Accessory Dwelling Units in Brevard County, FL: What the Code Actually Allows

Can you build an accessory dwelling unit in Brevard County, Florida?

Yes, but in unincorporated Brevard County an accessory dwelling unit is a conditional use, which means a permit hearing rather than an over-the-counter approval. The City of Melbourne allows them by design standard on lots of at least 14,520 square feet.

This comes up constantly with relocation buyers. Parents are moving down from the Northeast within a year or two, adult kids want a landing spot, or someone wants a private suite for the six weeks of winter visitors. The instinct is to find a house with room to add a small second unit out back.

On the Space Coast, whether that works depends almost entirely on which line on the map your property falls on. A parcel in Suntree or on Merritt Island is unincorporated and answers to Brevard County code. A parcel inside Melbourne city limits answers to a completely different and noticeably friendlier set of standards. Here is what each one actually says.

Does Florida require cities to allow ADUs?

No. Florida Statute 163.31771 says a local government "may adopt an ordinance to allow accessory dwelling units in any area zoned for single-family residential use." Permissive, not mandatory. The statute defines an ADU as an ancillary or secondary living unit with a separate kitchen, bathroom, and sleeping area, either inside the same structure or on the same lot as the primary dwelling. It also requires a permit applicant to submit an affidavit attesting the unit will be rented at an affordable rate to lower and moderate income households.

There was a serious push to change that. Senate Bill 48 in the 2026 session would have required every county and municipality to adopt an ADU-by-right ordinance by December 1, 2026, and would have barred owner-occupancy requirements and extra parking demands. It passed the Senate 38 to 0 and then died in Messages in the House on March 13, 2026. So as of today, Brevard County's own code is the rule.

Brevard County draws three different boxes

Unincorporated Brevard County, which includes Merritt Island, Suntree, and Viera, does not have one ADU rule. It has three separate categories, and they carry very different rental and metering restrictions.

Category	Code section	Kitchen	Rental allowed
Accessory dwelling unit, detached	Sec. 62-1903	Yes	No rental restriction stated in the section
Guesthouse or servants' quarters, detached	Sec. 62-1932	No, unless the parcel is at least one acre	Expressly prohibited
Single-family second kitchen, inside the home	Sec. 62-1947	Yes, the second kitchen is the point	Expressly prohibited

The detached ADU: a conditional use in Brevard County

Section 62-1903 of the Brevard County code is new, adopted in November 2024. Its conditions:

• One ADU or guesthouse per lot, and the resulting density has to stay consistent with the zoning minimums and the comprehensive plan.
• The primary structure may not have more than one indoor kitchen.
• Size cannot exceed the maximum allowed for accessory structures in that zoning classification. Where no maximum is given, the cap is 50 percent of the size of the principal structure.
• Two stories or more triggers screening of the upper-level sightlines and doubles the required setbacks.
• It may not be located in a coastal high-hazard area, which rules out a meaningful share of the barrier island.
• Cargo shipping containers may not be used as an ADU.
• The application needs a site depiction, a floor plan, and a description of primary building materials.

Notably absent from that list: no owner-occupancy requirement, no ban on a separate utility meter, and no added parking requirement.

Which Brevard County zoning districts allow it

Accessory dwelling units appear in the conditional use list for AU and AU(L), ARR, AGR, PA, REU, RR-1, SEU, SR, EU, EU-1, EU-2, RU-1-13, RU-1-11, RU-1-9, and RU-1-7. They are not listed in GU, RA-2, RP, or the RU-2 multifamily classifications. Because it is a conditional use, expect a zoning application and a public hearing rather than a counter permit. Planned unit developments and recorded HOA covenants, which govern much of Viera, can be stricter than the county baseline, so the district list is not the last word in a deed-restricted community.

The guesthouse route, if you can live without a kitchen

Section 62-1932 allows a detached guesthouse to the rear of the principal structure with no kitchen, the same 50 percent size cap, and minimum 10-foot side and rear setbacks. Use is limited to family members, servants, or temporary guests for a maximum of six months, and it may not be rented. Two thresholds matter: no conditional use permit may be granted on a parcel under half an acre, and none is required at all at one acre or more. At one acre or more, the guesthouse may include a kitchen.

The in-house option: a second kitchen

For a mother-in-law suite inside the house, Section 62-1947 governs. It has to be architecturally integrated so the home still reads as one residence from the street, with direct interior access from the main living area. The area served may not exceed 600 square feet, excluding kitchen and bath. The home stays on a single electrical meter, no portion may be rented, and occupancy is limited to one family. No conditional use permit is required on lots of one acre or more.

Melbourne is the more permissive option

Inside the City of Melbourne, accessory dwellings are handled through design standards in Article VI of the zoning appendix rather than a conditional use hearing. The standards apply in R-A, R-1AAA, R-1AA, R-1A, R-1B, R-2, R-3, REU, R-P, C-1A and C-1, plus the downtown and Eau Gallie art overlay zones.

• Minimum lot size of 14,520 square feet in most of those districts. No minimum in the overlay zones or in REU.
• On properties under one acre, the unit may not exceed 600 square feet of living area. At one acre or more, the cap is 50 percent of the principal structure or 2,000 square feet, whichever is less.
• One accessory dwelling per lot, and no separate utility meter.
• No additional parking space is required, which is a real advantage on an older Melbourne lot.
• A detached unit of 600 square feet or less sits behind the principal dwelling on accessory-structure setbacks. Larger units meet principal-structure setbacks.

Can you rent it out?

Section 62-1903 contains no rental restriction. But Brevard County's zoning definitions classify any dwelling rented for less than 90 days as a "resort dwelling," and a resort dwelling is a commercial use with narrow siting rules under Section 62-1841.5.5. Short-term rental of a Brevard County ADU is not the easy side income people assume, and guesthouses and second kitchens are barred from rental outright.

Permitting on the Space Coast

In unincorporated Brevard County, the Planning and Development Department at 2725 Judge Fran Jamieson Way in Viera issues the building permit, and can be reached at (321) 633-2187. Online permitting is limited to licensed contractors, so owner-builders have to appear in person. The county's impact fee FAQ confirms that additions and remodels of an existing dwelling do not trigger additional impact fees. Whether a detached ADU counts as an addition or as a new dwelling unit for impact fee purposes is worth asking the department directly, because the answer changes your budget.

Is an accessory dwelling unit the same thing as a guest house in Brevard County?

Not in unincorporated Brevard County. An accessory dwelling unit under Section 62-1903 may contain a kitchen. A guesthouse under Section 62-1932 may not, unless the parcel is at least one acre, and it cannot be rented. The City of Melbourne treats the two terms as the same category.

Can I put an ADU on a beachside lot in Brevard County?

Section 62-1903 prohibits accessory dwelling units in a coastal high-hazard area, which covers a significant portion of the barrier island in unincorporated Brevard County. Confirm the coastal high-hazard boundary for the specific parcel before you plan around it.

Does an ADU add value to a Space Coast home?

A permitted, code-compliant accessory unit widens the buyer pool, particularly with multigenerational and relocation buyers. An unpermitted conversion does the opposite: it becomes a disclosure item and a negotiation point. Permitted status is the whole ballgame.

If you are shopping the Space Coast with a multigenerational plan, tell me up front. Zoning classification and jurisdiction are two of the first things I check, and it is cheaper to know before the offer than after the survey. My partner Nichole and I got your back. Reach out anytime at (321) 212-7676 or www.livingspacecoast.com.