Mayor Mamdani Unveils New Tools and Financing to Help Homeowners Add Ancillary Dwelling Units

NEW YORK – Today, Mayor Zohran Kwame Mamdani unveiled a new set of tools to make it easier for homeowners to stay in their communities and bring in extra income by adding an ancillary dwelling unit (ADU) to their property. The city’s new ADU for You website features an ADU Guidebook, a growing Pre-Approved Plan Library, and site feasibility analysis and cost estimating tools to help homeowners navigate bureaucratic and financing details when adding an ADU such as a backyard cottage or “in-law unit.”

The City will also newly reopen applications for the Plus One ADU program, which offers financial and technical assistance to qualified homeowners to add an ADU. The Plus One ADU program, established with City funding and grants provided by the New York State Homes and Community Renewal, and operated in partnership Restored Homes HDFC, provides homeowners with up to $395,000 in financial support and technical assistance to add an ADU. The program saw overwhelming interest from New Yorkers when it first launched, receiving over 1,300 submissions within two weeks, but has been closed to new applicants since February 2024.

“One of the solutions to the housing crisis can be found in our backyards, our attics, or our basements – in an Ancillary Dwelling Unit. That's why our administration is making it easier and more affordable to build an ADU through a library of pre-approved plans and new financing options,” said Mayor Mamdani. “By making it easier for New Yorkers to turn their homes into an extra place for a loved one or a little more income, we're allowing our city to grow while keeping the character of the neighborhoods we love.”

“In the midst of a dire housing crisis, ADUs are an important tool for homeowners to add space, bring in extra income, and stay in their communities - but creating an ADU can feel out of reach for too many New Yorkers. These new tools will help ensure that any New Yorker who wants to add an ADU is able to do,” said Leila Bozorg, Deputy Mayor for Housing and Planning. “Whether you are interested in adding a new backyard cottage or converting an underused garage or attic into housing, we have resources to help guide you through the process.”

“Ancillary dwelling units have the potential of unlock thousands of safe, quality homes for New Yorkers in low density neighborhoods across the city,” said Buildings Commissioner Ahmed Tigani. “However, these homes will not get built if the permitting process places too many barriers in the way. Today's announcement includes multiple tools that will help remove these barriers, including the new Pre-Approved Plan Library which gives New Yorkers a menu of potential design options that have already undergone an initial review by DOB for code-compliance leading to faster approvals.”

“By making it easier to navigate rules and offering pre-approved designs, this new homeowner toolkit will help New Yorkers turn the idea of an accessory dwelling unit into a reality,” said Sideya Sherman, Director of the Department of City Planning. “Building on City of Yes for Housing Opportunity, this is another smart step to unlock housing, allow working families to earn additional income, and help seniors afford to age in place.”

“New York City needs more housing. Some of it is going to come from backyards and basements — and that is not a small thing. ADU for You makes it possible for homeowners who want to be part of the solution to actually do it, giving New Yorkers the plans, the financing, and a clear path forward,” said Dina Levy, Housing Preservation and Development (HPD) Commissioner.

Thanks to City of Yes for Housing Opportunity and subsequent regulatory changes, one- and two-family homeowners in much of the city can add an ADU to their properties – a change that will help add housing options in low-density areas while maintaining the existing character.

In addition to helping homeowners understand the regulations and access financing to build an ADU, the Mamdani administration is also launching a simplified permitting process for pre-approved ADU plans. This pre-approved plan library is launching with eleven ADU designs that have already been reviewed and approved by the Department of Buildings (DOB). The city will connect homeowners who select an ADU option from this library with the registered design professional who created the design in order to obtain site-specific approval. DOB will review and add additional pre-approved plans as they are submitted by design professionals.

“Governor Hochul’s Plus One ADU Program is increasing housing supply and providing an extra source of income for homeowners in New York City and across the state. The $85 million program was launched in 2023 with the city of New York and six other partners - the program has since grown and we currently have 14 partners working to create more than 550 ADUs throughout the state. HCR is looking forward to seeing all 37 projects in New York City completed, and we are confident these projects will have a transformative effect on the City’s housing landscape,” said RuthAnne Visnauskas, Commissioner, New York State Homes and Community Renewal.

