Milton · ADU cost
What it costs to build an ADU in Milton, NY
An 800 sq ft accessory dwelling unit in Milton runs roughly $200k–260k, or about $249–327/sq ft, and that per-square-foot figure sits deliberately above the $204–268/sq ft a full house costs here. An ADU still needs one whole kitchen, one whole bath, its own service panel and its own heating plant no matter how small you draw it, and those costs do not shrink with the floor plan, so they land on half the square footage and push the rate up. Whether the town will let you build one is a separate question from what it costs, and it gets answered parcel by parcel rather than townwide, since the Town of Milton maps 9 districts that treat accessory units differently from one another, so read the table below as a starting point rather than a verdict.
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ADU cost by size in Milton
Standard finish, slab on grade, on a flat and clear part of the lot, general-contractor margin included. These are structure costs at Saratoga County pricing, before the service and septic work a second dwelling can trigger.
| Size | Type | $ / sq ft | Estimated total |
|---|---|---|---|
| 400 sq ft | Studio | $331–$433 | $130k–175k |
| 600 sq ft | One bedroom | $276–$362 | $165k–215k |
| 800 sq ft | One bedroom, larger | $249–$327 | $200k–260k |
| 1,000 sq ft | Two bedroom | $233–$305 | $235k–305k |
400 sq ft — One room plus a bath. Garage conversions and small backyard cottages land here.
600 sq ft — The most common detached build - a real bedroom, full kitchen, one bath.
800 sq ft — Room for a proper living area. Still a single bath and one kitchen.
1,000 sq ft — About as large as most codes allow an accessory unit to go.
Why the rate is higher than a house
The systems below are priced for an 800 sq ft unit. The middle column is what each system would cost if it simply shrank with the floor plan; the left column is what it actually costs once you account for the equipment a dwelling needs one of regardless of size. The gap between the two columns is the whole reason small builds price the way they do.
| System | $ / sq ft in an ADU | If it scaled with floor area | Fixed per unit |
|---|---|---|---|
| Site work | $7–$11 | $7 | — |
| Foundation | $16–$23 | $16 | — |
| Framing | $25–$32 | $25 | — |
| Envelope - roof, siding, windows | $32–$41 | $32 | — |
| Plumbing | $28–$34 | $16 | 55% |
| Electrical | $18–$24 | $13 | 35% |
| HVAC | $23–$28 | $15 | 45% |
| Insulation | $7–$9 | $7 | — |
| Interior finishes | $32–$43 | $27 | 15% |
| Millwork & cabinetry | $18–$28 | $11 | 55% |
The fixed-per-unit share is a modeling assumption, not a figure from the code: it is our estimate of how much of each system's budget buys equipment a dwelling needs exactly one of - a kitchen rough-in, a bath group, a service panel, a heating plant - and therefore does not shrink when the unit does. Site work, foundation, framing, envelope and insulation are treated as scaling straight with floor area, which understates the premium slightly, because a small building carries more envelope per square foot of floor than a large one.
What the Milton code says about accessory units
Whether you can build one, and how large, is decided by the district your parcel sits in rather than by the town as a whole. The table shows how each mapped district treats ADUs alongside the lot and setback standards a second unit still has to fit inside. District boundaries and conditions vary, so treat it as a starting point and confirm the district that applies to your parcel.
| District | Min lot | Setbacks F / S / R | Max height | ADU |
|---|---|---|---|---|
| R1 Residential | 0.5 ac | 50 / 20 / 50 ft | 35 ft | Special permit |
| R2 Rural | 5 ac | 150 / 50 / 75 ft | 35 ft | Special permit |
| R2os Rural Open Space Incentive | 1 ac | 50 / 20 / 75 ft | 35 ft | Special permit |
| TC Town Center | — | 10 / - / 20 ft | 50 ft | Special permit |
| MU Mixed Use | 0.25 ac | 30 / 25 / 30 ft | 35 ft | Special permit |
| CMU Corridor Mixed Use | 0.25 ac | 75 / 12 / 25 ft | 35 ft | Special permit |
| H1 Rock City Falls Hamlet | 1 ac | 15 / 12 / 50 ft | 35 ft | Special permit |
| H2 West Milton Hamlet | 1 ac | 15 / 12 / 50 ft | 35 ft | Special permit |
| A Airport | 2 ac | 75 / 50 / 75 ft | 35 ft | No |
R1 Residential - Density, not the half-acre lot minimum, sets how many homes a parcel yields: 1 dwelling unit per acre without sewer and water, 2 with them.
