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.
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 District (the Town's standard residential district: minimum lot 0.5 acre, 100 ft lot width, 20% maximum structure coverage, 50% maximum impervious surface, 35 ft height, 50 ft front yard, 20 ft side, 50 ft rear. MILTON STATES BOTH A DENSITY AND A MINIMUM LOT AREA AND THE DENSITY IS USUALLY THE BINDING ONE: maximum density is 1 DWELLING UNIT PER ACRE WITHOUT sewer and water, rising to 2 PER ACRE WITH both. Schedule note 3 says so directly — 'actual lot area may be significantly larger based on the maximum dwelling unit density' — so on an unserviced parcel the half-acre minimum lot is unreachable in practice, because one unit per acre governs. Read the two figures together, never the lot minimum alone. CONTEXTUAL SETBACK RELIEF (note 5): notwithstanding the stated setbacks, a structure in the RESIDENTIAL districts 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 — so on a built-up street the neighbours, not the 50 ft figure, set the building line. MILTON STATES TWO REAL MAXIMUMS, NOT AN INVERSE STANDARD: 'Maximum structure coverage' and 'Maximum impervious surface' are both genuine caps. maxLotCoverage stores STRUCTURE coverage; the impervious cap is the one that usually binds a suburban lot, because 20% structure against 50% impervious leaves only 30% for drives, walks and patios.) | 0.5 ac | 50 / 20 / 50 ft | 35 ft | Special permit |
| R2 Rural District (the Town's large-lot rural district and the one where lot size and density diverge most sharply: minimum lot 5 ACRES, 200 ft lot width, 10% maximum structure coverage, 25% maximum impervious surface, 35 ft height, and the deepest yards in Milton at 150 FT FRONT, 50 ft side and 75 ft rear. MAXIMUM DENSITY IS 0.2 DWELLING UNITS PER ACRE — one unit per five acres — WITHOUT sewer and water, and the with-utilities column is 'X', meaning NO INCREASED DENSITY IS AVAILABLE EVEN WHERE SERVICE EXISTS. Bringing water and sewer to an R2 parcel buys nothing in yield, which is unusual and worth knowing before paying for extension. THE OPEN SPACE INCENTIVE OPTION IS THE ONLY WAY TO DO BETTER and it is recorded as a separate R2os entry: under § 180-30 it cuts the minimum lot from 5 acres to 1 acre and the Planning Board may grant a density bonus of UP TO 50% above the maximum density. On a rural parcel that is the difference between 20 units and 30 on 100 acres, and between 5-acre lots and 1-acre lots — by a wide margin the most consequential entitlement in the Town. Both coverage figures are genuine maximums; the 10% structure and 25% impervious caps are the tightest in Milton outside the Airport district. Bed-and-breakfast home is PERMITTED BY RIGHT in R2, the only district besides the two hamlets where that is true.) | 5 ac | 150 / 50 / 75 ft | 35 ft | Special permit |
| R2 Rural District — Open Space Incentive Option (NOT a separately mapped district but a distinct standard set that § 180-86 gives its own column, applying where an R2 subdivision takes the § 180-30 open space incentive. It is the single most consequential entitlement in Milton: THE MINIMUM LOT DROPS FROM 5 ACRES TO 1 ACRE and the front yard from 150 ft to 50 ft, while lot width falls from 200 ft to 100 ft and the side yard from 50 ft to 20 ft. Structure coverage stays at 10% and impervious at 25%; height stays 35 ft; the REAR yard stays at 75 ft. THE DENSITY BONUS IS THE SECOND HALF OF THE DEAL: base density remains 0.2 dwelling units per acre (one per five acres), but schedule note 1 lets the PLANNING BOARD GRANT A BONUS OF UP TO 50% ABOVE THAT MAXIMUM under § 180-30 — so a 100-acre parcel that yields 20 units conventionally can reach 30. THE PRICE IS A PERIMETER SETBACK THAT IS EASY TO MISS AND CAN STERILISE A NARROW PARCEL: schedule note 6 requires the BUILDING AREA of new lots created under the open space incentive to sit at least 150 FEET from all adjacent properties that are not part of the open space subdivision AND from all preexisting Town, county and state roads. On a 300-foot-wide parcel that 150 ft ring leaves nothing, so test the perimeter before assuming the incentive is usable. Model both the conventional R2 layout and this one — the answer is parcel-shape dependent, not obvious.) | 1 ac | 50 / 20 / 75 ft | 35 ft | Special permit |
