Accessory Dwelling Units

1. Overview

What are Accessory Dwelling Units?

Accessory Dwelling Units (ADUs) are commonly known as:

  • garage apartments
  • granny flats
  • in-law suites

ADUs are self-contained residential units on the same property as a single-family home, as long as the property meets zoning requirements. ADUs can be:

  • attached to the main dwelling unit
  • detached and be a separate unit
  • a converted garage or above the garage
  • fully separated units within the main dwelling unit

Other requirements include:

  • kitchen (or efficiency kitchen)
    • separate units without a permitted kitchen will be classified as an addition, not an ADU 
  • bathroom
  • place to sleep
  • separate entrance from the main property
  • only one (1) ADU is allowed per lot

Why have an Accessory Dwelling Unit?

ADUs provide the following benefits:

  • earn extra income from renting to a tenant
  • provide a home for a relative in need of care 
  • provide housing for relatives or friends 
  • space for guests
  • living quarters for on-site caregivers
  • increase home value

The early design stage is a good time to consider how you might use your ADU in the future. In some cases, how you use your ADU may change based on your needs. For example, you might be building the ADU for rental income today, but it might become a residence for a parent in the future. If your ADU might become a home for someone with mobility challenges in the future, it is typically more economical to incorporate aging in place or universal design standards in the original building design.

2. Find out if you're eligible for an ADU

To find your eligibility, you can look up your property to ensure it's in the city limits and what are its zoning categories.

  1. Use the Orlando Information Locator to find your property's information
  2. After entering your address, on the left-hand side menu look at the first box that says "Jurisdiction," if it says "City of Orlando," you're good to continue
  3. Scroll down the left-hand side menu and click on the "Zoning" box to view the information

If your zoning category starts with R-1, R-2, R-3, MXD, O-1, O-2 or PD, you may be eligible for an ADU, depending on your lot size.

Your property must also meet additional standards, which can be found in the city code. 


3. Lot size requirements and allowable ADU size

Minimum ADU size

The minimum size of your unit depends on the number of people who will live in the ADU. The City of Orlando code does not have a minimum allowable size for ADUs, but does require your lot to be a certain size to meet eligibility. If you are proposing an ADU less than 300 square feet, please review the minimum code standards. See Section 404 of the International Property Maintenance Code for details.

Maximum ADU size

There are two steps to determine the maximum size of your ADU and whether you meet the minimum lot size requirements to be eligible for an ADU. 

Step 1: Check your zoning category's minimum lot size requirement

Your property may be zoned to allow an accessory dwelling unit depending on the zone's minimum lot size requirements. Check the table below to see if your lot meets its zone's minimum lot size.

Reminder, you can use the Orlando Information Locator to determine your zoning category, which corresponds with the categories below

 Zoning Minimum lot size for an ADU
up to 500 sq. ft. * ✝
Minimum lot size for an ADU
up to 1,000 sq. ft. * 
R-1AA  10,000 15,000
R-1A 7,700 11,550
R-1 6,000 9,000
R-1N 5,500 8,250
R-2A 5,500 **
R-2B 5,000 **
R-3A 5,500 **
R-3B  5,000  **
R-3C  4,500 **
R-3D 4,500 **
MXD-1 5,000 **
MXD-2 4,500 **
O-1 5,500 **
O-2 4,500 **

* All accessory dwelling units must be smaller than the main dwelling. If the lot does not meet the minimum size, check with City Planning staff to see if it is a “legally non-conforming lot of record.” If so, it may be eligible for a variance to allow an ADU.

✝ Historic District: If your property is located within a Historic District (Historic Preservation), your maximum ADU size is 700 square feet. You will need to go through the Major Review process to apply for a Certificate of Appropriateness with the Historic Preservation Board before applying for building permits. 

** Must comply with city Tandem Code - Part 3C of Chapter 58.

Planned Development (PD)

If your property is zoned PD, please contact the Planning Division to find out if an ADU is permitted on your property.

Southeast sector

All residential properties located within the Lake Nona PD are eligible for one (1), 1,000 square foot ADU, regardless of the lot size.

Step 2: Floor Area Ration (FAR)

The maximum square footage of the house plus the ADU must not exceed 50% of the total square footage of the lot (0.50 FAR). This may further limit the maximum size of the ADU.

Example for a 2,300 square-foot house in a R-2A, 5,500 square-foot lot:

  • FAR: 5,500 x 0.5 = 2,750 square feet maximum remaining 
  • If the house is 2,300 square feet, the maximum remaining area is 450 square feet (2,750 - 2300), so that is the maximum ADU size

ADUs in the Lake Nona PD are not limited to FAR standards, but they must comply with the Planning Standards.

4. Planning Standards

In addition to the zoning and lot size, there are additional standards that your property must meet to know if an ADU is possible on your property. Overall standards are provided in Chapter 58, Part 3A.

