ADU · Erie County
Can you build an ADU in Tonawanda, NY?
Town of Tonawanda has 10 districts. 6 districts allow ADUs with occupancy restrictions, 4 do not. Check your address to confirm the district that applies to your parcel:
What the Tonawanda code indicates by district
The table below shows how each district treats ADUs, alongside the lot and setback standards that govern a second unit. District boundaries and conditions vary, so treat this as a starting point and confirm the district that applies to your parcel.
| District | Min lot | Setbacks F / S / R | Max height | ADU |
|---|---|---|---|---|
| R-1 Single-Family Residential | 0.103 ac | 25 / 2 / 25 ft | 35 ft | Occupancy restricted |
| R-2 Two-Family Residential | 0.103 ac | 25 / 2 / 25 ft | 35 ft | Occupancy restricted |
| MR Mixed Residential | 0.103 ac | 20 / 2 / 25 ft | 45 ft | Occupancy restricted |
| MU-N Mixed Use Neighborhood (§ 215-21.1 to 215-21.5) — the secondary-corridor mixed-use district. § 215-21.2A states the purpose as facilitating investment along established secondary commercial corridors such as DELAWARE AND ENGLEWOOD AVENUE, per the Town's Comprehensive Plan. Table 21-b prints "0/20" and Note (2) says THE LARGER SHALL BE THE MAXIMUM FRONT SETBACK REQUIREMENT — so the minimum front setback is ZERO and 20 ft is a CEILING the building may not exceed. frontSetback is therefore recorded as 0, which is correct and is not a missing value: a building may sit on the front lot line, and one set back more than 20 ft is non-conforming. That is a build-to rule, the opposite of a conventional setback, and it means a suburban-style parking-in-front layout is not permitted here. Minimum lot area is tiered by use: 4,500 sq ft for a single- or two-family dwelling (0.103 acre, recorded, and identical to the R-1/R-2/MR figure), 2,000 sq ft PER UNIT for multifamily, and 10,000 sq ft for any other use. Minimum lot width 50 ft for a residential use (recorded) and 70 ft for any other use. Side setback 5 ft, rising to 10 ft where adjacent to a residential use or district (Note 3); accessory 3 ft, rising to 5 ft. Rear setback 25 ft primary, 5 ft accessory. Maximum height 35 ft primary, 16 ft residential accessory, 15 ft nonresidential accessory. — driveways and parking count — and it pairs with a stated MINIMUM OPEN SPACE OF 15% in grass, landscaped or natural area, the two being exact complements. MU-N ALSO CAPS BUILDING FOOTPRINT, WHICH THE OTHER MIXED-USE DISTRICTS DO NOT: a nonresidential primary structure may not exceed 5,000 sq ft, a private garage 900 sq ft, and any other enclosed accessory building 180 sq ft (Note 4 exempts pools, patios and playgrounds, and § 215-24.4 caps how many accessory structures are permitted). The 5,000 sq ft footprint cap is the binding constraint on a commercial building here, well before the 85% coverage figure. | 0.103 ac | 0 / 5 / 25 ft | 35 ft | Occupancy restricted |
| MU-GC Mixed Use General Commercial (§ 215-21.1 to 215-21.5) — the primary commercial district, more intensive than MU-N and with a genuinely conventional front setback. Table 21-b prints "30/50" for the front, and under Note (2) that is a MINIMUM OF 30 FT AND A MAXIMUM OF 50 FT — recorded as 30. Unlike MU-N, whose minimum is zero, MU-GC requires a real front yard but still caps how deep it may be, so a deep parking apron in front of the building is not permitted. Minimum lot area 6,500 sq ft for a single- or two-family dwelling (0.149 acre, recorded), 2,000 sq ft per unit for multifamily, and 15,000 sq ft for any other use — note the other-use figure is half again what MU-N asks. Minimum lot width 50 ft residential (recorded), 70 ft other use. Side setback 5 ft, rising to 15 FT where adjacent to a residential use or district — a steeper step than MU-N's 10 ft. Accessory side 3 ft rising to 5 ft. Rear setback 25 ft primary, 5 ft accessory. — a four-storey building is non-conforming even under 45 ft. Accessory structures 16 ft residential, 15 ft nonresidential. Maximum lot coverage 85% of structures AND IMPERVIOUS SURFACES combined, with a complementary 15% minimum open space in grass, landscaped or natural area. NO BUILDING FOOTPRINT CAP APPLIES HERE, unlike MU-N — Table 21-b prints "—" in all three footprint rows for this district, so the 5,000 sq ft limit that constrains a commercial building in MU-N does not bind in MU-GC. That is the substantive difference between the two commercial districts and it matters more than the setbacks. | 0.149 ac | 30 / 5 / 25 ft | 45 ft | Occupancy restricted |
