ADU reform: Reshaping residential development landscape in Mass.? – by Anthony Susi – NEREJ

Report on the Impact of Massachusetts’ Accessory Dwelling Unit Legislation on Sustainable Development Goals

Introduction and Legislative Context

In 2024, the Commonwealth of Massachusetts enacted the Affordable Homes Act, a legislative measure designed to address housing shortages. A key provision of this act legalized the construction of Accessory Dwelling Units (ADUs) “by-right” across the state, with the exception of the City of Boston. This report analyzes the provision’s alignment with and contribution to the United Nations Sustainable Development Goals (SDGs), particularly those concerning housing, economic stability, and sustainable communities.

The legislation permits homeowners in single-family zoning districts to construct one ADU up to 900 square feet on their property without requiring special permits or extensive zoning reviews. This policy directly targets the expansion of flexible and affordable housing options.

Contribution to SDG 11: Sustainable Cities and Communities

The ADU provision is a direct mechanism for advancing SDG 11, which aims to make cities and human settlements inclusive, safe, resilient, and sustainable.

• Target 11.1 (Affordable Housing): The primary impact is on increasing the supply of adequate and affordable housing. ADUs, often referred to as in-law apartments or backyard cottages, provide smaller, less expensive residential options within established neighborhoods.
• Target 11.3 (Sustainable Urbanization): By promoting gentle density, the policy enhances sustainable urbanization. It allows for an increase in housing units without altering the fundamental character of existing communities or requiring large-scale, resource-intensive development projects.

Socio-Economic Impacts and Alignment with Additional SDGs

The legislation’s effects extend beyond housing to support broader socio-economic development goals.

1. SDG 1 (No Poverty) & SDG 8 (Decent Work and Economic Growth): The provision empowers homeowners by creating opportunities for supplemental rental income, contributing to household economic stability. Furthermore, the design, construction, and management of new ADUs stimulate local economic activity and create jobs.
2. SDG 10 (Reduced Inequalities): By increasing the availability of lower-cost housing, the policy helps mitigate housing inequality. It provides viable living solutions for various demographics, including seniors, single persons, and individuals with disabilities, who may be priced out of conventional markets.
3. SDG 3 (Good Health and Well-being): ADUs facilitate multi-generational living and aging-in-place. This allows families to provide care for relatives on-site, which can be a less expensive and more supportive alternative to institutional senior housing, thereby promoting well-being.

Implementation and Initial Outcomes

The “by-right” provision officially took effect in February 2025. Early data indicates significant uptake and progress toward achieving its housing objectives. While the streamlined process removes zoning hurdles, all ADUs must still adhere to local building codes and fire safety requirements.

• Communities with Filings: 170
• Applications Filed (First Six Months of 2025): 844
• Estimated Approvals (as of July 2025): 550

Conclusion and Future Outlook

The statewide legalization of ADUs in Massachusetts represents a pivotal shift in housing policy that strongly aligns with multiple Sustainable Development Goals. By simplifying the creation of small-scale, affordable housing, the legislation directly supports SDG 11 while also providing economic and social benefits that advance SDGs 1, 3, 8, and 10. The high rate of early adoption suggests that ADUs are poised to become a cornerstone of the state’s strategy for creating sustainable, inclusive, and economically resilient communities. For the real estate and property management sectors, this presents new opportunities for portfolio diversification and development.

1. Which SDGs are addressed or connected to the issues highlighted in the article?

The article on Massachusetts’ Affordable Homes Act and the legalization of Accessory Dwelling Units (ADUs) primarily addresses the following Sustainable Development Goal:

• SDG 11: Sustainable Cities and Communities

  This is the most directly relevant SDG. The article focuses on a state-level policy change aimed at increasing the housing supply, promoting affordable housing options, and managing urban development in a way that benefits communities without drastically altering neighborhood character. The entire initiative to legalize ADUs “by-right” is a strategy for creating more sustainable and inclusive human settlements.

2. What specific targets under those SDGs can be identified based on the article’s content?

Based on the article’s focus, the following specific SDG target can be identified:

• Target 11.1: By 2030, ensure access for all to adequate, safe and affordable housing and basic services and upgrade slums.

  The article directly connects to this target. The “Affordable Homes Act” and its ADU provision are explicitly described as being “Aimed at expanding affordable housing across the state.” The text highlights that ADUs are a “key strategy at the state level to boost housing supply and address rising demand.” The law allows homeowners to “add rental units or create housing for family members or individuals with disabilities,” which directly contributes to ensuring access to adequate and affordable housing for various segments of the population.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Yes, the article provides specific quantitative data that can serve as indicators to measure progress towards Target 11.1.

• Implied Indicator: Number of new housing units created through ADU provisions.

  While not a formal UN indicator, the article provides direct data points that measure the implementation and success of the policy aimed at increasing housing supply. This data serves as a practical indicator of progress. The article states:

  • “in the first six months of 2025, homeowners in 170 communities filed 844 applications to build ADUs on their properties.”
  • “An estimated 550 of those applications have been approved as of July.”

  These figures directly quantify the increase in potential and approved housing units, which is a measure of progress toward providing more “adequate, safe and affordable housing.” The number of applications filed and the number of units approved are concrete metrics tracking the policy’s impact.

4. Table of SDGs, Targets, and Indicators

Source: nerej.com