Septic system requirements in Massachusetts

What landplan.io applies when it designs a septic system in Massachusetts: the system types allowed, tank sizes, setbacks and soil loading rates, with what septic products cost there.

Updated 5 October 2026

Design a septic system for an address in Massachusetts

Reviewed landplan.io designs by Massachusetts's own rules, which our staff reviewed against the state's regulations. Last published 5 October 2026.

6system types permitted

1,000 gallonssmallest septic tank

35septic companies located here

14 of 14counties with parcel data

Septic systems allowed in Massachusetts

The system types landplan.io permits in Massachusetts:

Elevated Sand Mound System
Subsurface Pressure Trench System
Subsurface Trench System
Infiltrator Advanced Treatment Leachfield
Infiltrator Advanced Enviro-Septic® (AES)
Discharging System

Septic tank size in Massachusetts

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:

Septic Tank: minimum size by daily design flow
Daily design flow	Minimum tank
up to 240 gal/day	1,000 gallons
240 to 360 gal/day	1,500 gallons
360 to 600 gal/day	2,000 gallons
600 to 720 gal/day	2,500 gallons
720 to 840 gal/day	2,750 gallons
840 to 920 gal/day	3,000 gallons
920 to 1,040 gal/day	3,250 gallons

Septic setbacks in Massachusetts

Minimum distances
From	To	Distance
Polygon	Existing Septic Component to be Abandoned	5 ft

These are the values the landplan.io design engine applies in Massachusetts. Confirm a design with the Massachusetts health department or your county's before you build.

Parcel data in Massachusetts

landplan.io has parcel boundaries for 14 of Massachusetts's 14 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 Massachusetts

Where the rules come from

The regulations and documents landplan.io's Massachusetts rules are read from:

The State Environmental Code, Title 5: Standard Requirements for the Siting, Construction, Inspection, Upgrade and Expansion of On-site Sewage Treatment and Disposal Systems and for the Transport and Disposal of Septage (310 CMR 15.000)

Septic rules by county in Massachusetts

Questions

What septic systems are allowed in Massachusetts?

landplan.io permits these system types in Massachusetts: Elevated Sand Mound System, Subsurface Pressure Trench System, Subsurface Trench System, Infiltrator Advanced Treatment Leachfield, Infiltrator Advanced Enviro-Septic® (AES) and Discharging System.

What size septic tank do I need in Massachusetts?

landplan.io sizes the septic tank in Massachusetts from the daily design flow: up to 240 gal/day: 1,000 gallons; 240 to 360 gal/day: 1,500 gallons; 360 to 600 gal/day: 2,000 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 Massachusetts?

Yes, for 14 of Massachusetts's 14 counties.