Maine Building Codes, Permits and Contractor Rules
Here’s every rule from our 50-state guides for Maine on one page: the residential building code, frost depth, retaining wall permits, the 811 dig law, drainage law, contractor licensing, deposit limits, mechanics lien deadlines, workers’ comp, planting zones and frost dates. Each section links the official source and the full 50-state comparison.
Maine at a glance
- Building code: 2021 IRC (some areas only)
- Frost depth: Set locally; often 60 in.
- 811 notice: At least 3 business days but not more than 30 calendar days before excavation
- Contractors: No statewide requirement (local)
- Deposits: 1/3 of price, contracts over $3,000
- Liens: Suit 120 days; sub statement 90 days
- Workers’ comp: 1+ employees
- Drainage rule: Reasonable use
- Planting zones: 3b to 6b
| Topic | Maine | Compare |
|---|---|---|
| Residential building code | 2021 IRC (some areas only) | All states |
| Frost line depth | Set locally; often 60 in. | All states |
| Retaining wall permit | Exempt if not over 4 ft (1219 mm) in height measured from finish grade to the top of the wall, unless supporting a surcharge (Maine replacement of IRC R105.2… | All states |
| 811 notice before digging | At least 3 business days but not more than 30 calendar days before excavation | All states |
| Contractor license | No statewide requirement (local) | All states |
| Deposit limit | 1/3 of price, contracts over $3,000 | All states |
| Right to cancel | 3 business days, sales made at home | All states |
| Lien filing deadline | Suit 120 days; sub statement 90 days | All states |
| Workers’ comp required | 1+ employees | All states |
| Drainage between neighbors | Reasonable use | All states |
| Planting zones (2023 USDA) | 3b to 6b | All states |
| Frost dates (NOAA) | Last frost late Apr (Portland) to early May (Caribou); first frost early Oct (Caribou) to mid-Oct (Augusta) | All states |
Maine residential building code
- Code
- 2021 International Residential Code with Maine amendments (Maine Uniform Building and Energy Code, MUBEC)
- How it applies
- Statewide for some areas only
- In effect since
- April 7, 2025
- Code agency
- Maine Office of Community Affairs, Division of Building Codes and Standards
- Who enforces it
- Must be enforced in towns with more than 4,000 residents. Smaller towns may choose to enforce it but cannot adopt any other building code.
- Good to know
- Maine's code is required in towns of more than 4,000 people. In smaller towns, ask the town office whether it enforces the code.
Compare building codes in all 50 states
Frost line depth in Maine
- Who sets it
- Local building department
- Local examples
- City of Bangor: 60 in. (5 ft, listed under IBC base climate data)
Town of Winslow: 60 in. (5 ft) - Typical range
- 60 in. in both towns listed
Frost line depth in every state
Retaining wall permits in Maine
- Permit exemption
- Exempt if not over 4 ft (1219 mm) in height measured from finish grade to the top of the wall, unless supporting a surcharge (Maine replacement of IRC R105.2 item 3, 16-642 CMR ch. 5). Municipalities may add exemptions by ordinance.
- Who decides
- Your municipal code office decides. Permits are required only where a municipal ordinance requires them.
- Good to know
- Maine measures height from finish grade, not the bottom of the footing. Permits are needed only where a municipal ordinance requires them.
Retaining wall permit rules in every state
811 dig law in Maine
- One-call center
- Dig Safe System, Inc.
- Notice before digging
- At least 3 business days but not more than 30 calendar days before excavation
- Ticket good for
- Work must begin within 30 days of notice; re-notify if not finished within 60 calendar days
- Hand-dig zone
- 18 in. of any marked facility (no mechanical excavation until exposed)
- Homeowners
- Hand digging is not covered: 'excavation' means moving earth with power tools, power equipment or explosives. Tilling, gardening and agricultural earth-moving are excluded. Anyone using power equipment, including homeowners, must notify. Dig Safe states that law requires 'professionals and property owners' to notify, and that private owners must locate their own private lines.
