Accessory Dwelling Unit Application Instructions

These instructions are provided to assist you in making an application for an Accessory Dwelling Unit (ADU), which is described in Section 10.814 – Accessory Dwelling Units of the Zoning Ordinance.

  1. Confer with Planning and Sustainability Staff: Meet with staff informally to discuss your potential ADU, explore options and to identify any concerns prior to making an application.
  2. Establish An Account in the City's Online Permitting Portal:  In order to file an application for an ADU, you need to establish an account. When you register for the first time, you’ll need to access your email account in order to activate your account. The person completing the online application should be the primary point of contact for the project. If not the owner of the property, an authorization from the property owner must be provided. All automatic notifications on the application’s status, approvals, and staff comments will be sent to the email address of the primary point of contact.

  3. Complete a Building Permit Application: Complete the online building permit application and pay the required permit fee. Be sure to upload all supporting documents, plans, and exhibits. Permit fees can be found on the Inspections Department Building Permit Fees Page. 

    If the project will need land use approvals, Planning Department staff will flag the permit in the online permitting portal and a notification will be sent to the applicant outlining the appropriate land use approval process.

  4. Ensure Completeness: Planning and Inspections Department staff reserve the right to refuse applications that do not meet the minimum requirements.  Additional information and/or exhibits that illustrate the scope of the project may be requested by staff. It is the obligation of the applicant to submit adequate plans and exhibits to demonstrate compliance with the Zoning Ordinance. The applicant may use the City's online mapping program MapGeo and/or Assessor Data to help them provide additional information for their permit application. 

The Applicant is encouraged to consider the following when completing the application:

  • Provide neat and clearly legible materials. 
  • Use of color or highlights is encouraged in order to identify pertinent areas on submitted plans
  • Applicants are encouraged to review the application with a member of the Planning Department staff prior to submittal.
  • All applicants are encouraged to discuss the project with neighbors. 

For additional information on application requirements and the land use approval process, please refer to the City of Portsmouth Zoning Ordinance and the Planning Board Rules and Regulations or contact the Planning and Sustainability Department directly at (603) 610-7216.