| MU-W Mixed Use Waterfront (§ 215-21.1 to 215-21.5) — the Niagara River waterfront district, and THE MOST DISCRETIONARY DISTRICT IN THE CHAPTER. Nothing about the buildable envelope on a MU-W parcel can be established from the code — it comes out of the Planning Board process, so an early pre-application conversation is not optional here, it is the only way to get a number. THE FEW FIXED STANDARDS: a single- or two-family dwelling is shown as "—", i.e. no minimum lot area is stated for it; minimum lot width 60 ft for a residential use (recorded, and the largest residential width in the mixed-use group) and 70 ft for any other use; front setback 20 ft minimum with a 50 ft MAXIMUM under Note (2), recorded as 20; and A MINIMUM OPEN SPACE OF 35% in grass, landscaped or natural areas, more than double the 15% required in MU-N and MU-GC. That 35% open-space floor is the one hard density constraint the district publishes, and because the matching coverage row is SPR, open space rather than coverage is what actually limits site intensity here. A SEPARATE SHORELINE RULE EXISTS AND IS ALSO SPR: Table 21-b carries a distinct "Primary use, at shoreline" front-setback row, so a waterfront-facing frontage is reviewed on its own terms rather than under the 20/50 street setback. The Local Waterfront Overlay (LWO, § 215-23) may also apply on top of this district. | — | 20 / - / - ft | — | Occupancy restricted |
| MU-I Mixed Use Industrial (§ 215-22.1 to 215-22.6) — the lighter of the two industrial districts, intended to transform industrial areas into mixed economic centres rather than to preserve heavy industry. Minimum lot area 30,000 sq ft (0.689 acre) and minimum lot width 80 ft — both stated flat, with no per-use tiering, which is a different table shape from the mixed-use districts. Front setback 40 ft. Side setback 10 ft primary, rising to 25 FT where adjacent to a residential use or district under Table 22-b Note (1); accessory 5 ft rising to 15 ft. Rear setback 25 ft primary (stated flat, with no residential-adjacency step, unlike GI); accessory 5 ft rising to 15 ft. — accessory structures are held to 25 ft. Maximum lot coverage 65% of structures AND IMPERVIOUS SURFACES, materially tighter than the 85% allowed in the commercial districts, with a complementary 35% MINIMUM OPEN SPACE in grass, landscaped or natural area. That 35% green requirement on an industrial site is unusual and is the standard most likely to bind a large-footprint building or a truck yard, well before the height limit does. | 0.689 ac | 40 / 10 / 25 ft | 80 ft | No |
| GI General Industrial (§ 215-22.1 to 215-22.6) — the town's heavy industrial district, on the Niagara River industrial corridor. Minimum lot area 40,000 sq ft (0.918 acre) and minimum lot width 100 ft, both stated flat. Front setback 40 ft, the same as MU-I. Side setback 25 ft primary rising to 50 FT where adjacent to a residential use or district (Note 1); rear setback 25 ft primary rising to 50 ft on the same test; accessory yards 5 ft rising to 25 ft on both side and rear. So a GI parcel that backs onto housing must hold 50 ft on that boundary, where an MU-I parcel in the same position holds 25 ft. The recorded 25 ft side and rear are the non-adjacent base figures. Maximum height 80 ft primary, 25 ft accessory — matching MU-I. Maximum lot coverage 75% of structures AND IMPERVIOUS SURFACES, looser than MU-I's 65% but tighter than the commercial districts' 85%, with a complementary 25% minimum open space in grass, landscaped or natural area. Note the pairing runs the opposite way to intuition: the HEAVIER industrial district is allowed MORE impervious cover and less green space than the mixed-use industrial one, because MU-I is being held to a higher amenity standard as it transitions. | 0.918 ac | 40 / 25 / 25 ft | 80 ft | No |
| CF Community Facility (§ 215-23.1 to 215-23.7) — the institutional district: schools, municipal buildings, places of worship and similar public and quasi-public uses. Recorded because it carries a full dimensional schedule in Table 23-b and because institutional sites are often the largest redevelopable parcels in a built-out town like this one. Minimum lot area 20,000 sq ft (0.459 acre), minimum lot width 80 ft. Front setback 20 ft — the shallowest primary front setback of any non-mixed-use district in the chapter, and note it is stated flat with NO maximum, so the build-to ceiling that applies in MU-N, MU-GC and MU-W does not apply here. Side setback 10 ft primary rising to 25 ft where adjacent to a residential use or district (Table 23-b Note 1); accessory 5 ft rising to 10 ft. Rear setback 25 ft primary; accessory 5 ft rising to 10 ft. Maximum height 45 ft AND three stories, both limits applying together, exactly as in MU-GC. Maximum lot coverage 65% of structures AND IMPERVIOUS SURFACES — the same figure as MU-I — with a complementary 35% minimum open space in grass, landscaped or natural areas. On a school or church site with a large parking requirement that 35% green floor is usually the standard that binds first. | 0.459 ac | 20 / 10 / 25 ft | 45 ft | No |