- The law
- 23 M.R.S. § 3360-A
- Good to know
- Marks identify a strip not more than 1.5 ft each side of the facility (36 in. each side for private-owner facilities). Dig Safe describes the notice as 72 hours, not counting weekends and holidays.
Drainage law and stormwater permits in Maine
- Rule
- Reasonable use
- The rule
- Reasonable use by statute: unreasonable use of land that alters the flow of surface water and unreasonably injures another's land, or unreasonably interferes with its reasonable use, is a nuisance (17 M.R.S. 2808, enacted 2005). Before the statute, Maine's common-law rule let owners control surface water on their own land, with liability mainly for artificial collection and discharge. (Label assigned from the statute's reasonableness test.)
- Leading case
- Johnson v. Whitten (pre-statute common-law rule). 384 A.2d 698 (Me. 1978); current rule set by 17 M.R.S. 2808
- What it means for your yard
- If you regrade, add downspouts or build a patio in an unreasonable way that changes runoff and unreasonably harms a neighbor's land, Maine law treats it as a nuisance; a claim must be brought within 3 years.
- State statute
- 17 M.R.S. 2808 (Alteration of surface water flow) makes unreasonable alteration of surface water flow that unreasonably injures another's land a nuisance; actions must be commenced within 3 years after the cause of action accrues.
- Construction stormwater permit
- Maine Department of Environmental Protection (DEP), Bureau of Water Quality / Land Resources: 1 acre or more of disturbed area, or less if part of a common plan that will disturb 1 acre or more: 2024 Maine Construction General Permit (effective Jan. 14, 2025 to Jan. 13, 2030); the state Stormwater Management Law also applies to projects of 1 acre or more of disturbed area in organized areas (with exemptions)
- State rules below 1 acre
- Maine's Erosion and Sedimentation Control Law applies to anyone who conducts an activity involving filling, displacing or exposing earthen materials, with no size threshold stated by DEP and no permit required; erosion controls are required on all such work.
- Local rules
- Maine towns often regulate grading and stormwater through shoreland zoning and site plan ordinances.
- Good to know
- Maine law treats unreasonable changes to surface water flow that harm a neighbor as a nuisance, with a 3-year deadline to sue. Erosion controls are required on any soil disturbance, and the state stormwater law applies at 1 acre.
Contractor licensing in Maine
- Statewide rule
- No statewide requirement (local)
- Who needs it
- Maine does not license or regulate home contractors.
Contractor license requirements in every state
Contractor deposits and your right to cancel in Maine
- Deposit limit
- Initial down payment limited to no more than one-third of the total contract price (10 M.R.S. § 1487(5)).
- Who it covers
- Home construction contracts over $3,000 in materials or labor for building, improving or repairing a residence (10 M.R.S. §§ 1486–1487).
- Right to cancel
- Consumer Solicitation Sales (seller-initiated sales away from the seller's place of business): 3 business days to cancel, and work on items to be affixed to the home cannot begin until the 3 days pass (32 M.R.S. §§ 4661–4671).
- Written contract
- Required for home construction contracts over $3,000, signed by both parties before work begins. Must include names and contact information, property location, estimated start and substantial completion dates, total price, payment method with the one-third down payment limit, description of work and materials, warranty statement, dispute-resolution options, change-order statement, any solicitation-sale cancel rights, and the Attorney General's consumer information (10 M.R.S. § 1487). Change orders must be written and signed (§ 1488).
- Other protections
- Door-to-door home repair sellers (driveways, pools, landscaping, etc.) must be licensed as transient sellers of home repair services (32 M.R.S. §§ 14501–14513). Violations of the home construction contract law are prima facie violations of the Unfair Trade Practices Act (10 M.R.S. § 1490).