| TC Town Center District (Milton's densest and most urban district, and the only one with no minimum lot area, no minimum lot width and no side yard at all — the schedule prints 'X' for all three, which is the correct record of a town-centre form and must not be back-filled. Maximum structure coverage 75%, maximum impervious surface 90%, both the highest in the Town alongside CMU. MAXIMUM STRUCTURE HEIGHT IS 50 FT, the tallest in Milton against 35 ft everywhere else. THE FRONT YARD IS A BUILD-TO BAND, NOT A FLOOR: 10 FT MINIMUM WITH A 15 FT MAXIMUM — TC is the only Milton district with a maximum front yard, so a building cannot be set back beyond 15 ft. Schedule note 7 provides the sole relief: where a utility easement prevents building to the prescribed setback, the structure goes as close to the street line as possible. Rear yard 20 ft. DENSITY IS 16 DWELLING UNITS PER ACRE WITH sewer and water and only 1 without, so TC is functionally a serviced-land district; note 2 cautions that the 16 is an INTENDED maximum for an apartment building and actual density may be significantly less after site plan review, including consideration of compatibility with residential abutters — treat 16 as a ceiling to argue for, not an entitlement. GROUND-FLOOR RESTRICTION (note 3): all buildings fronting GEYSER ROAD and/or ROWLAND STREET within the Town Center have apartments restricted to UPPER FLOORS ABOVE MANDATORY FIRST-FLOOR COMMERCIAL USES, except that the Planning Board may allow first-floor apartments at the back, not facing the roadways. Design and maintenance standards for this district are in § 180-39.4 and the Town Center Design Guidelines are Attachment 2. One- and two-family dwellings are PROHIBITED in TC — multifamily is the residential form here.) | — | 10 / - / 20 ft | 50 ft | Special permit |
| MU Mixed Use District (minimum lot 0.25 acre, 75 ft lot width, 50% maximum structure coverage, 75% maximum impervious surface, 35 ft height, 30 ft front yard, 25 ft side, 30 ft rear. Density is 1 dwelling unit per acre without sewer and water and 16 PER ACRE WITH both — the same sixteenfold step as the Town Center and Corridor Mixed Use, which makes utility service the single largest determinant of value on an MU parcel. THE SIDE YARD IS THE ODDITY AND IS EASY TO READ PAST: at 25 FT it is the deepest side yard of any non-rural district in Milton, deeper than the 12 ft required in CMU and both hamlets and deeper than the 20 ft in R1 — on a 75-foot-wide lot, two 25 ft side yards leave a 25-foot building envelope, so lot width, not coverage, is what actually limits a narrow MU site. MU is the most residentially permissive of the mixed districts: the one-family dwelling and multifamily dwelling are both PERMITTED BY RIGHT and the two-family dwelling is permitted as well, where TC and CMU prohibit one- and two-family entirely. Both coverage figures are genuine maximums.) | 0.25 ac | 30 / 25 / 30 ft | 35 ft | Special permit |
| CMU Corridor Mixed Use District (the Route 50 corridor. NAMING CONFLICT FLAGGED FOR THE TOWN: § 180-6, amended 10-1-2014 by L.L. No. 2-2014, enumerates this district as 'CT Commercial Transition District', but BOTH schedules — § 180-86 Area and Bulk and § 180-87 Use — head the column 'CMU', and use-schedule note 4 spells it out as 'Corridor Mixed Use'. The schedules carry the standards and are the later, more specific statement, so CMU is used here; the Town should reconcile § 180-6. Minimum lot 0.25 acre, 50 ft lot width, 75% maximum structure coverage and 90% maximum impervious surface (tied with TC for the highest in Milton), 12 ft side yard, 25 ft rear. THE FRONT YARD IS 75 FT — the second deepest in the Town after R2's 150 ft, and startling for a district with a quarter-acre minimum lot and a 75% coverage allowance. That deep highway setback, not the coverage figure, is what shapes a Route 50 site. HEIGHT IS ROAD-DEPENDENT (note 4 to the bulk schedule): 35 FT for buildings FRONTING ROUTE 50, but buildings SET BACK 75 FEET OR MORE from Route 50 may go to 50 FT — so the deep setback buys fifteen feet of height. 35 ft is recorded as the base. GROUND-FLOOR RESTRICTION (use-schedule note 4): all mixed-use buildings directly fronting Route 50 have residential restricted to upper floors above first-floor commercial, except that the Planning Board may allow residential at the back and side provided it does not directly face Route 50; residential IS permitted on the first floor and upper levels where the building does not front Route 50 or is set back more than 75 ft. Note 5 states a target mix of 70% commercial to 30% residential, adjustable at Planning Board discretion. Density 1 du/acre without utilities, 16 with. One- and two-family dwellings are prohibited; multifamily is permitted. CMU IS THE ONLY MILTON DISTRICT WHERE AN ACCESSORY DWELLING IS PERMITTED BY RIGHT rather than by special permit.) | 0.25 ac | 75 / 12 / 25 ft | 35 ft | Special permit |
| H1 Rock City Falls Hamlet District (one of Milton's two hamlet districts, dimensionally identical to H2 West Milton: minimum lot 1 acre, 50 ft lot width, 40% maximum structure coverage, 60% maximum impervious surface, 35 ft height, 15 ft front yard, 12 ft side, 50 ft rear. The hamlet form shows in the pairing of a SHALLOW 15 FT FRONT YARD with a DEEP 50 FT REAR YARD — buildings sit close to the street with the depth kept behind them, which is what preserves a hamlet streetscape. Density is 1 dwelling unit per acre without sewer and water and 3 PER ACRE WITH both: a real but modest step, far below the sixteenfold jump in TC, MU and CMU, which is deliberate — the hamlets are meant to stay hamlets. Note the tension between the 1-acre minimum lot and the 50 ft minimum width: a one-acre lot only 50 ft wide would be over 870 ft deep, so in practice the acre governs and the width figure exists to permit narrow legacy hamlet lots. One- and two-family dwellings are available (one-family by right, two-family by special permit) and BED-AND-BREAKFAST HOME IS PERMITTED BY RIGHT, as it is in H2 and R2 — the hamlets are where Milton's small-lodging activity is meant to sit. Both coverage figures are genuine maximums.) | 1 ac | 15 / 12 / 50 ft | 35 ft | Special permit |
