Besides dimensional standards, zoning also lists the allowable uses on lots in each zoning district. Zoning in suburban and rural areas has been used at times to exclude lower income individuals and renters by only allowing single-family residences, requiring large minimum lot sizes and even mandating minimum home size.  

The Missing Middle

Missing Middle Housing is a concept born from a general lack of home types, especially those that are affordable and located within a walkable neighborhood. This term was coined by Opticos Design, referring to home types, such as duplexes, triplexes, cottage courts and row houses, that are often not allowed under zoning regulations.

In Vermont, mobile or manufactured homes outside of manufactured home parks are required by law to receive the same treatment under zoning as traditional construction. In contrast, New Hampshire state law requires municipalities to allow manufactured housing in some but not all residential districts to allow for realistic opportunities for the development and expansion of manufactured housing parks (NH RSA 674:32). Both mobile homes and mobile home parks represent a needed affordable housing option, and a significant part of the current affordable stock.  

In general, most zoning bylaws do not account for other types of housing that are needed or desired (e.g. “the missing middle”). In fact, many bylaws only allow single-family dwellings and accessory dwelling units as permitted residential uses. Two-family dwellings, multi-family dwellings, and mobile home parks are often restricted as to where they can locate, and commonly require additional levels of review.  Other, less common, housing types are rarely specifically addressed (See Housing Types summary). In more dense areas, mixed-use structures that are part commercial and part residential may not be allowed or require additional levels of review and applicable standards. 


  1. Specifically allow three- and/or four-unit (multifamily) dwellings as a permitted use within village districts (i.e. making those smaller developments require an easier review process than larger multi-family dwellings, which might require site plan or conditional use review).   
  1. Establish other desirable housing options as specifically allowable land uses in applicable zoning districts, such as row houses, boarding houses, co-housing and bungalow courts.  
  1. Simplify the development review process for dwellings. Consider which multi-family and commercial uses are desirable, especially in village districts, and remove the conditional use and special exception requirement.  

New Hampshire state law requires the allowance of at least one ADU for any single-unit home in a district in which single-unit homes are a permitted use. In Vermont, one ADU is allowed for a single-family house as a permitted use. Many local regulations limit the size of accessory dwelling units to be 30% of the square footage of the primary dwelling, which can be a problem, especially for smaller primary homes.   

In Vermont, current law on ADUs requires that the owner live in either of the units. In New Hampshire, many municipalities only allow an attached ADU, although expanding to allow detached would improve feasibility, especially for older residents who prefer detached buildings. 


  1. Specifically allow detached ADUs in New Hampshire. 
  2. Pre-existing buildings, such as carriage houses and garages, should be allowed to be converted to an accessory dwelling even if they do not meet other dimensional requirements. 
  3. Allow the owner to live in either the primary home or the accessory dwelling unit. 
  4. Enable larger accessory dwelling units, especially for smaller primary homes. (For more information, see Zoning for Great Neighborhoods)  

Tiny houses can provide an affordable housing option but have not been clearly defined for local review and are not currently allowed in New Hampshire. Tiny houses generally are 600 square feet or less in footprint and can be placed on wheels or a foundation.  


  1. Specifically define tiny houses in your zoning regulations and indicate where they are allowed, what standards apply, and what review process is required. Consider allowing tiny home subdivisions/developments with regulations similar to mobile home parks.  

Many bylaws assume that a building is only one kind – residential or commercial. A mixed-use building has more than one kind of use, and an especially useful form for housing in downtowns is first floor commercial and upper story residential. In smaller villages this might be office/apartments. Parking for such buildings can be minimized as residents leave while workers arrive.  

Many times, even in rural areas, there are existing larger buildings that can be reused as mixed- uses or as purely residential in a form that would not generally be permittedSuch ‘adaptive reuses can take individual buildings, such as barns and vacant commercial buildings, and redevelop them as several housing units. By limiting adaptive reuse to pre-existing buildings, a community can keep such large buildings from proliferating in district where they would be out of place, but also put those that do exist back into productive use.  


  1. Allow mixtures of uses in a single building, as well as adaptive reuse of existing buildings with more housing units than would otherwise be allowed in the district. 

Our communities have residents that need housing that provide support services either through on-site or visiting staff, as well as the building itself. These may be for short-term or long-term stays. These include housing for those with mental health or substance abuse issues, transitional housing for ex-offenders, shelters, or other individuals that are difficult to house.    


  1. Work with local supportive services to ensure that local zoning allows and defines supportive housing options, and in a way that proactively addresses the community’s need for this type of housing. 

Communities are enabled to allow less conventional types of housing developments (such as co-housing, clustered housing/conservation subdivision, or Planned Unit Developments (PUDs)), but local bylaws often do not allow developers that option.  While these uses are more complex to administer, they can provide needed housing. 


  1. Add PUDs and other types of housing development where land and/or buildings may be owned singly or in common. 
  2. Provide density bonus for those housing projects that provide affordable units