| OS Open Space (§ 215-23.1 to 215-23.7) — parks and protected open land, and it is recorded rather than omitted because it carries real published figures that make the extent of the restriction explicit. Those are exact complements, and they mean an OS parcel is 85% grass, landscaped or natural area by rule — so while OS land is not undevelopable, no more than a seventh of it may become structures and impervious surface combined. NO MINIMUM LOT AREA AND NO MINIMUM LOT WIDTH ARE STATED — Table 23-b prints "—" in both rows — so those fields are null by design rather than unread; there is no minimum parcel to create in this district because it is not a subdivision district. Front setback 20 ft, stated flat with no maximum. Side setback 25 ft primary (stated flat, with no residential-adjacency step, unlike CF) and 5 ft rising to 10 ft for accessory structures. Rear setback 25 ft primary, accessory 5 ft rising to 10 ft. Maximum height 35 ft AND 2.5 stories, both applying — the lowest height allowance in the chapter, matching the residential districts. | — | 20 / 25 / 25 ft | 35 ft | No |
ADUs vs. short-term rentals in Tonawanda
Short-term rentals allowed with local rules for Town of Tonawanda. Short-term rentals are regulated as a named use under § 215-24.7 of the Zoning Code, which covers bed-and-breakfast and short-term rental uses together. Such a use must be duly licensed and registered as a business and is subject to the Erie County hotel occupancy tax (§ 215-24.7A). Critically, it is allowed only in an OWNER-OCCUPIED single-family dwelling or a detached accessory structure on the same lot (§ 215-24.7B), and is barred on a nonconforming lot or in a nonconforming structure (§ 215-24.7C) — so a non-owner-occupied whole-house rental does not qualify. New York State's 2025 short-term rental registry (Ch. 99 of the Laws of 2025) separately requires every host statewide to register the unit regardless of local law. Confirm with Town of Tonawanda at (716) 877-8800 before listing. These are separate questions from whether you can build an ADU — a unit you're allowed to add isn't automatically one you're allowed to rent nightly, so check both.
Good to know
- Residential lot minimum0.103 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityNational Grid territory.
- Building dept(716) 877-8800
- Last reviewed2026-08-21
ADU FAQ — Tonawanda, NY
Are ADUs allowed in Tonawanda, NY?
Town of Tonawanda has 10 districts. 6 districts allow ADUs with occupancy restrictions, 4 do not. Check your address with the free ADU checker, or confirm with the building department at (716) 877-8800.
Do I need a special permit for an ADU in Tonawanda?
No district in Town of Tonawanda requires a special-use permit for an ADU - 6 districts allow ADUs with occupancy restrictions, 4 do not. Site-plan review or a building permit may still apply.
Can I use an ADU as a short-term rental in Tonawanda?
Short-term rentals allowed with local rules for Town of Tonawanda. ADU occupancy and short-term-rental rules are separate: an ADU you can build isn't automatically one you can rent nightly. Confirm both before you count on STR income.
What an ADU costs to build in Tonawanda
Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $200k–260k at a standard finish, and the per-square-foot rate comes in above a full house because the kitchen, bath, panel and heating plant cost the same either way. See the full cost to build an ADU in Tonawanda, priced by size.
More on Tonawanda: Full zoning for new construction · ADU build cost · House build cost · All Erie County towns
ADU information for Town of Tonawanda is compiled from the municipal code (last reviewed 2026-08-21) and provided for decision-support only — not legal or architectural advice. ADU eligibility, size, owner-occupancy and permit conditions vary by district and often carry exceptions; verify with the building department at (716) 877-8800 before relying on any answer. Source: Offsite / Aldo zoning dataset, municipalData.js.