CT DEEP Issues Notice of Tentative Determination to Renew the Comprehensive General Permit

The Connecticut Department of Energy and Environmental Protection (CT DEEP) has issued a Notice of Tentative Determination to renew the Comprehensive General Permit for Discharges to Surface and Groundwater. Public comments on the proposed renewal are due by January 23, 2026.

Facilities currently authorized under this permit (or those planning to be) should review the notice to understand how renewal of the permit may affect ongoing compliance obligations.

Note: A Notice of Tentative Determination is a preliminary decision issued by CT DEEP indicating its intent to renew or modify a permit. The notice opens a public comment period before the permit is finalized and does not represent a final agency decision.

Overview

The Comprehensive General Permit (GP) authorizes the discharge of the following wastewaters to a surface water or groundwater:

• Non-contact cooling or geothermal heat pump water
• Water treatment wastewater
• Hydrostatic pressure testing of natural gas and petroleum tanks and pipelines wastewater
• Potable water system maintenance of tanks and pipelines wastewater
• Hydrant flushing wastewater
• Boiler blowdown wastewater (to groundwater only)

Unlike the Industrial Stormwater GP and Wastewater GPs (for both SIU and NSIU discharges) recently issued by CT DEEP, the Comprehensive GP applies to non-stormwater discharges that do not fall under a more specific permitting category.

The Comprehensive GP serves as a catch-all authorization for a wide range of miscellaneous or site-specific non-stormwater discharges to surface water or groundwater that are otherwise not eligible for coverage under another GP.

Note: Facilities that discharge both stormwater and non-stormwater may require coverage under multiple permits, depending on the nature of their discharges.

Proposed Changes

Proposed changes of the reissued Comprehensive GP include but are not limited to:

• Modernized format and layout
• Removal of the 15% Instream Waste Concentration threshold for eligibility
• All discharges required to be submitted electronically via Discharge Monitoring Report (DMR), filed through NetDMR
• Incorporation of DEEP’s new online noncompliance reporting tools
• Adding pressure washing as a new category of discharge
• Facilities with water treatment discharges to groundwater required to submit and implement a plan for the installation of monitoring wells before the five-year term of the GP expires

Recommended Next Steps

Facilities that are subject to coverage under the Comprehensive GP should consider the following actions:

• Review the proposed renewal notice and supporting materials
• Confirm whether current operations rely on this permit
• Identify any provisions that may impact facility operations
• Submit written comments by January 23, 2026
• Monitor for issuance of the final permit and associated effective dates

Public Comment Period

Before making a final decision on this proposed general permit, DEEP’s Commissioner shall consider written comments that are received by the above deadline.

Written comments should be directed to:

James Creighton
Department of Energy and Environmental Protection
Water Permitting and Enforcement Division
79 Elm Street
Hartford, CT 06106-5127

or may be submitted via electronic mail to: james.creighton@ct.gov.

How Walden Can Help

Understanding permit applicability and future compliance obligations is critical to avoiding penalty fines and legal repercussions.

Walden’s environmental health and safety (EHS) team can assist with permit registration/renewals, evaluating discharge eligibility, updating compliance documentation, and more.

Contact us today at 860-846-4069 to discuss the GP in further detail.