- Actual lot area may be significantly larger than the minimum, based on the maximum dwelling unit density.
- A structure may be built anywhere within the setbacks of the two adjacent structures on the same side of the street, and a corner lot may use the setback of the adjacent lot on each side.
- The total coverage cap counts all impervious surface, buildings and paving together; the building coverage cap is the footprint alone.
R2 Rural - The open space incentive option, R2os, sets a one-acre lot minimum, 100 ft of lot width and a 50 ft front yard in place of these figures. Sewer and water service does not raise the density here.
- Actual lot area may be significantly larger than the minimum, based on the maximum dwelling unit density.
- A structure may be built anywhere within the setbacks of the two adjacent structures on the same side of the street, and a corner lot may use the setback of the adjacent lot on each side.
- The total coverage cap counts all impervious surface, buildings and paving together; the building coverage cap is the footprint alone.
R2os Rural Open Space Incentive - In an open space subdivision, the building area of new lots must stay at least 150 ft from adjacent properties outside the subdivision and from preexisting town, county and state roads.
- The side and rear yards shown apply to interior lot lines within the subdivision.
- Density is the same as conventional R2, so clustering buys smaller lots and preserved open space, not more houses.
- The Planning Board may grant a discretionary bonus of up to 50% above the maximum density under § 180-30.
- A structure may be built anywhere within the setbacks of the two adjacent structures on the same side of the street, and a corner lot may use the setback of the adjacent lot on each side.
- The total coverage cap counts all impervious surface, buildings and paving together; the building coverage cap is the footprint alone.
TC Town Center - The front yard is a build-to band of at least 10 ft and no more than 15 ft. Density rises from 1 to 16 units per acre with sewer and water, but 16 is the intended maximum for an apartment building.
- Actual density may be significantly less than 16 through site plan review, including compatibility with residential abutters.
- Where a utility easement prevents building to the prescribed setback, the structure is placed as close as possible to the street line.
- A multifamily dwelling is permitted by right. One-family and two-family dwellings are prohibited.
- There is no minimum lot area and no side yard requirement in TC.
- The total coverage cap counts all impervious surface, buildings and paving together; the building coverage cap is the footprint alone.
MU Mixed Use - Density rises from 1 to 16 dwelling units per acre with sewer and water. Multifamily and two-family dwellings are permitted by right, while a one-family dwelling needs a special permit.
- Actual lot area may be significantly larger than the minimum, based on the maximum dwelling unit density.
- In the residential districts a structure may be built anywhere within the setbacks of the two adjacent structures on the same side of the street; a corner lot may use each adjacent lot's setback.
- The total coverage cap counts all impervious surface, buildings and paving together; the building coverage cap is the footprint alone.
CMU Corridor Mixed Use - Buildings set back 75 ft or more from Route 50 may be up to 50 ft tall; the 35 ft limit applies to buildings fronting Route 50. Density rises from 1 to 16 units per acre with sewer and water.
- A multifamily dwelling is permitted by right. One-family and two-family dwellings are prohibited.
- Actual lot area may be significantly larger than the minimum, based on the maximum dwelling unit density.
- The total coverage cap counts all impervious surface, buildings and paving together; the building coverage cap is the footprint alone.
H1 Rock City Falls Hamlet, H2 West Milton Hamlet - Density rises from 1 to 3 dwelling units per acre with sewer and water. One-family dwellings are permitted by right and two-family dwellings need a special permit.
- Actual lot area may be significantly larger than the minimum, based on the maximum dwelling unit density.
- A structure may be built anywhere within the setbacks of the two adjacent structures on the same side of the street, and a corner lot may use the setback of the adjacent lot on each side.
- The total coverage cap counts all impervious surface, buildings and paving together; the building coverage cap is the footprint alone.
