Everything homeowners ask about building an ADU in Jacksonville — answered with 2026 data.
Yes, ADUs are allowed in Accessory use on any conforming residential lot in the Agriculture, Rural Residential, Low Density Residential, Medium Density Residential and Residential-Professional-Institutional land-use categories (FLUE Policy 3.1.29, Ord. 2022-447-E), i.e. the RR, RLD and RMD zoning districts. The former RLD-TND-only limit was deleted from Sec. 656.305 by Ord. 2022-448-E. A PUD is governed by its own written description, so read it first. in Jacksonville, FL. The maximum size for a detached ADU is Building footprint capped at the lesser of 25% of the principal house's gross floor area or 750 sq ft (Sec. 656.403(g)(3)): a 2,000 sq ft house allows a 500 sq ft footprint, a 3,000 sq ft house the full 750 sq ft. The cap is on footprint, not floor area, and the unit must be behind the house and outside all required yards ((g)(1), (g)(4)). Attached ADUs can be up to Same footprint cap: lesser of 25% of the house's gross floor area or 750 sq ft. Jacksonville has an ADU-friendliness score of 5/10. Check our full Jacksonville ADU rules page for complete zoning details.
ADU construction in Jacksonville typically costs $150,000-$300,000. The cost per square foot averages $150-$360. Garage conversions are more affordable at $65,000-$130,000, while prefab ADUs cost $125,000-$200,000. Permit fees add Building permit fees are set by Ordinance Code Chapter 320 on the gross floor area under roof, plus separate electrical, plumbing and mechanical permit fees; the city publishes no ADU-specific figure, so price it in JaxEPICS or with the Building Inspection Division (904-255-8500). to your budget. See our detailed Jacksonville ADU cost guide.
Detached ADUs in Jacksonville can be up to Building footprint capped at the lesser of 25% of the principal house's gross floor area or 750 sq ft. Attached ADUs are limited to Same footprint cap: lesser of 25% of the house's gross floor area or 750 sq ft. Junior ADUs (JADUs) have a cap of No junior ADU category in Jacksonville's Zoning Code. A unit carved out of the house is an attached ADU: same footprint cap and no internal door between the units (Sec. 656.403(g)(3), (g)(7)). Maximum height is Sec. 656.403(g)(5) applies the accessory-structure height rule of Sec. 656.403(d): a unit over 15 ft tall may not exceed the height of the house (it may rise to 35 ft only on an RR-Acre lot or a lot of at least one acre). The district ceiling for any structure in the RLD districts is 35 ft (Sec. 656.305(g)). You are allowed up to One ADU per conforming residential lot, allowed regardless of the land-use category's density limit on a qualifying lot.
Rear setback: The ADU may not stand in any required yard (Sec. 656.403(g)(4) and (a)(2)), so it must meet the house's district rear setback: 10 ft in every RLD district, RLD-120 through RLD-TND (Sec. 656.305(f)). RMD and PUD lots: confirm the figure with the Zoning Section (904-255-8300). Side setback: The house's district side yard applies: 5 ft in RLD-90, RLD-80, RLD-70, RLD-60 and RLD-50; 3 ft in RLD-40 and RLD-TND; 7.5 ft in RLD-120, RLD-100A and RLD-100B (Sec. 656.305(f)). The 5-ft-from-lot-line allowance for small accessory structures in Sec. 656.403(d)(1) does not cover a dwelling ((a)(2), (g)(4)). Front setback: Must be located behind the primary structure (Sec. 656.403(g)(1)) and never in a required front yard (Sec. 656.403(a)). District front yards are 20 ft in RLD-100B through RLD-40 and 25 ft in RLD-120 and RLD-100A (Sec. 656.305(f)); on a corner lot both street frontages count. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
No ADU-specific parking requirement in Sec. 656.403(g); the house keeps the off-street parking that Part 6 of Chapter 656 requires for a single-family dwelling. Confirm with the Zoning Section (904-255-8300) whether an added space is expected on your lot. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Required in effect: the lot must carry an existing Duval County homestead exemption, or qualify for one that the owner has applied for through the Property Appraiser (Sec. 656.403(g)(6)), which makes the property the owner's permanent residence. Ordinance 2024-870 as filed would have deleted this rule; the Land Use and Zoning Committee struck that section on January 7, 2025 and the ordinance enacted January 14, 2025 left (g)(6) intact. Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Jacksonville is typically The city publishes no review clock for residential plan review; JaxEPICS returns comments once every discipline has reviewed the set. A permit expires after 180 days without work (Building Inspection Division FAQ). Plan check: Electronic plan review in JaxEPICS by every discipline, including the fire marshal; the Florida Building Code 8th Edition (2023) and NEC 2020 apply. Lots in a FEMA flood zone are also reviewed by Development Services' Review Group. Pre-approved plans availability: None offered by the city.
Average ADU rental income in Jacksonville: 1-bedroom units rent for $1,000-$1,350/month, 2-bedroom units for $1,350-$1,600/month. Short-term rentals: Not addressed in Sec. 656.403(g). Because the lot must keep its homestead exemption, the property has to remain the owner's permanent residence; confirm with the Zoning Section before planning a short-term rental. Expected ROI: 4-8% annual return (about $12,000-$16,000 a year in rent on a $150,000-$300,000 unit, before taxes, insurance, vacancy and upkeep).
The minimum lot size for an ADU in Jacksonville is No ADU-specific minimum lot. The lot must be a conforming residential lot with a conforming single-family house (FLUE Policy 3.1.29; Sec. 656.403(g)(7)). District minimums apply to the lot itself, e.g. RLD-60 is 6,000 sq ft and 60 ft wide, RLD-40 is 4,000 sq ft and 40 ft wide (Sec. 656.305(d)); all buildings together may cover at most 50% of an RLD-60, RLD-50 or RLD-40 lot (Sec. 656.305(e)). This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Jacksonville, a garage conversion typically costs $65,000-$130,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
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