- The law
- 10 M.R.S. ch. 219-A, §§ 1486–1490 (Home Construction Contracts); 32 M.R.S. §§ 4661–4671 (Consumer Solicitation Sales)
- Good to know
- Maine caps the down payment at one-third of the price on home construction and repair contracts over $3,000, and the contract has to be in writing before work starts.
Contractor deposit limits in every state
Mechanics lien deadlines in Maine
- Lien deadline (prime)
- No lien statement is required for work under a contract with the owner; the lien is preserved by filing suit within 120 days after the last labor, services or materials (10 M.R.S. §§ 3253(2), 3255(1)).
- Lien deadline (sub/supplier)
- File a sworn statement with the registry of deeds within 90 days after last furnishing and mail the owner a copy (10 M.R.S. § 3253(1)); then sue within 120 days after last furnishing (§ 3255(1)).
- Preliminary notice (sub/supplier)
- Not required. An optional written notice to the owner (with the statutory warning at the top) cuts off the owner's payment defense for later payments (10 M.R.S. § 3255(3)).
- Notice of intent
- Not required.
- Enforce within
- Action in Superior or District Court within 120 days after last furnishing (10 M.R.S. § 3255(1)). Where there's no contract with the owner, the complaint can't be served on the owner until 30 days after filing.
- Homeowner rules
- When the claimant had no contract with the owner, the lien is limited to what the owner still owed its contractor, counting only payments made before the claimant sued or gave written notice (10 M.R.S. § 3255(3)).
- The law
- 10 M.R.S. Ch. 603 (Mechanics' Liens), §§ 3251-3269
- Good to know
- In Maine, a contractor's lien is preserved only by filing a lawsuit within 120 days after the last work. Subs must also record a lien statement within 90 days.
Mechanics lien deadlines in every state
Workers' comp requirements in Maine
- Who must carry it
- Almost all public and private employers with employees must carry coverage; employers of domestic servants in a private home are exempt, and farm/aquaculture employers have conditional exemptions (39-A M.R.S.; Maine Bureau of Insurance employer guide). No separate construction threshold.
- Owners and officers
- Sole proprietors need not cover themselves; LLC owners are not required to be covered and need no waiver; a bona fide owner of at least 20% of a corporation's voting stock may waive coverage in writing; a parent, spouse or child of a sole proprietor, partner or 20% owner may waive in writing (Maine Bureau of Insurance employer guide).
- Subcontractors
- Maine has no general rule making a hiring business liable for an uninsured contractor's crew; the statute's express rule covers landowners contracting for wood harvesting, who are liable unless they get a predetermination, certificate of independent status or certificate of insurance (39-A M.R.S. § 401(4)). If you don't get a contractor's certificate of coverage or a WCB-266 predetermination of independent-contractor status, your insurer might count the contractor's employees as yours and include their payroll in your premium (Maine Bureau of Insurance employer guide).
- Homeowners
- Employers of domestic servants in a private home are exempt from the coverage requirement (Maine Bureau of Insurance employer guide).
- Penalties
- Uninsured employers can be sued by injured workers, are guilty of a Class D crime for a knowing violation, face a civil penalty of up to $10,000 or 108% of the premium that should have been paid, whichever is larger, and in some cases can have a professional license suspended or revoked or the company administratively dissolved (39-A M.R.S. § 324(3); Maine Bureau of Insurance employer guide).
- The law
- 39-A M.R.S. (Maine Workers' Compensation Act of 1992); § 401 (coverage requirement), § 324 (penalties)
- State agency
- Maine Workers' Compensation Board; Maine Bureau of Insurance
- Good to know
- Maine requires coverage for nearly every employer with employees. Ask subcontractors for a certificate of coverage, or your insurer may bill you for their workers.
Workers' comp requirements in every state
Planting zones in Maine
- 2023 USDA zones
- 3b to 6b
- Coldest-night range
- −35°F to 0°F
- Warmest area
- A small midcoast pocket on the St. George peninsula
- Example cities
- Portland: 6a, Augusta: 5b, Bangor: 5a, Fort Kent: 4b
- Local plant advice
- University of Maine Cooperative Extension
- Good to know
- Most of Maine moved up at least a half zone in 2023: the entire coast from York to Washington County is now zone 6, and much of the interior moved from zone 4 to zone 5.