A Airport - Every residential use is prohibited in the A district, including one-family, two-family, multifamily, accessory and mobile home dwellings.
- The total coverage cap counts all impervious surface, buildings and paving together; the building coverage cap is the footprint alone.
- The runway protection zone overlay applies over this area as an obstruction and use restriction.
Costs an ADU adds that a house does not
- Septic and water A second dwelling adds bedrooms to the design flow, which on an unsewered parcel often means expanding or replacing the existing system rather than tapping it. This is the single most common reason an ADU budget moves after design, and it is site-specific enough that no model should quote it - get it evaluated early.
- Utility service National Grid territory. A detached unit needs power run to it, and whether it goes on its own meter or subfeeds the main house changes both the cost and the permit path.
- Access and parking Many codes require an added parking space for the accessory unit, and a detached unit usually needs a driveway extension or a path, both of which count against a lot-coverage or impervious-surface cap.
- Short-term rentalsNo local short-term-rental law on record - which is not the same as permission. The Town of Milton has no local short-term rental law, and that is not the same as permission. Confirm with the Building Department before counting on short-term rental income. Separate question from whether you can build the unit.
- Zoning codeecode360.com/9164648
- Building dept(518) 885-9220
Sizing up a specific parcel in Milton?
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Building a full house instead?
A standard-finish house in Milton runs $204–268/sq ft, about $370k–480k at 1,800 sq ft , plus roughly $4,133 for a conforming lot. See what it costs to build a house in Milton.
ADU cost in nearby towns
All Saratoga County towns: Mechanicville (City) · Saratoga Springs (City) · Ballston · Charlton · Clifton Park · Corinth · Day · Edinburg · Galway · Greenfield · Halfmoon · Malta · Moreau · Northumberland · Providence · Saratoga · Stillwater · Waterford · Wilton · Ballston Spa (Village) · Corinth (Village) · Round Lake (Village) · Schuylerville (Village) · South Glens Falls (Village) · Stillwater (Village) · Victory (Village) · Waterford (Village)
More on Milton: Can you build an ADU here? · Zoning for new construction · Saratoga County build cost
ADU cost in Milton: common questions
How much does it cost to build an ADU in Milton, NY?
An 800 sq ft accessory dwelling unit in Town of Milton runs roughly $200k–260k at a standard finish, general-contractor margin included. A 400 sq ft studio runs about $130k–175k. Those are structure costs on an easy site and do not include the septic, water or electrical service work a second unit often triggers.
Why does an ADU cost more per square foot than a house in Milton?
Because a lot of a dwelling's cost is per dwelling, not per square foot. One kitchen, one bath group, one service panel and one heating plant cost about the same in an 800 sq ft cottage as in a 1,800 sq ft house, so on the smaller unit they get spread over less than half the floor area. That is why an ADU here prices at $249–327/sq ft against $204–268/sq ft for a full house, even though it is the same trades doing the same work.
Are ADUs allowed in Milton?
Town of Milton has 9 districts. 8 districts allow ADUs with a special-use permit, 1 does not. Check the specific address with the free ADU checker or confirm with the building department at (518) 885-9220 before you spend money on design.
Can I rent an ADU in Milton short term?
No local short-term-rental law on record - which is not the same as permission for Town of Milton. ADU rules and short-term-rental rules are set separately, so a unit you are allowed to build is not automatically one you are allowed to rent nightly. Confirm both before you underwrite the build on short-term-rental income.
ADU costs are modeled estimates in current 2026 dollars at the Saratoga County regional index, general-contractor margin included, derived from Offsite's cost engine with a stated adjustment for the equipment a dwelling needs one of regardless of size. They are planning numbers for decision-support only - not a bid, quote, or guarantee, and not legal, architectural or engineering advice. They cover the structure and exclude septic expansion, utility service runs, site work beyond a flat and clear pad, and permit fees. ADU eligibility, size, owner-occupancy and permit conditions in the Town of Milton vary by district and often carry exceptions this page does not show; zoning last reviewed 2026-07-31; verify with the building department at (518) 885-9220 before relying on any answer. Sources: the Offsite / Aldo cost engine and zoning dataset.