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.

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.

For general questions and to receive program notifications please e-mail the Environmental Engineering Program at: DPH.EnvironmentalEngineering@ct.gov

Additional Online Resources:


Statutes, Regulations and Technical Standards for Subsurface Sewage Disposal Systems


Design Manual - Subsurface Sewage Disposal Systems for Households and Small Commercial Buildings:

Back to topic index

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 2011-70 Water Supply Well Separation Distance Exceptions and/or Circular Letter 2012-42 Central System Exceptions in the Environmental Engineering section underEnvironmental Health Section-Publications for additional requirements.  



2019 Soils Training Workshop 

When: October 23-24, 2019 from 8:30am - 3:30pm

Where: DEEP Sessions Woods Wildlife Management Area (341 Milford St, Burlington, CT)

Registration: https://ceha.wildapricot.org/event-3449457

Training is RAIN OR SHINE. We will be getting dirty on both days, so be sure to bring your outdoor clothing and gear (bug spray, sun block, etc.) for field work.This year we have two tracks; a modified Traditional Soils Track (similar to previous years, with a few changes) and a Site Hydraulics Track (for those who have attended soils training in the past and focusing on more complicated soils, site hydraulics, and site designs). Both tracks will include instruction by Soils Scientist Peter Fletcher, indoor and outdoor hands-on instruction and demonstrations, and the opportunity to see leaching system products and ask questions of product manufacturers.

If you have trouble opening a document, please try a different browser such as Firefox or Chrome.


Water Treatment Wastewater (WTW)     

Back to topic index


Financial Assistance Programs

Back to topic index

Inspections of Existing Septic Systems

Manufactured Select Fill  

Back to topic index

Product Approvals           

Back to topic index

DPH Code Advisory Committee (CAC)

Technical Standards Revision Process and Code Advisory Committee (11/28/18) 

Meeting Agendas:

CAC Agenda 7/11/19

CAC Agenda 11/28/18 

CAC Agenda 06-14-18

CAC Agenda 11-16-17

CAC Agenda 09-14-17

CAC Agenda 06-08-17

CAC Agenda 03-02-17

CAC Agenda 10-13-16

CAC Agenda 6-29-16

CAC Agenda 11-19-15

CAC Agenda 6-11-15

CAC Agenda 10-30-14 

CAC Agenda June 26 2013         

CAC Meeting June 2011        

C D Plan Growth Management Principle #4 D Rural Areas 



Installer/Cleaner Exam Information