Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Smart Growth / Smart Energy Toolkit Accessory Dwelling Units (ADU)

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units An Accessory Dwelling Unit is a secondary housing unit on the same property as a main residence. ADUs are also called accessory apartments, in-law apartments, family apartments, or secondary units. ADUs are not duplexes : –Size of ADU is subsidiary to the main residence –Owner of ADU usually lives on the property ADUs are self-contained What is an ADU?

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Why consider an ADU bylaw? Shrinking household size Rising real estate costs Aging population Neighborhood stability Character of neighborhoods Environmental benefits

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units What does it do for you? Municipality: –Increases tax revenue –Minimizes subsidies required for affordable units –Maximizes use of existing infrastructure and services –Keeps growing and aging families together –Preserves existing homes and historic structures –Promotes safe and stable neighborhoods

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Who benefits from ADUs? Homeowners – rental income Middle-income tenants – more units Local businesses – employee housing Real estate firms – rental stock Residential contractors – remodeling Lending institutions – home improvement loans

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Affordable ADUs Local Initiative Program can be an instrument for affordability ADU qualification conditions for MA Subsidized Housing Inventory (SHI) –Unit approved by local bylaw and DHCD –Unit occupied by income-eligible tenant (≤80% of area median income) –Unit rented at affordable price over term of control For SHI details, contact Department of Housing and Community Development at

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Who typically chooses to build ADUs? Older singles/couples Middle-aged "empty nesters" Younger singles/couples Single working parents People who travel often

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Apartments in single-family homes Additions to homes Conversion of garages or barns Free-standing cottages Designed into new construction How and where are ADUs built?

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units ADUs and Neighborhood Type Traditional Neighborhood Blocks Features: Shallow lots, with or without alley Carriage houses and garages at the back of the lot Original carriage houses small single bay buildings ADUs sited along alley frontage or rear property line

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units ADUs and Neighborhood Type Transitional Neighborhood Blocks Features: Pre-war grid blocks with pre- and post war housing Deep lots Garages located in rear yards ADUs placed within garage zone in rear yards

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units ADUs and Neighborhood Type Suburban Neighborhood Blocks Features: Cul-de-sac blocks Small yards Parking in front of lot with 20’ driveway parking ADUs sited in rear lot areas on bigger lots and/or garage conversions

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units ADU Option 1: Apartments within Single-Family Homes

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units ADU Option 2: Additions to Single-Family Homes

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units ADU Option 3: Conversion of Garages, Barns, Outbuildings

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units ADU Option 4: Construction of New Outbuildings

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units ADU Option 5: Designed into New Construction

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Regulation of ADUs Zoning ordinance/bylaw –Specifies ADU conversion standards As-of-Right –For interior alterations Special Permit –For exterior changes and out buildings Licensing –Periodic appraisal of ADU via renewal or for change in ownership

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Summary of ADU Benefits Creates new housing using existing infrastructure and services Reduces energy consumption Generates community dollars through home equity Reduces costs for the elderly Preserves housing stock and neighborhood stability

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Selected MA communities with ADU bylaws Case studies –Pelham, rural community –Lexington, suburban community –Northampton, urban community

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Additional Information MA Housing Partnership (MHP) MA Department of Housing and Community Development (DHCD) Background on Subsidized Housing Inventory Older Americans Act website

Smart Growth / Smart Energy Toolkit Accessory Dwelling Units Additional Information ‘Taking the Initiative – A Guidebook on Creating Local Affordable Housing Strategies’, CHAPA and MHP, Chapter 3, pp (March 2003) taking_the_initiative_guidebook__ch._111.pdf taking_the_initiative_guidebook__ch._111.pdf ‘Granny Flats Add Flexibility and Affordability’, New Urban News Ithaca, NY, New Urban Publications, (2001) ‘Accessory Apartments’, Leo L. Cram, Missouri Gerontology Institute, University of Missouri (1993) aging/gg0014.htm aging/gg0014.htm