Zoning & Size Limits
| Requirement | Jersey City, NJ | Montclair, NJ |
|---|
| Allowed Zones | R-1, R-2, RH-1 and RH-2 zones (check the Jersey City Interac | R-O, R-O(a), R-1 and R-2 zones, on lots containing one- or t |
| Max Size (Detached) | No square-footage cap — size is limited by the 18 ft/2-story height limit, setbacks and lot coverage (R-1: maximum lot coverage increases by an additional 5% for an ADU; R-2: 80% lot coverage; RH-1: 75% lot / 55% building coverage; RH-2: 75% lot coverage) | 300-800 sq ft, and no more than 40% of the habitable area of the principal building, whichever is less; no more than 3 rooms excluding kitchen and bathroom; detached ADUs must be located in the rear yard |
| Max Size (Attached) | Not permitted — all Jersey City ADUs must be detached from the principal structure; attached/ground-floor garage conversions are a separate conditional use (LDO §345-41 G.1, R-1 zone, Planning Board approval, driveway and curb cut must be removed) | Same standard — 300-800 sq ft and no more than 40% of the principal building's habitable area; may be part of an expanded or remodeled dwelling |
| Max Height | 18 feet or 2 stories (18 feet in RH-1) | Detached ADUs follow accessory-building standards; |
| Parking Required | ADUs are exempt from parking requirements (in R-2, follow R- | At least 1 off-street parking space required for the ADU |
| Owner Occupancy | No owner-occupancy requirement appears in the LDO ADU standa | Required — the property owner must occupy either the primary |
Setback Requirements
| Setback | Jersey City, NJ | Montclair, NJ |
|---|
| Rear Setback | R-1: 2 ft (per building code); R-2: 3 ft; RH-1 and RH-2: none | Accessory-building setbacks of the underlying zone apply — confirm with the Montclair Department of Planning & Community Development |
| Side Setback | R-1: 2 ft; R-2: 3 ft; RH-1 and RH-2: 2 ft | Accessory-building setbacks of the underlying zone apply — confirm with the Montclair Department of Planning & Community Development |
| Front Setback | ADU sits behind the principal structure; corner, c | Detached ADUs must be in the rear yard (not permit |
Permits & Timeline
| Detail | Jersey City, NJ | Montclair, NJ |
|---|
| Permit Timeline | Confirm with the Division of Zoning — no published ADU-specific timeline | Confirm with the Montclair Department of Planning & Community Development — no published ADU-specific timeline |
| Permit Fees | Confirm with the Division of Zoning and Division of Construction Code Official — no published ADU fee schedule | An ADU zoning permit fee applies (see the township's ADU zoning permit application); confirm the current amount and construction permit fees with the Planning Department |
| Impact Fees | No California-style ADU impact fees; sewer/water connection | No California-style ADU impact fees; sewer connection charge |
| Pre-Approved Plans | None offered as of July 2026 | None offered as of July 2026 |
Construction Costs
| Cost | Jersey City, NJ | Montclair, NJ |
|---|
| Avg Build Cost | $150,000-$300,000 | $175,000-$325,000 |
| Cost Per Sq Ft | $200-$350 | $225-$375 |
| Garage Conversion | $60,000-$150,000 (detached garages only — attached-garage conversions are a separate conditional-use dwelling unit, not an ADU) | $65,000-$150,000 |
| Prefab ADU | $120,000-$250,000 installed (tight urban lot access can add crane/site costs) | $125,000-$250,000 installed |
Rental Income Potential
| Rental | Jersey City, NJ | Montclair, NJ |
|---|
| 1BR Avg Rent | $2,900-$3,400/mo | $2,200-$2,800/mo |
| 2BR Avg Rent | $3,900-$4,600/mo | $2,800-$3,500/mo |
| Short-Term Rentals | Heavily restricted — Jersey City's short-term rental ordinan | Not addressed in the township's ADU summary — confirm short- |
| Est. ROI | 8-12% gross annual return (long-term rental, before taxes and financing) | 7-10% gross annual return (long-term rental, before taxes and financing) |
Which City Is Better for ADUs?
Jersey City scores 7/10 while Montclair scores 6/10 on our ADU-friendliness index.
Jersey City edges ahead overall. Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
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