| H2 West Milton Hamlet District (Milton's second hamlet district, DIMENSIONALLY IDENTICAL TO H1 ROCK CITY FALLS IN EVERY RESPECT — minimum lot 1 acre, 50 ft lot width, 40% maximum structure coverage, 60% maximum impervious surface, 35 ft height, 15 ft front yard, 12 ft side, 50 ft rear, and the same 1 du/acre without utilities rising to 3 per acre with sewer and water. The two hamlets also share an identical use schedule column. That identity is real and deliberate, not a transcription artifact: the districts differ only in where they are mapped, H1 at Rock City Falls and H2 at West Milton. As in H1, the shallow 15 ft front yard against a deep 50 ft rear yard is what produces the hamlet streetscape, the 3 du/acre serviced density is modest by design, and BED-AND-BREAKFAST HOME IS PERMITTED BY RIGHT. Both coverage figures are genuine maximums.) | 1 ac | 15 / 12 / 50 ft | 35 ft | Special permit |
| A Airport District (the district serving the Saratoga County Airport, and THE ONLY MILTON DISTRICT WITH NO RESIDENTIAL ENTITLEMENT OF ANY KIND — both density rows print 'X', the one-family, two-family and multifamily dwelling rows are all prohibited, and the accessory dwelling is prohibited too. Do not underwrite housing here at any lot size. Minimum lot 2 acres and MINIMUM LOT WIDTH 300 FT, by far the widest requirement in the Town against 200 ft in rural R2 and 100 ft or less everywhere else. Maximum structure coverage 20% but maximum impervious surface 75% — THE WIDEST GAP BETWEEN THE TWO FIGURES ANYWHERE IN MILTON, and it is a deliberate accommodation of apron, taxiway and hangar paving: 55 percentage points of the lot may be hard surface that is not building. Height 35 ft. Yards are 75 ft front, 50 ft side, 75 ft rear. THE RUNWAY PROTECTION ZONE OVERLAY (RPZ, § 180-6B(2)) sits on top of this and neighbouring districts and restricts what may be done within it regardless of the underlying district — check whether a parcel falls inside the RPZ before assuming any of these figures govern, because obstruction and use limits there can be decisive.) | 2 ac | 75 / 50 / 75 ft | 35 ft | No |
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. No short-term-rental provision exists in the Town of Milton Zoning Law. Chapter 180 was read in full: § 180-5 defines no short-term rental, vacation rental or transient-occupancy use, the § 180-87 District Schedule of Use Regulations lists none, and there is no registration or licensing requirement anywhere in the chapter. The only enumerated transient-lodging uses are the BED-AND-BREAKFAST HOME and the BED-AND-BREAKFAST ESTABLISHMENT, and Milton treats them as materially different things: the bed-and-breakfast HOME is PERMITTED BY RIGHT in the Rural district and in both hamlet districts (H1 Rock City Falls and H2 West Milton) and is a special permit in R1, TC and MU; the bed-and-breakfast ESTABLISHMENT is a special permit in R1, R2, TC, H1 and H2 and is PROHIBITED in MU and CMU. Both are prohibited in the Airport district. That a bed-and-breakfast home is by-right in three districts is unusual for Saratoga County and is the closest thing Milton has to a permissive short-stay regime — but it is a defined, owner-present lodging use, not a whole-house short-term rental. Recorded 'unknown' rather than 'prohibited' because the Town has never legislated on short-term rental specifically. Absence of a found STR provision is NOT permission. Get a written answer from the Building Department at (518) 885-9220 before underwriting short-term rental income on a Milton parcel. Separately, New York State has required every short-term-rental host to register the unit with the State through the county registry since 2025, regardless of what the municipality allows, and Saratoga County HAS adopted a county-level short-term-rental programme: a 3% occupancy tax and a MANDATORY county registry, covering any room or space in a dwelling let for under 30 consecutive days. Registration runs two years, an unregistered host faces fines of up to $500, and the booking platform is separately liable for processing an unregistered listing — so Airbnb and Vrbo will delist. The City of Saratoga Springs runs its own registry alongside it. Separate question from whether you can build the unit.
- Building dept(518) 885-9220
Sizing up a specific parcel in Milton?
Aldo pulls the exact zoning district, setbacks, and build feasibility for any parcel — before you buy. Enter your email to open Aldo and run your free report.
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: Offsite / Aldo cost engine (costEngine.js + constants.js); zoning dataset (municipalData.js).