Manchester requires a "Conditional Use" permit in order to build an ADU on the property of your single family home. The regulations for obtaining that permit can be found in the City of Manchester's Zoning Ordinance (Linked Here). The ADU regulations are found in section 8.26 titled "Accessory Dwelling Unit". Here are some quick points from the ordinance: only one ADU per single family property, a property with an ADU must have either the primary home or ADU occupied by the owner, ADU must be attached to the primary house (we will talk more about this in other posts), ADU can have no more than 2 bedrooms, the property must be able to accommodate the additional parking, ADU shall have adequate water and sewer connections, the ADU cannot have a front door facing the street, and the design of the ADU must result in a similar aesthetic to the primary house.

These are the basic rules for an ADU in Manchester but there is more nuance to the regulations than what is defined in section 8.26 of the Zoning Ordinance. In order to get a conditional use permit, you would need to obtain an approval via a hearing with the Planning Board. Gathering the required information and funds to obtain a hearing with the Planning Board can be a difficult and costly effort. The conditional use permit application (Linked Here) identifies the fees required for hearing notice and staff review administrative fee which will approximately cost $400 and can require thousands in documentation.

Article 12 of the Manchester Zoning ordinance (Linked Here) spells out the requirements for obtaining a hearing with the Planning Board for a conditional use permit. There are two different procedures for obtaining a hearing date with the planning board, one where a site plan approval is required and one where a site plan is not required. The type of ADU you wish to build will largely determine if you will need a site plan approval. If your single family residence in any way does not comply with the current underlying zoning and site plan regulations, the community development staff are going to require you seek a site plan approval. Additionally, even if you have a home that meet all of the regulations but you intend to build an addition to your home to accommodate the ADU, you then will likely find your plans will require a site plan approval. The nuance of when a survey and site plan are required are largely determined by staff ahead of any hearing with the Planning Board. Depending on the context of your property, you may be required by the Community Development staff to produce a site plan and survey of your property by a qualified engineer, this can cost between $3,000 and $6,000 or more in some circumstances.

This post is intended to provide a general understanding of the requirements to building an ADU. The context of approvals is different for every property and as an owner considering building an ADU, you will need to do research to determine which regulations will apply to your property and how those regulations will impact what type of ADU to choose to build. In the classes offered, we will take a deeper dive into some of the issues surrounding the ordinance language and talk about potential changes to the language which would create an easier path for homeowners to achieve their goals without reducing the safety property value the city regulations seek to uphold.

Regards,

James Vayo