York County · Maine
ADU rules in Saco, ME
Saco is a York County city on the Saco River and the coast.
This is a reference guide. Saco is not on our service-area list, so call to ask whether we can take on a build there.
Town ADU rules
What’s allowed on your lot in Saco.
Saco allows an ADU of 400 to 1,000 sq ft by right where its use tables permit one, with no added parking.
- Size limit
- 400 to 1,000 sq ft of total floor area
- Where it can go
- Attached, within, or detached from a single-family residence
- Owner on site
- No town rule
- Parking
- No added spaces; ADU uses the single-family parking (2 per house)
- Approval
- By right where permitted; building permit or certificate of occupancy from the city
- Rentals
- No rentals shorter than one month
- Water setback
- 75 ft from streams, tributary streams and wetland edges; 100 ft from GPA great ponds and rivers flowing to them
Allowed
- Attached or detachedADUs are an accessory use to a new or existing single-family residence in districts where they are permitted. They may be attached to, within, or detached from the principal residence.§230-701.B
- How manyNo more than one ADU per building lot, attached or detached.§230-701.B
- SizeMaximum 1,000 sq ft and minimum 400 sq ft of total floor area. Must be accessory to a principal residence.§230-701.E(2) [Amended 9-25-2023]
- LotAn authorized ADU is not counted as a second dwelling unit when calculating minimum lot area per dwelling unit under Article IV. New construction for an ADU or the main house must meet all setback, lot coverage and height requirements.§230-701.C, E(1)
- RentalsADUs may not be rented for less than a month.§230-701.D
- ParkingNo additional parking for an ADU; it uses the parking required for the single-family use (2 spaces per dwelling unit for single-family).§230-1001, Table 10-1
- DesignA detached ADU must share the main house's existing driveway and be visually compatible with it (building proportions, exterior materials, fenestration and trim, roof pitch, and other details similar or complementary). ADUs must sit on permanent foundations.§230-701.E(3), (6), (7)
- SepticIf the lot has public sewer, both the house and the ADU must connect to it. The same applies to public water.§230-701.E(8), (9)
- OtherDetached ADUs require sprinkler or other fire suppression systems approved by the Fire Department. Attached or internal ADUs need them only if the existing house already has one.§230-701.E(10)
- ApprovalADU is P (permitted) in Table 3-3 in RC, LDR, SR, WR, MDR, HDR, D, MB, HB and CE. It is not permitted (blank) in GB, SI, PR, BI and I. A building permit or certificate of occupancy is required. The Code Enforcement Office enforces the section.§230-701.F, G; §230-307 Table 3-3
- ShorelandShoreland overlays (Resource Protection Overlay, Shoreland Overlay, Coastal Development Overlay): structures must be set back 75 ft from the normal high-water line of a stream or tributary stream or the upland edge of a wetland, and 100 ft from GPA great ponds and rivers flowing to them. Functionally water-dependent uses: 0 ft. Max height 35 ft. Street frontage is 200 ft in RPOD, and 150 ft (RC/LDR lots) or 100 ft (other lots) in the SLOD and CDOD. Protected water resources include the maximum spring high tide level of tidal waters. In the shoreland zone, lot coverage includes all nonvegetated areas.§230-803, Dimensional Standards for Principal and Accessory Structures in Natural Resource Districts; §230-2103 "Lot coverage"
- State lawThe town text sets a 400 sq ft minimum. Maine law sets the minimum at 190 sq ft.30-A M.R.S. §4364-B(6)
Not allowed
- Not allowedNo second ADU on a lot.§230-701.B
- Not allowedNo ADU rentals of less than one month.§230-701.D
- Not allowedNo ADU in GB, SI, PR, BI or I districts (blank in Table 3-3).§230-307 Table 3-3
- Not allowedA detached ADU may not have its own separate driveway; it must share the existing access drive.§230-701.E(6)
- Not allowedADUs only as accessory to a single-family residence.§230-701.B
Read 2026-11-15 from City of Saco Code, Chapter 230: Zoning (§230-701 Accessory dwelling units; Art. III use tables; Art. IV dimensional standards; Art. VIII shoreland) (§230-701 [Amended 7-25-2022]; E(2) and E(4) amended 9-25-2023; E(5) repealed 9-25-2023. §230-307 amended through 12-16-2024; §230-401 [Amended 3-18-2024]; parking Table 10-1 [Amended 9-25-2023]. eCode360 shows legislation through 08-03-2026; read live 2026-11-15.). Anything not listed here, we check with the Saco land-use office for your lot.
Setbacks
Front, side and rear in Saco.
