Everything homeowners ask about building an ADU in Henderson — answered with 2026 data.
Yes, ADUs are allowed in the RS (RS-1/2/4/6/8), RM (RM-10/16), RH (RH-24/36), MC and MN districts — not RMH, MR, or any commercial or industrial district — subject to use-specific standards rather than a conditional use permit (“S” in Table 19.9.1-2; standards at Sec. 19.9.4.B.6) in Henderson, NV. The maximum size for a detached ADU is the greater of 25% of the principal dwelling's floor area or 1,000 sq ft — a guaranteed minimum, not a cap (Sec. 19.9.4.B.6.b.ii). Tiny-house ADUs max 400 sq ft excluding lofts; an attached garage doesn't count toward ADU size. Attached ADUs can be up to the greater of 25% of the principal dwelling's floor area or 1,000 sq ft — the same rule as detached ADUs; Henderson sets no separate attached-ADU percentage. Henderson has an ADU-friendliness score of 7/10. Check our full Henderson ADU rules page for complete zoning details.
ADU construction in Henderson typically costs $130,000-$250,000. The cost per square foot averages $140-$280. Garage conversions are more affordable at $60,000-$140,000, while prefab ADUs cost $90,000-$200,000. Permit fees add Confirm with Henderson Development Services Center to your budget. See our detailed Henderson ADU cost guide.
Detached ADUs in Henderson can be up to the greater of 25% of the principal dwelling's floor area or 1,000 sq ft — a guaranteed minimum, not a cap. Attached ADUs are limited to the greater of 25% of the principal dwelling's floor area or 1,000 sq ft — the same rule as detached ADUs; Henderson sets no separate attached-ADU percentage. Junior ADUs (JADUs) have a cap of not a separate category — an ADU built inside the primary residence follows the same size rule. Maximum height is No explicit height cap in the ADU standards; height instead drives setbacks at a 14-ft threshold. RS primary buildings cap at 35 ft and residential accessory structures at 24 ft — confirm with Henderson which applies to a detached ADU.. You are allowed up to 1 accessory dwelling unit per lot on a qualifying lot.
Rear setback: 5 ft for a detached ADU 14 ft or less in height; taller ADUs must meet the main house's rear setback (RS-1/RS-2: 25 ft; RS-4/RS-6/RS-8: 15 ft). Detached ADUs need 6 ft of separation from other buildings, or a connecting roof.. Side setback: Interior side: 5 ft for a detached ADU 14 ft or less in height; taller ADUs meet the main house's (RS-1/RS-2: 10 ft; RS-4/RS-6/RS-8: 5 ft). Corner side always matches the main house's.. Front setback: Must match the principal dwelling's front setback (RS-1/RS-2: 20 ft; RS-4/RS-6/RS-8: 10 ft; RM/RH: 10 ft).. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
1 off-street space per ADU (Sec. 19.12.3, residential parking table) — at Nevada AB 396's ceiling, which bars local ordinances from requiring more than one space for an ADU.. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required — no owner-occupancy condition appears in the ADU standards, making Henderson the Las Vegas Valley exception. Occupancy follows the Code's “family unit” rule: any number of related people, or up to 6 unrelated people.. 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 Henderson is typically Confirm with Henderson Development Services Center. Plan check: Confirm with Henderson Development Services Center. Pre-approved plans availability: No city pre-approved ADU plan program identified as of August 2026.
Average ADU rental income in Henderson: 1-bedroom units rent for $1,300-$1,650/month, 2-bedroom units for $1,550-$1,900/month. Short-term rentals: Not addressed in the ADU standards. Rentals under 30 days are a separate use (“S” in RS/RM/RH) requiring city registration and a Nevada business license — confirm with Henderson whether an ADU may be registered as one.. Expected ROI: 5-8% annual return.
The minimum lot size for an ADU in Henderson is None for ADUs. District minimums govern lot creation only (RS-4: 10,000 sq ft; RS-6: 6,000; RS-8: 4,000; RM: 3,000), so a typical 6,000 sq ft RS-6 tract lot qualifies.. 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 Henderson, a garage conversion typically costs $60,000-$140,000. 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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