sealed by a Connecticut-licensed Professional Engineer.
  • Formatting: Any drawings must follow the Technical Plans requirements (specific scales and detail).
  • Certification: The plan must include the specific legal certification language from the permit, confirming the information is accurate and the system is designed to meet permit conditions.
2. What the WMP Must Contain

Your WMP is a comprehensive document that must include:

  • Site Description: Location, ownership, maps, and a summary of proposed activities.
  • Current Conditions: A history of the site's wastewater use, maintenance records, soil conditions, and groundwater depth/direction.
  • Mapping: Clear boundaries showing wetlands, watercourses, structures, and all existing system components.
  • Technical Analysis: A site-wide Nitrogen Dilution Analysis to ensure compliance with CT Water Quality Standards.
    • A comparison of existing systems against current technical requirements
    • An assessment of future wastewater needs and anticipated modifications
  • Management Strategy: An implementation schedule for inspections, monitoring, and maintenance.

How to Submit Your Application

The application process is a 5-step, time-sensitive process

Step 1 - Prepare

Review the permit and confirm eligibility requirements.

Step 2 - Complete the Application Form

Refer to the Application User Guide for step-by-step instructions and the list of required information needed to complete the form.

Step 3 - Submit the Application Transmittal Form

The Application Transmittal Form allows DEEP to track fee payments and match them to the correct application. The Permit Application Transmittal Form is required for this general permit and must be submitted with your permit-specific forms. Click to download the Word Doc or PDF version.

  • After completing the Application Transmittal Form, email it to: DEEP.CentralPermits@ct.gov
  • Important: Keep a copy of your records. You will receive a confirmation email with instructions for submitting payment and accessing the file transfer site. Once the Application Transmittal Form is submitted and payment, (if required) is received the remainder of the process is time-sensitive.
Step 4 - Upload Required Documents

Within 10 business days of submitting the Application Transmittal Form, upload all required documents to DEEP's File Transfer Protocol (FTP) site, File Sharing Website, using the instructions provided in your confirmation email.

Critical Deadline: Applications will be closed and rejected if required documents are not received within 10 business days. Submit documents as soon as possible after submitting the Application Transmittal Form and payment.

Step 5 - Application Review and Decision

DEEP will begin processing your application upon receipt of all required documents.

Fees

If your project is...

Description

Standard Fee

Minor / Modification

Existing site (any flow) with a system repair, modification, or community sewerage system.

$250

Standard / No Change

A new site or an existing site (>7,500 GPD) with no system modifications.

$3,000

Expansion / New Design

A new site involving system modifications or any project proposing an increase in design flow.

$6,000

Common Omissions

Common Omissions that result in processing delays or rejection include:

  • Secretary of State (SOTS) Mismatch: The registrant's name must exactly match the business name registered with the CT Secretary of State. Search for your business name to verify here: Secretary of State Business Search.
  • Missing Public Notice: For Individual Permits, proof of public notice (Attachment AA) published prior to submittal is mandatory.
  • Missing or Expired NDDB Letters: For sites located in Natural Diversity Areas, an NDDB Determination Letter is required to be submitted with the application. Do not submit "Preliminary Site Assessments". For more information and to see whether your site is located in an NDDB Area, visit the NDDB webpage: Natural Diversity Data Base and Environmental Reviews.
  • Missing Signatures: Both the applicant and the preparer of the application must sign the certification page.
  • Incomplete Nutrient Analyses: Applications for systems with design flows >2,000 GPD often fail to include the mandatory phosphorus sorption analysis and site-wide nitrogen dilution analysis in the Wastewater Management Plan to demonstrate compliance with Water Quality Standards.

Need to Make a Change?

Contact the UIC Program and submit the appropriate form before doing any of the following:

  • increasing wastewater flow
  • modifying treatment
  • expanding disposal areas
  • installing a replacement treatment system
  • transferring ownership
  • abandoning or closing a system

Unauthorized modifications to your flows or treatment systems before obtaining authorization may result in loss of permit coverage. Some changes require the submission of an updated Wastewater Management Plan or engineering designs, plans, and specs.

If you have coverage under a General Permit, use this form to request a modification:

General Permit Form to Discharge from Subsurface Disposal Systems

Don't forget to submit an updated Wastewater Management Plan with your General Permit modification request.

Additional Resources

NetDMR Resources

Mapping Resources

Contact Us

Have a question or need help with your permit?

Email us at DEEP.UICPermitting@ct.gov

 

Content Last Updated: May 21, 2026