Location on the lot

  • May be attached to the main house, detached in a separate building or attached to a garage
  • If detached, may not be in front of the main house
  • Must meet zoning district setbacks (see below)


Setbacks are the minimum required distance between the property lines and a structure.


Impervious Surface Ratio (ISR)

Impervious surfaces are surfaces that let little to no water seep through into the ground. The Impervious Surface Ratio is the maximum amount of impervious surfaces allowed on a lot (how much can be paved versus how much needs to be grass for water absorption). Buildings, concrete, asphalt, pavers and artificial turf are all considered impervious surfaces.

Each zoning district limits the amount of impervious surface on a lot. Check the tables shown in Chapter 58, Part 1B to find your district’s limit. 

Impervious Surface Ratio = Impervious Surface Area / Lot Area.

Distance from waterbodies

If you own a property that abuts a body of water, a surveyor must provide a survey that includes that body of water’s average water line.

Detached ADUs must be located at minimum 15 feet from the normal high-water elevation or wetland boundary and have a maximum height of 12 feet. Attached ADUs must meet the principal structure setback of 50 feet.


  • The ADU must have the same exterior finish as the main house and must include similar architectural details. This will be reviewed as part of the building permit application. Alternative design may be requested via an Appearance Review Determination before applying for building permits.
  • If your ADU is located on a corner lot, an Appearance Review Determination is required before building permits. Email City Planning staff for details:

5. Building Standards

Minimum building standards are in Chapter 14, Sections 14.10 and 14.11 of the City Code and are also found in the Florida Building Code.

Type of structure

  • An ADU must be located in a permanent structure built on a permanent foundation and must meet all relevant residential building code requirements
  • Any structure that meets the city’s definition of a recreational vehicle or a mobile home may not be used as an ADU


  • Must include a kitchen sink with hot and cold running water, food preparation surfaces, food storage areas (shelves, cabinets and/or drawers), stove (portable equipment such as a microwave or hot plate are not sufficient), and refrigerator


  • Must include a sink and tub or shower with hot and cold running water
  • A toilet with running water
  • The room must be at least 30 square feet and include appropriate accessories (towel rod, etc.)
  • Must have mechanical ventilation or an operable window

Heat and air conditioning

  • The ADU must have heating
  • Air conditioning is not required. However, if air conditioning is not provided, windows must be operable and screened to allow proper ventilation


  • The ADU must be connected to the electric utility network 
  • Solar power may be used as a secondary supply only

Water supply

  • If the main house has a public potable water connection and is served by a public utility, the ADU must be connected to the public utility service
  • If the main house has well water, please work with your contractor to determine which health codes apply. It is possible you will be required to connect to a public potable water supply  

Sanitary sewer (wastewater)

  • If the main house has a sanitary sewer connection and is served by a public utility, the ADU must be connected to the public utility service
  • If the main house is on a septic system, please work with your contractor to determine which health codes apply. It is possible you will be required to connect to public utilities or replace the septic tank
  • A properly permitted gray water system may be used only as a secondary option



6. Ownership and Impact Fees


  • The main house may be owner-occupied or rented to a long-term tenant
  • The ADU may be owner-occupied or rented to a long-term tenant
  • If you would like to do short-term rental or home sharing, special rules apply, and is not allowed in all situations
  • The same person or entity (business, trust, etc.) must own both the main house and the ADU. The ADU cannot be sold to a separate owner
  • The lot that the main house and the ADU are located can be split into two separate lots, if the future/resulting lots meet Tandem Single Family Development, Section 58.516

Impact Fees

  • ADUs are subject to transportation and park impact fees. Sewer benefit fees, electric connection fees and water connection fees may also be required
  • ADUs are exempt from school impact fees
  • Impact fee rates can be found on the Permit Development and Impact Fees page. ADUs are classified as “multifamily”
  • If a single-family home already exists on the lot, the lot will get a credit for one single family home, and impact fees will be charged for two multifamily units. This net increase is less than the stand-alone rate
  • On a vacant lot where a new single-family home and an ADU are being built at the same time, impact fees will be charged for two multifamily units


Please refer to our Impact Fees page.

Or contact Nancy Ottini, Impact Fee Manager


Phone: 407.246.3529


7. Permitting Process

The City of Orlando’s Permitting Services is responsible for overseeing residential and commercial permits.

Figure out what permits you need

To determine which specific permits you will need to apply for, you can use our Digital Permitting Portal which will walk you through the process, step-by-step. This portal guides users through a series of questions about their ADU project and preliminarily identifies and calculates permit costs for your project. To begin, go to the guide and click on "Residential Portal."

For best results, gather the following information before starting:

  • General project information
  • Site improvements
  • Anticipated electrical upgrades
  • Plumbing fixtures
  • Cost estimates for such improvements

You will be able to download and/or save this project on the portal. 

