Septic system requirements in Nantucket County, Massachusetts

The septic rules landplan.io applies in Nantucket County, what a septic tank costs there, and the parcel data we hold.

Updated 5 October 2026

Design a septic system for an address in Nantucket County

Massachusetts's state rules apply in Nantucket County: landplan.io has no county rules of its own here. State rules: Reviewed See Massachusetts's rules

6system types permitted

1,000 gallonssmallest septic tank

Coveredparcel data

Septic systems allowed in Nantucket County

The system types landplan.io permits in Nantucket County:

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 Nantucket County

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 Nantucket County

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 Nantucket County. Confirm a design with the Massachusetts health department or your county's before you build.

Parcel data in Nantucket County

landplan.io has parcel boundaries for Nantucket County (93.1% of its area): type an address 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 Nantucket County, 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)

Near Nantucket County

Questions

What septic systems are allowed in Nantucket County?

landplan.io designs by Massachusetts's state rules there and permits: 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 Nantucket County?

landplan.io sizes the septic tank in Nantucket County 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 for Nantucket County, Massachusetts?

Yes: parcel boundaries cover Nantucket County (93.1% of its area).