Septic system requirements in Connecticut
What landplan.io applies when it designs a septic system in Connecticut: the system types allowed, tank sizes, setbacks and soil loading rates, with what septic products cost there.
Updated
Design a septic system for an address in Connecticut
Reviewed landplan.io designs by Connecticut's own rules, which our staff reviewed against the state's regulations. Last published 5 October 2026.
Septic systems allowed in Connecticut
The system types landplan.io permits in Connecticut:
- Elevated Sand Mound System
- Low-pressure distribution (LPD) System
- Leaching Trench System
- Leaching Gallery
- GST System
- Leaching Pit System
- Discharging System
Septic tank size in Connecticut
The daily design flow of a home: 150 gal/day per bedroom, at least 240 gal/day. The septic tank is sized from that flow:
| Daily design flow | Minimum tank |
|---|---|
| up to 450 gal/day | 1,000 gallons |
| 450 to 525 gal/day | 1,125 gallons |
| 525 to 600 gal/day | 1,250 gallons |
| 600 to 675 gal/day | 1,400 gallons |
| 675 to 750 gal/day | 1,525 gallons |
| 750 to 825 gal/day | 1,650 gallons |
| 825 to 900 gal/day | 1,775 gallons |
| 900 to 975 gal/day | 1,900 gallons |
| 975 to 1,050 gal/day | 2,025 gallons |
| 1,050 to 1,125 gal/day | 2,150 gallons |
| 1,125 to 1,200 gal/day | 2,275 gallons |
| 1,200 to 1,275 gal/day | 2,400 gallons |
| 1,275 to 1,350 gal/day | 2,525 gallons |
| 1,350 to 1,425 gal/day | 2,650 gallons |
| 1,425 to 1,500 gal/day | 2,775 gallons |
Septic setbacks in Connecticut
| From | To | Distance |
|---|---|---|
| Polygon | Existing Septic Component to be Abandoned | 5 ft |
These are the values the landplan.io design engine applies in Connecticut. Confirm a design with the Connecticut health department or your county's before you build.
Parcel data in Connecticut
landplan.io has parcel boundaries for 9 of Connecticut's 9 counties: the counties where 100% of the state's people live. Type an address there and the design starts from the parcel.
Septic companies, designers and jobs in Connecticut
- Septic companies and distributors in Connecticut (42)
- Septic designers in Connecticut
- Septic design jobs in Connecticut
Where the rules come from
The regulations and documents landplan.io's Connecticut rules are read from:
- Public Health Code Sections 19-13-B100a and 19-13-B103 (On-site Sewage Disposal Systems with Design Flows of 5,000 Gallons per Day or Less) (Regs. Conn. State Agencies §19-13-B100a; §19-13-B103 through B103f)
- Technical Standards for Subsurface Sewage Disposal Systems (incorporated by reference into the Public Health Code) (Technical Standards for Subsurface Sewage Disposal Systems, adopted pursuant to Regs. Conn. State Agencies §19-13-B103d)
Septic rules by county in Connecticut
- Fairfield County
- Hartford County
- Litchfield County
- Middlesex County
- New haven County
- New london County
- Tolland County
- Windham County
Questions
What septic systems are allowed in Connecticut?
landplan.io permits these system types in Connecticut: Elevated Sand Mound System, Low-pressure distribution (LPD) System, Leaching Trench System, Leaching Gallery, GST System, Leaching Pit System and Discharging System.
What size septic tank do I need in Connecticut?
landplan.io sizes the septic tank in Connecticut from the daily design flow: up to 450 gal/day: 1,000 gallons; 450 to 525 gal/day: 1,125 gallons; 525 to 600 gal/day: 1,250 gallons; larger flows need larger tanks. A home's design flow is 150 gal/day per bedroom, at least 240 gal/day.
Does landplan.io have parcel data in Connecticut?
Yes, for 9 of Connecticut's 9 counties.