Everything homeowners ask about building an ADU in Rochester — answered with 2026 data.
Not yet in most areas. Rochester's current Zoning Code (Chapter 120, 2003) has no ADU use: §120-163.A(1)(g) allows only a rear-yard guesthouse or servants' quarters with no kitchen and no rental, and §120-10 bars adding a unit in R-1. The Zoning Alignment Project code (final draft April 2026) would add ADUs - 800 sq ft, one bedroom, owner-occupied; by right in MDR/HDR and mixed-use districts, by City Planning Commission special permit in LDR - but City Council had not adopted it as of September 20, 2026. Current zoning: None today: Chapter 120 (2003) lists no ADU use in any district; R-1 permits only single-family homes (§120-8) and bars adding units (§120-10); the only accessory living space is a rear-yard guesthouse/servants' quarters with no kitchen and no rental (§120-163.A(1)(g)). The April 2026 ZAP final draft (Table 3-1) would allow ADUs by right in MDR, HDR, BMU, NMU, FMU, DMU, RC, PMV and HV and by special permit in LDR - not adopted as of Sept 20, 2026. Check our full Rochester ADU rules page for the latest status.
ADU construction in Rochester typically costs $105,000-$210,000. The cost per square foot averages $125-$250. Garage conversions are more affordable at $50,000-$120,000, while prefab ADUs cost $75,000-$170,000. Permit fees add Building-permit fees: the schedule was not retrievable (cityofrochester.gov is bot-walled) - confirm with the Bureau of Zoning and Permitting. Zoning fees in §120-206.1 (as amended 2010): special permit $250, use/area variance $250, certificate of zoning compliance $50. to your budget. See our detailed Rochester ADU cost guide.
Detached ADUs in Rochester can be up to Not applicable today. Proposed. Attached ADUs are limited to Not applicable today. Proposed: the same 800 sq ft, one-bedroom cap; an attached ADU must share at least 25% of its wall, floor or ceiling area with the main house. Junior ADUs (JADUs) have a cap of No JADU category in Rochester's code or in the proposed ZAP code. Maximum height is Not applicable today (a detached accessory structure in R-1 is capped at 15 ft, §120-12.A). Proposed: a newly built ADU is limited to 15 ft or the height of the main house, whichever is less (Sec. 3.7.A.8); a converted existing garage is not 'newly constructed' (FGEIS p. 26). You are allowed up to None today. Proposed: one ADU per lot, only with a single-family detached house on a qualifying lot.
Rear setback: Not applicable today. Proposed: the draft sets no zoning setback for ADUs - 'all setbacks for the ADU shall be governed by the NYS Building and Uniform Fire Prevention Code' (Sec. 3.7.A.9); a detached ADU must be in the rear yard (3.7.A.5). Side setback: Not applicable today. Proposed: governed by the NYS Uniform Code, not by a zoning distance (Sec. 3.7.A.9); the generic 3 ft accessory-structure setback in Sec. 14.1.F applies only to structures the Building Code does not regulate. Front setback: Not applicable today. Proposed: an attached ADU may not extend past the existing front building line (Sec. 3.7.A.10); a detached ADU is confined to the rear yard (3.7.A.5). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
Not applicable today (§120-173 requires 1 space per dwelling unit for single- and two-family homes). Proposed: Table 15-1 lists no ADU parking requirement - spaces are calculated on the principal use, 1 space for a single-family house (Sec. 15.3) - and an ADU may not have its own driveway (Sec. 3.7.A.12). 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 applicable today. Proposed: required - the ADU definition (Sec. 3.9) says the owner must live in either the main house or the ADU, and because it sits in the definition it cannot be waived by special permit or use variance; proof is a utility bill or account statement at permit or C of O (FGEIS p. 26). 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 Rochester is typically Not published. Under the proposed code a special permit decision is due within 62 days after the Planning Commission closes its public hearing (Sec. 20.11.D.3); building-permit review times are not posted. Plan check: Not published; part of the building-permit review by the Bureau of Zoning and Permitting. Pre-approved plans availability: None - Rochester publishes no pre-approved ADU plan set (Sept 2026).
Average ADU rental income in Rochester: 1-bedroom units rent for $1,000-$1,300/month, 2-bedroom units for $1,250-$1,600/month. Short-term rentals: Not addressed for ADUs; a separate ZAP short-term rental amendment (April 2026 draft, not adopted) would regulate STRs by district and owner-occupancy. Expected ROI: Not estimated - no ADU can be permitted today; HUD FY2026 FMR $1,256/mo (1-BR) for the Rochester MSA against a $105,000-$210,000 build.
The minimum lot size for an ADU in Rochester is None proposed for ADUs. Today an R-1 detached house needs a 5,000 sq ft lot (§120-11.B) and a two-family conversion needs a 6,000 sq ft lot (§120-166.A(3)). 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 Rochester, a garage conversion typically costs $50,000-$120,000. 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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