Environmental Engineering - Subsurface Sewage
An estimated 40% of Connecticut residents, close to 1.5 million people, live in homes served by on-site sewage systems. The vast majority of these sewage systems are conventional septic systems that are under the jurisdiction of the Local Directors of Health, and are the primary means of sewage disposal in rural and low density suburban areas. Septic systems also serve apartment buildings, schools, restaurants, and other commercial buildings in non-urban areas.
Septic systems that are properly designed, installed, and maintained provide a safe and efficient way of disposing domestic sewage. However, when sewage is discharged to antiquated or substandard sewage systems, such as cesspools, renovation of the wastewater by the soil may be incomplete. Sewage contains pathogens (disease causing organisms) and if improperly disposed may result in health hazards and nuisance conditions.
Did you know?
Common household leaks can add
hundreds of extra gallons of water
every day, stressing your septic system. Overloading your septic system with
water is a leading cause of failure. Save water and support your septic system’s
health. For the long-term care of your system,
have your septic tank inspected and pumped
out by a CT licensed septic tank cleaner or installer as
needed (on average every 3-5 years).
Click on the SepticSmart icon below for more information.
Septic systems on sites with design flows of 7,500* gallons per day (GPD) and less are permitted by the Local Director Health. Additionally, plans for large septic systems serving buildings with design flows of 2,000 to 7,500 GPD must be approved by the CT Department of Public Health. Septic systems, defined as subsurface sewage disposal systems, are regulated by Public Health Code (PHC) Section 19-13-B103 and the associated Technical Standards for Subsurface Sewage Disposal Systems (Technical Standards). Local Health Department contact information. Septic systems on sites with design flows exceeding 7,500 GPD, alternative sewage disposal systems, and community sewage systems are permitted by the CT Department of Energy and Environmental Protection (CTDEEP).
*See Circular Letter 2017-17 that concerns new legislation (Public Act 17-146, Section 30) that affected subsurface sewage disposal system jurisdiction.
the Environmental Engineering Program at: dph.environeng@ct.gov
Additional Online Resources:
Statutes, Regulations and Technical Standards for Subsurface Sewage Disposal Systems
*2024 Technical Standards for Subsurface Sewage Disposal Systems* (01/01/2024)
- Technical Standards 2024: Updates Highlighted (01/01/2024)
- Summary of 2024 Technical Standards Updates (01/01/2024)
- 2024 Technical Standards Update Presentation (02/27/2024)
- Connecticut Public Health Code - Section 19-13-B100a Building Conversions and Additions
- Sewage System Installer and Cleaner Statutes
- Design
Manual - Subsurface Sewage Disposal Systems for Households and Small Commercial Buildings
- Design Manual Part 1 (General Design Principles)
- Design Manual Part 2 (Specific Design Considerations)
Historical Technical Standards
Exception Applications
All applications are for Local Health Department use only.
We encourage electronic completion and submission utilizing the Electronic Form (eform) including scanned supporting documentation. Please see Circular letter 2024-29 Revised Exception Application Forms, Circular Letter 2011-70 Water Supply Well Separation Distance Exceptions and/or Circular Letter 2012-42 Central System Exceptions in the Environmental Engineering section under Environmental Health Section-Publications for additional requirements.
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Central System Exception
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Easement Exception
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Well Exception
Water Treatment Wastewater (WTW)
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USDA Rural Development: Utilities
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USDA Rural Development: Single Family Housing Loans and Grants
Inspections of Existing Septic Systems
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Haynes Materials Seymour Quarry (Not selling as of 7/1/2022)
Product Approvals
DPH Code Advisory Committee (CAC)
Historic CAC Agendas and Meeting Records:
-2023 Updated Summary of Proposed Revisions 11/18/2022
CAC Agenda 8/30/2022 (meeting link included)
Installer/Cleaner Exam Information