Plus One ADU Program FAQs

What is an ADU?

Accessory Dwelling Units (ADUs) are secondary housing units on a single-family residential lot.

What is the Plus One ADU Program?

The Plus One ADU Program is an initiative to create and improve Accessory Dwelling Units (ADUs). The program is aimed at supporting low- and middle-income single-family homeowners who wish to

  • Build a new ADU within their home
    • In the Towns of Shelter Island and Southampton, homeowners can also locate ADU’sin detached accessory structures
  • Improve an existing ADU that needs to be brought into compliance with local requirements

I’d like to build an ADU – am I eligible for the Plus One ADU Program?

Do you live full-time in the home you own in the Towns of Babylon, Shelter Island, or Southampton? Does your annual income fall within the below guidelines? Yes, you are!

I have an existing ADU that I would like to legalize – am I eligible for the Plus One ADU Program?

Yes! If (1) you are a full-time homeowner occupant with annual income that meets the above requirements, and (2) The structure meets the Town’s zoning requirements.

How much funding am I eligible for?

The Plus One ADU Program may provide up to $125,000 (which includes CDCLI program support, such as design, permitting, construction oversight, closeout and ongoing compliance)in forgivable grant funds, for low- and middle-income homeowners.

What if constructing my ADU costs more than the grant can provide?

Either (1) Reduce project scope to be within budget, or (2) Submit proof that you have or can borrow the necessary additional funds to complete the project (Homeowners can inquire about CDCLI’s Community Development Financial Institution’s loan products).

Is the Plus One ADU Program a loan program? Do I have to pay the money back?

The Plus One ADU Program is a forgivable grant program. As long as you continue to meet program requirements, you will not have to pay the money back. Homeowners and ADU renters must maintain year-round residency and keep property in good condition and repair for 10 years or until sale of property. A deed covenant will be required to be filed with the County Clerk.

I’d like to be a designer/builder/contractor– how can I partner with CDCLI to build ADUs?

That’s great! Contact us here: 631-364-5646 or email us at:


Application FAQs

What do I need to complete an application?

Proof of ownership, residency, and income. See our Required Documents PDF for all the required

What happens once my application is submitted?

You will receive confirmation that your application has been received. Applications will be reviewed for completeness. You may hear from us regarding additional documentation/information. Once your application is complete, you will receive a notification letting you know if you have passed eligibility/preapproval.

When will applications be available & for how long?

The application portal is live CDCLI website here.

Who will manage my construction?

CDCLI will oversee all aspects of the construction process from contractor bidding & selection, compliance with MWBE/SDVOB utilization standards, general construction oversight & coordination between property owners and contractors, preparation of payment requests & other essential activities to ensure efficient construction.

I have a design professional/contractor in mind, can I work with them?

Yes, if they meet our requirements (licensing, insurance, etc.) and there is no conflict of interest. You may also be required to obtain additional written quotes to show that costs are competitive.

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