“WXY was proud to lead the City’s innovative effort to move accessory dwelling units forward in New York. ADUs can create new opportunities for homeowners to age in place, generate rental income, and make space for family, all while adding new housing in a way that enables gentle growth and helps keep the overall character of neighborhoods intact. That balance is the type of housing model that more cities should be looking to implement, and I’m excited to see New York City lead the way,” said Adam Lubinsky, Principal, WXY Architecture + Urban Design.

“Ancillary dwelling units, or ADUs, serve a dual purpose of increasing the stock of quality, affordable housing while providing supplemental income to homeowners seeking to remain in their homes and communities.” said Salvatore D’Avola, CEO, Restored Homes Housing Development Fund Corporation. “The new tools and resources being made available to the public through the “ADU for You” program will provide critical guidance and information for homeowners interested in adding an ADU. We continue to be proud of our participation in the City’s efforts to promote ADUs and are ready to respond to inquiries through our Resource Center.”

“Accessory Dwelling Units are a smart way to expand housing while supporting the homeowners who anchor our neighborhoods. Programs like ADU for You make it easier to safely convert existing space into legal homes—creating new housing, helping families generate income, and allowing more New Yorkers to age in place. Habitat for Humanity New York City and Westchester County is proud to help homeowners navigate the process and be part of the solution to our housing shortage,” said Sabrina Lippman, CEO, Habitat for Humanity New York City & Westchester County.

“New Yorkers want the ability to grow older in the neighborhoods where they raised their families and built their lives,” said Beth Finkel, State Director, AARP New York. “We thank Mayor Mamdani for advancing tools that make it easier for homeowners to create accessory dwelling units. ADUs can help older homeowners remain in their communities by providing additional income that helps them afford to stay in their homes, while also making it easier and more affordable for family caregivers to live nearby. Expanding these options is an important step toward helping more New Yorkers age in place with dignity, independence, and the support they need.”

“New York City doesn’t just need more housing — it needs more kinds of housing, at a wider range of price points,” said Howard Slatkin, Executive Director, Citizens Housing and Planning Council. “CHPC’s polling of low-density neighborhood residents found that they struggle to find housing within their communities, and that rental units are particularly important to homeowners of color. ADUs help fill in gaps in our housing stock, to the benefit of both renters and homeowners. Measures like the pre-approved ADU plan library are important to bring these opportunities within reach of a more diverse range of homeowners.”

“This initiative is an important step toward making accessory dwelling units a more affordable and viable option for homeowners across New York City,” said Christie Peale, CEO and Executive Director, Center for NYC Neighborhoods. “By making ADU development more accessible, the City is giving homeowners a tangible opportunity to generate income, continue building intergenerational wealth, keep their families together, and stay in their communities. We commend the City for this commitment and look forward to seeing these tools reach the neighborhoods that need them most.”

“The City took a big step last year when it allowed more creation of Accessory Dwelling Units. Now we need to make it easy and inexpensive to actually construct one. The Plus One ADU program does just that, helping homeowners create more housing options throughout parts of the Five Boroughs where they have often been hard to find,” said Moses Gates, Vice President of Housing & Neighborhood Planning, Regional Plan Association.

“New Yorkers overwhelmingly agree we need to build more homes. City of Yes for Housing Opportunity began turning that broad consensus into policy—ADU for You puts that policy into action, helping homeowners and renters alike manage rising housing costs while adding homes in the neighborhoods of greatest need. A cottage for an aging parent. A first apartment for an adult child just starting out. A dedicated space for a caretaker or extended family. ADUs can help meet the housing needs of New York families of all cultures, life stages, and sizes. We are thrilled to see the Mamdani administration seizing this momentum to support more housing options for New Yorkers,” said Annemarie Gray, Executive Director, Open New York.

“We applaud Mayor Mamdani and his administration for expanding housing options for New Yorkers through ADUs,” said Rachel Fee, Executive Director, New York Housing Conference. “ADUs will provide affordable, flexible living arrangements for intergenerational families, seniors and caregivers across the five boroughs. We are excited to see the administration build on City of Yes for Housing Opportunity by offering tools that provide clear guidance and financial support so more New Yorkers can access and benefit from more housing.”

“ADU for You serves as a one-stop shop for homeowners, providing critical information to enable New Yorkers to take full advantage of the tools unlocked by City of Yes for Housing Opportunity,” said Jesse Lazar, Executive Director, American Institute of Architects New York (AIANY). “The collection of pre-approved ADU designs showcases the opportunity to build various types of quality ADUs at different price points, utilizing a range of materials and creative design solutions that meet the unique needs of the homeowner.”

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