General Zoning Considerations & Definitions

Types of housing:

  • Single-family home – 1 unit on one lot
  • Duplex – 2 units on one lot
  • Accessory Apartments/Dwelling Units (ADUs) –also often identified as in-law apartments are a current legal way for single-family dwellings to create a subordinate dwelling unit on the property. 
  • Triplex – 3 units on one lot – they are often in the form regionally known as triple deckers
  • Multi-family – 3 or more units, though it is colloquially used to mean larger apartment buildings 


Terms you might hear in discussions related to housing--

Transit-oriented development: Mixed residential density development centered on existing or new transportation services including bus service, rail, or bike paths. For example, in Reading this could mean building more apartments near the train depot.

Missing Middle/Gentle Density: Refers to building types such as duplexes, triplexes, and small apartment buildings up to about 10 units that provide diverse housing options. They are termed “missing” because they are typically illegal to build under modern zoning codes and typically exist as non-conforming uses from pre-zoning eras. In Reading there are many of these types of housing in the areas directly surrounding downtown, almost all of them built pre-zoning.

Mixed Use: A building that combines multiple types of use, often referring to a building with commercial or office space on the first floor with residential units above, examples of which can be found in Reading’s downtown.


Aspects of zoning to consider in relation to number of units:

  • Number of parking spaces to require per unit
  • Dimensional standards of proposed buildings
  • Minimum lot size requirements
  • Setbacks from the street and lot perimeter


Affordability vs. affordability 

A lot of the discussion around housing centers on discussions of affordability. We think it is important to distinguish between legally defined capital “A” Affordable housing vs. the general discussion of affordability. 

Affordable housing refers to deed-restricted units that are only available to people who are at specific Area Median Incomes (AMIs). The AMI determines eligibility for Affordable housing and is set at a regional level by the US Department of Housing and Urban Development. Newly built affordable units are often available, for example, to those whose income is 80% of the AMI, though deeper affordability restrictions are possible (i.e. 50% AMI restrictions). 

Inclusionary Zoning refers to zoning that requires Affordable units to be included in newly built multi-family housing. Reading’s Downtown Smart Growth District (DSGD) currently requires Affordable units be provided in projects of more than 8 units.   

General affordability discussions on the lack of affordable housing options typically use the 30% of income spent on housing as a proxy to discuss affordability. While 30% of income is considered a general guideline for a max to spend on housing, this is not a legal definition. Affordability can mean different things to different people based on their circumstances. When we discuss or use the term affordable in our materials we mean a rental price or home price that would be consistent with median incomes.  

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1. What is MBTA Communities?
2. What does this mean for Reading specifically?
3. How did the state calculate our requirements?
4. Do we currently comply with the law?
5. Why should we comply?
6. What is the timeline for compliance?
7. Where are we in the process?
8. What do we know right now about our path forward?
9. What happens after the new zoning is adopted by Town Meeting?
10. General Zoning Considerations & Definitions
11. Helpful Studies and Links
12. Local Data, Resources, and Documents