Frost dates in Maine
| Station | Last spring frost | First fall frost | Frost-free days |
|---|---|---|---|
| Portland Southern coast | April 26 | October 15 | 170 |
| Augusta Central Maine | April 27 | October 16 | 172 |
| Bangor Penobscot valley | May 4 | October 4 | 152 |
| Caribou Northern Maine (Aroostook County) | May 7 | October 1 | 143 |
- Typical range
- Last frost late Apr (Portland) to early May (Caribou); first frost early Oct (Caribou) to mid-Oct (Augusta)
- Good to know
- These are typical (50%) dates from NOAA's 1991–2020 climate normals, so about half of years still bring a 32°F night after the listed spring date. In Maine, the last spring frost at the stations listed ranges from late April around Portland to early May around Caribou.
- Local frost or planting guide
- University of Maine Cooperative Extension
Frequently Asked Questions
What building code does Maine use?
2021 International Residential Code with Maine amendments (Maine Uniform Building and Energy Code, MUBEC). It applies as follows: statewide for some areas only. Your local building department can confirm the edition and amendments for your address.
How deep is the frost line in Maine?
Frost depth is set by local building departments. Typical local values: 60 in. in both towns listed. Footings for houses, additions and attached decks go below it.
How much can a contractor ask for up front in Maine?
Initial down payment limited to no more than one-third of the total contract price (10 M.R.S. § 1487(5)). Cancel rights: Consumer Solicitation Sales (seller-initiated sales away from the seller’s place of business): 3 business days to cancel, and work on items to be affixed to the home cannot begin until the 3 days pass (32 M.R.S. §§ 4661–4671).
How long does a contractor have to file a mechanics lien in Maine?
No lien statement is required for work under a contract with the owner; the lien is preserved by filing suit within 120 days after the last labor, services or materials (10 M.R.S. §§ 3253(2), 3255(1)). Subcontractors and suppliers may have different notice rules; see the section above.
What planting zone is Maine?
On the 2023 USDA map, Maine runs from zone 3b to 6b. Examples: Portland 6a, Augusta 5b, Bangor 5a. Enter your ZIP on the USDA map for your exact zone.
Do contractors need workers' comp in Maine?
Almost all public and private employers with employees must carry coverage; employers of domestic servants in a private home are exempt, and farm/aquaculture employers have conditional exemptions (39-A M.R.S.; Maine Bureau of Insurance employer guide). No separate construction threshold. Owner exemptions and subcontractor rules are in the workers’ comp section above.
When is the last frost in Maine?
At the NOAA stations we list: Last frost late Apr (Portland) to early May (Caribou); first frost early Oct (Caribou) to mid-Oct (Augusta). These are typical (50%) dates from the 1991–2020 climate normals, so about half of years still bring a 32°F night after the spring date.
This page is general information, not legal or tax advice. Rules change; the agencies and statutes linked above have the final word.
Maine in each 50-state guide: Frost line depth · 811 dig laws · Retaining wall permits · Contractor licensing · Contractor deposit limits · Building codes · Planting zones · Mechanics lien deadlines · Workers' comp · Frost dates · Drainage laws · Noxious weed laws · Rainfall and snowfall · Landscaper pay · Pesticide applicator licensing · Landscaping sales tax · All state guides
Last checked October 31 and November 1, 2026 against official state and local sources for this state. Rules change; your state agency or local building department has the final word. Spot something out of date? Email info@muthlerlandscaping.com and we’ll fix it.
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Cite as: Muthler Landscaping & Construction, “Maine Building Codes, Permits and Contractor Rules,” https://muthlerlandscaping.com/state-guides/maine/ (last checked November 9, 2026).
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