Everything homeowners ask about building an ADU in Rochester — answered with 2026 data.
Yes, ADUs are allowed in Single-family residential in Rochester, NY. The maximum size for a detached ADU is 850 sq ft. Attached ADUs can be up to 750 sq ft. Rochester has an ADU-friendliness score of 6/10. Check our full Rochester ADU rules page for complete zoning details.
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 $1,900-$3,300 to your budget. See our detailed Rochester ADU cost guide.
Detached ADUs in Rochester can be up to 850 sq ft. Attached ADUs are limited to 750 sq ft. Junior ADUs (JADUs) have a cap of Not allowed. Maximum height is 35 feet. You are allowed up to 1 ADU per lot on a qualifying lot.
Rear setback: 15 feet. Side setback: 5 feet. Front setback: 20 feet. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
1 space per unit. 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. 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 50-70 days. The plan check process takes approximately 2-3 weeks. Pre-approved plans availability: Limited availability.
Average ADU rental income in Rochester: 1-bedroom units rent for $1,050-$1,450/mo/month, 2-bedroom units for $1,350-$1,850/mo/month. Short-term rentals: Not typically permitted. Expected ROI: 8-12% annual return.
The minimum lot size for an ADU in Rochester is 4,500 sq ft. 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.