Maine 30-A M.R.S. §4364-B - at least one ADU with a single-family home; from July 1, 2027, also with a two- or three-unit building, and at least three units per lot
Saco's dimensional table, as printed in the ordinance.
| District | Front | Side | Rear | Lot / cover / height |
|---|---|---|---|---|
| RCprimaryRural Conservation§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. RC frontage 200 ft. RC accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 30 ft min | 25 ft | 25 ft | 40,000 sq ft sewered; 80,000 unsewered (per dwelling unit: 40,000 sewered; 80,000 unsewered) · 20% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 35 ft |
| LDRLow Density Residential§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. LDR frontage 100 ft. LDR accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 30 ft min | 20 ft | 20 ft | 20,000 sq ft sewered; 40,000 unsewered (per dwelling unit: 10,000 sewered; 20,000 unsewered) · 25% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 35 ft |
| SRSeaside Residential§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. SR frontage 75 ft. SR accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 25 ft min | 15 ft | 15 ft | 7,500 sq ft sewered; 40,000 unsewered (per dwelling unit: 7,500 sewered; 20,000 unsewered) · 30% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 35 ft |
| WRWest Residential§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. WR frontage 100 ft. WR accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 25 ft min | 15 ft | 15 ft | 15,000 sq ft sewered; 30,000 unsewered (per dwelling unit: 7,500 sewered; 15,000 unsewered) · 25% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 35 ft |
| MDRMedium Density Residential§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. MDR frontage 75 ft. MDR accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 25 ft min | 10 ft | 10 ft | 7,500 sq ft sewered; 20,000 unsewered (per dwelling unit: 5,000 sewered; 17,500 unsewered) · 35% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 35 ft |
| HDRHigh Density Residential§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. HDR frontage 75 ft. HDR accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 5 ft min; 15 ft max | 10 ft | 10 ft | 6,000 sq ft sewered; n/a unsewered (per dwelling unit: 3,000 sewered; n/a unsewered) · 45% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 50 ft |
| DDowntown§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. D frontage 30 ft. D accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 0 ft min; 10 ft max | 10/0 ft (0 ft for party/shared wall) | 10/0 ft (0 ft for party/shared wall) | 2,000 sq ft sewered; n/a unsewered (per dwelling unit: 1,500 sewered; n/a unsewered) · 100% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 60 ft (35 ft minimum height does not apply to single- or two-family dwellings) |
| MBMain and Beach§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. MB frontage 75 ft. MB accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 5 ft min; 25 ft max | 10 ft | 10 ft | 6,000 sq ft sewered; n/a unsewered (per dwelling unit: 3,000 sewered; n/a unsewered) · 40% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 35 ft |
| HBHighway Business§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. HB frontage 100 ft. HB accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 15 ft min | 10 ft | 10 ft | 7,500 sq ft sewered; 20,000 unsewered (per dwelling unit: 4,000 sewered; 17,500 unsewered) · 50% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 50 ft |
| CECamp Ellis§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. CE frontage 50 ft. CE accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 15 ft min | 10 ft | 10 ft | 7,500 sq ft sewered; n/a unsewered (per dwelling unit: 7,500 sewered; n/a unsewered) · 40% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 35 ft |
| PRPortland Road§230-401, Table 4-1 Dimensional Standards for All Zoning Districts [Amended 3-18-2024]; uses from §230-307 Table 3-3. PR frontage 200/50 ft (200 ft on Route 1; 50 ft other roads). PR accessory buildings: Sheds under 120 sq ft without electricity: 5 ft side/rear, max 12 ft any dimension, one per lot, not forward of the house front wall (§230-406). | 40/25 ft (40 ft on Route 1, Cascade Rd, Flag Pond Rd; 25 ft other roads) | 20 ft | 20 ft | 20,000 sq ft sewered; 20,000 unsewered (per dwelling unit: 7,500 sewered; 30,000 unsewered) · 60% (lot area covered by principal and accessory structures; in shoreland zone also nonvegetated areas) · Height 60 ft |
Verified 2026-11-15 against City of Saco Code, Chapter 230: Zoning (§230-701 Accessory dwelling units; Art. III use tables; Art. IV dimensional standards; Art. VIII shoreland). Towns amend ordinances, so confirm with the land-use office before you build. Official source
FAQ
ADUs in Saco.
- How big can an ADU be in Saco?
- 400 to 1,000 sq ft of total floor area, per §230-701.E(2) [Amended 9-25-2023] as read 2026-11-15.
- Does the owner have to live on the lot in Saco?
- No town rule (City of Saco Code, Chapter 230: Zoning (§230-701 Accessory dwelling units; Art. III use tables; Art. IV dimensional standards; Art. VIII shoreland)).
- Can an ADU in Saco be detached?
- Attached, within, or detached from a single-family residence, under §230-701.B.
Planning an ADU in Saco?
Call (978) 987-0089 and we will say whether we can build there. See the ADU models