Can You Add An ADU In New Carlisle? What The Code Says

Thinking about adding a backyard cottage or converting your garage in New Carlisle? You are not alone. An accessory dwelling unit can create space for family, future flexibility, or rental income. In this guide, you will learn what the town code actually says, what it does not say, and the steps to take before you start design or construction. Let’s dive in.

Quick answer for New Carlisle

New Carlisle’s code defines a “dwelling, accessory” as a dwelling unit that is subordinate to a single-family home. The town allows accessory uses and buildings in Residential Districts, but it does not have a stand-alone ADU ordinance with detailed, ADU-only rules. In practice, your ADU will be reviewed under the accessory building and district standards, and some second-dwelling situations can require a special exception. Start by reading the town’s definitions and accessory use language, then confirm with staff before you assume your plan is permitted by-right.

• Read the town’s definition of “dwelling, accessory” in the code’s definitions section. See the definition in the town code.
• Accessory uses and buildings in Residential Districts must follow district standards unless a specific exception exists. Review accessory use standards.

ADU types that can fit

Attached or internal conversion

If you plan to convert space inside the main home, such as a basement or attic, or add an attached suite, you will still need building permits and must meet residential building code. Conversions inside the primary dwelling generally avoid the “one detached accessory building” limit, but they are still treated as accessory use and must satisfy the district’s development standards. Confirm setbacks, parking on site, and any utility needs with the Town before design goes too far.

Detached cottage or garage conversion

A detached ADU can be possible, but there are two important controls you need to meet:

• Only one detached accessory building is allowed per lot, not counting small sheds under 120 square feet. If you already have a detached garage, ask how that will be counted if you propose a new cottage or a garage conversion.
• The total square footage of any detached accessory building must be less than the main floor area of your primary dwelling. That ratio often sets the maximum size of a backyard cottage.

Both rules are in the town’s accessory building standards. Read the accessory building provisions. You must also honor setbacks, lot coverage, and avoid encroaching on easements.

Key rules that shape your ADU

• One detached accessory building per lot. Storage sheds under 120 square feet do not count toward this total.
• Detached building size must be smaller than the main floor area of the house.
• All accessory buildings must meet your zoning district’s setbacks, height, and lot coverage.
• No encroachment on recorded easements without consent.
• Some second-dwelling situations tied to caregiver or care-receiver relationships may require a special exception from the Board of Zoning Appeals.

You can find these standards in the town’s code for accessory uses and the definitions section. Start with the residential accessory use rules and the definitions.

Permits, utilities, and inspections

Building permits and code compliance

Creating a second dwelling unit triggers permits and inspections. The Town’s Building Department can tell you which plans to submit and the inspection schedule. Indiana enforces the Indiana Residential Code for one- and two-family dwellings, so expect requirements for egress, smoke and CO alarms, fire separation, and mechanical, electrical, and plumbing systems.

• Contact the Town’s Building Department for permits and plan review steps. Visit the Building Department page.
• See the current state residential code context used by inspectors. Review Indiana Residential Code adoption.

Sewer vs septic

If your home is on municipal sewer, a new unit can add demand and may involve connection or system development fees. If the property is on a private septic system, adding bedrooms or a second kitchen often triggers a septic review, upgrade, or replacement. The St. Joseph County Health Department handles septic permits and requires a soil report from a certified soil scientist for new or modified systems.

• Learn about septic permits and soil report requirements. See the county’s septic guidance.
• For utility fees and system development charges on sewer connections, review the town’s rates section and call Town Utilities to confirm current charges. Read the utility rates and charges section.

Meters and billing

New Carlisle’s online code does not spell out a town-wide ADU policy on separate utility meters. Some cities require shared meters for ADUs while others allow separate service. Ask Town Utilities if separate water or electric meters are allowed or required for an accessory dwelling on your parcel.

When you need BZA approval

Most projects that meet the district and accessory standards proceed with building permits. If your design needs relief from a setback, height, lot coverage, or the one-detached-building rule, you will likely need a variance. If your situation fits the code’s caregiver or care-receiver dwelling category, you may need a special exception. The Board of Zoning Appeals hears both types and applies specific decision criteria.

• Review the BZA’s authority and procedures. See the BZA section of the code.

Step-by-step plan to move forward

• Identify your zoning district and read its development standards. If you cannot find the zoning map online, call the Town to confirm. Start at the Town’s website.
• Choose your ADU format: internal conversion, attached addition, or detached cottage or garage conversion.
• If detached, measure your home’s main floor area and confirm your design is smaller. Also check whether you already have a detached accessory building.
• Check setbacks, lot coverage, and any recorded easements on your site plan.
• Decide if you need a variance or special exception. If so, get the BZA filing checklist and timeline.
• Prepare plans with structural and MEP details, then apply for building permits. Use the Town’s Building Department page.
• Confirm utilities: sewer availability, any tap or system development charges, and meter policy. Review the utility rates section.
• If on septic, order a soil report and apply for a county septic permit. Follow county septic steps.
• Schedule inspections and secure a certificate of occupancy after final approval.

What the code does not spell out

Because New Carlisle does not publish a stand-alone ADU ordinance online, several common questions do not have explicit answers in the code text. These include owner-occupancy requirements, on-site parking minimums for an ADU, short-term rental rules, and meter policies. The safest move is to get written guidance from the Building Department or Planning staff before you finalize plans. You can then align your design with the town’s interpretations and avoid surprises during review.

A local partner for your ADU goals

Adding an ADU can support family needs today and boost resale value tomorrow. If you are weighing a conversion or a backyard cottage as part of your buying or selling strategy, you do not have to map it out alone. With local new-construction insight and community knowledge, I can help you evaluate feasibility, connect with the right town contacts, and position your next move with confidence. Reach out to Meghan Maddox to talk through your plans and next steps.

FAQs

Are ADUs allowed in New Carlisle residential zones?

• Accessory dwellings are treated under the town’s accessory use standards for Residential Districts, so they are possible if you meet district rules and accessory building limits. Check the residential accessory use section.

How big can a detached ADU be in New Carlisle?

• A detached accessory building must be smaller than the main floor area of your primary dwelling, and you are limited to one detached accessory building per lot. See the accessory building limits.

Do I need a special exception for a caregiver unit?

• The code defines caregiver and care-receiver dwellings and treats them as special exceptions, which require Board of Zoning Appeals review. Review the definitions and BZA process.

What permits are required to create an ADU in New Carlisle?

• You will need building permits and inspections through the Town’s Building Department, and your plans must meet the Indiana Residential Code. Visit the Building Department and see Indiana’s code context.

How do sewer or septic rules affect an ADU?

• Municipal sewer connections can involve tap or system development fees, and septic properties require county review with a soil report for new or modified systems. Review town utility charges and county septic requirements.