Accessory Dwelling Units

According to (NH) SB 146, “accessory dwelling unit” means a residential living unit that is within or attached to a single-family dwelling, and that provides independent living facilities for one or more persons, including provisions for sleeping, eating, cooking, and sanitation on the same parcel of land as the principal dwelling unit it accompanies.

These have often been referred to as “mother-in-law apartments” or “granny flats.”  In some cases, they may be detached – over a garage or in an outbuilding on the property, for example.


Governor Maggie Hassan signed this bill on March 16 2016  It will go into effect on June 1, 2017, so communities have a full year to prepare.


For an overview of the ADU concept in NH, go here:  Accessory Dwelling Units overview


For the full bill, go here


For a summary of the bill,  go here: SB 146 summary


Here is an example of one town’s ADU ordinance (Londonderry):  Londonderry ADU zoning


To view Ben Frost’s overview and summary of the bill,  go here:  ADU’s defined (including SB 146) – Ben Frost presentation March 17 2016 for Plan NH workshop

To view the Londonderry story, go here:  ADU regulations in Londonderry – presentation for Plan NH March 17 2016.