Visit the Digital Permitting Portal

Other information for permits and inspections


Contact Permitting Services


Phone: 407.246.2271

8. Universal Design

It is important to consider whether the ADU will be used now – or potentially in the future – as a residence for a family member who has mobility challenges or an aging parent. Individuals with mobility or chronic illnesses may need help with “activities of daily living” such as bathing or dressing – or – “instrumental activities of daily living” such as managing medications or meal preparation.  Incorporating “aging in place” or “universal design standards” in the original building design is typically more economical than retrofitting these features into an ADU at a later date.

Universal Design features

Universal design features focus on making homes and environments safe, navigable and comfortable for people of all ages and abilities.  A search for “home-fit guide” or “universal design” or “aging in place features” will provide an overview of common universal design features, such as:

  • Zero-entry door (no steps to house)
  • Zero-entry shower
  • Non-slip flooring
  • Levered handles on doors and faucets
  • Light switches that are accessible from a wheelchair
  • Good lighting

9. Do Your Research

Before getting started with your own ADU, we recommend you conduct your own research to get familiar with the ADU concept and how they are designed and built. Several research steps that may be beneficial are listed below. You are also encouraged to add or modify these steps to fit your needs.

Get basic information

There is a wealth of information about ADUs on the internet. The nonprofit website has helpful links to articles, guides, checklists, videos and photo albums about building ADUs. A web search for "ABCs of ADUs" can also provide an overview of what ADUs are and how ADUs expand housing options for people of all ages.  

Review basic floor plans

The internet has plenty of great ADU examples. Some construction companies specialize in ADUs, and many cities throughout the country have adopted “pre-approved” ADU building plans that meet their own city codes and permitting processes. While these plans don't necessarily meet the City of Orlando standards, they can provide visuals and examples of different floor plans, types of ADUs and architecture. An internet search for “cities with pre-approved ADU plans” is a good start to learn more. You can also search for “ADU floor plan”, “ADU 500 square feet” or even “ADU ideas” for inspiration.

Consider visiting local furniture stores

Look for opportunities to see how professionals stage small apartments and spaces. One place to visit is local furniture stores that often have “room displays” that depict how their furniture can be configured in smaller spaces. 

10. Discover More About ADUs

Benefits of supportive housing for a family member 

ADUs are a solution to families who wish to care for their aging parents or relatives with physical or cognitive health issues. This proximity to family provides caregivers with a sense of security and the ability to provide accessible care, while at the same time providing a sense of independence for the family member. This multigenerational approach may replace or delay the need for more structured assistive residential options such as assisted living or skilled nursing facility.  

Emotional benefits

  • Separate living space
  • Quality of life / sense of independence
  • Sense of security

Health benefits

  • Physical activity
  • Mental health
  • Access to health care

Social benefits

  • Close to family / social interaction
  • Intergenerational relationships

Financial considerations

Families that are considering building an ADU to provide supportive housing for a family member that can no longer live safely alone, should conduct a “cost analysis” that compares the cost of building an ADU with the cost of an assisted living or nursing home. Considerations should include ADU construction costs, on-going ADU costs such as homeowners insurance and increase in property maintenance, and the reoccurring cost of either an assisted living facility or nursing home.  

ADU costs to consider 

  • Construction costs (one-time allocations) – Each ADU has different line-item costs that will vary based on the property characteristics, type of ADU being constructed and more. However, an internet search for “complete ADU development cost breakdown” can provide a list of typical items that should be factored into your cost estimates for building an ADU. 
    • ADU design and planning costs (i.e., architectural drawings, engineering calculations, energy calculations, land surveys)
    • City fees association with construction (i.e., plan reviews, utility fees, building fees and impact fees)
    • Labor and material costs (for interior and exterior)
    • Appliances and furniture costs
    • Landscaping costs
  • On-going costs
    • Property taxes
    • Homeowners insurance
    • Utility costs
    • Maintenance costs

Average costs for other residential care options 

  • An internet search for “annual cost of care survey” should provide an estimate for reoccurring costs associated with an assisted living facility or skilled nursing facility. Note: Some care comparisons for assisted living facilities may not factor in costs associated with higher levels of care
  • Annual cost of a skilled nursing home or assisted living facility
  • Additional level of care costs

11. Contact Us


Questions for maximum ADU size, setbacks, site standards, lot splits and appearance review, etc.

Planner on Call
Phone: 407.246.2269


Questions about structures and materials, interior requirements and ADA compliance, etc.

Permitting Services
Phone: 407.246.2271

Permitting and Inspections

Questions for costs, permit reviews, and what type of permits you must apply for, etc.

Permitting Services
Phone: 407.246.2271

Impact Fees

Nancy Ottini, Impact Fee Manager
Phone: 407.246.3529