Michigan Building Codes, Permits and Contractor Rules
Here’s every rule from our 50-state guides for Michigan 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.
Michigan at a glance
- Building code: 2021 IRC (statewide)
- Frost depth: 42 in. statewide
- 811 notice: At least 72 business hours (3 business days, 7 a.m.-5 p.m.) but not more than 14 calendar days before excavation
- Contractors: State license required
- Deposits: No statewide cap
- Liens: 90 days from last furnishing
- Workers’ comp: 3+, or 1 full-time 13+ weeks
- Drainage rule: Civil law (natural flow)
- Planting zones: 4a to 6b
| Topic | Michigan | Compare |
|---|---|---|
| Residential building code | 2021 IRC (statewide) | All states |
| Frost line depth | 42 in. statewide | All states |
| Retaining wall permit | Exempt if not more than 4 ft from bottom of footing to top of wall, unless supporting a surcharge (Mich. Admin. Code R 408.30505, amending IRC R105.2). This is… | All states |
| 811 notice before digging | At least 72 business hours (3 business days, 7 a.m.-5 p.m.) but not more than 14 calendar days before excavation | All states |
| Contractor license | State license required | All states |
| Deposit limit | No statewide cap | All states |
| Right to cancel | 3 business days, sales made at home | All states |
| Lien filing deadline | 90 days from last furnishing | All states |
| Workers’ comp required | 3+, or 1 full-time 13+ weeks | All states |
| Drainage between neighbors | Civil law (natural flow) | All states |
| Planting zones (2023 USDA) | 4a to 6b | All states |
| Frost dates (NOAA) | Last frost mid-Apr (Detroit) to mid-May (Alpena); first frost early Oct (Alpena) to late Oct (Detroit) | All states |
Michigan residential building code
- Code
- 2021 Michigan Residential Code (2021 International Residential Code with Michigan amendments)
- How it applies
- Statewide, mandatory everywhere
- In effect since
- August 29, 2025
- Code agency
- Michigan Department of Licensing and Regulatory Affairs (LARA), Bureau of Construction Codes
- Who enforces it
- Enforced by local, county or state building officials depending on the community; LARA's Bureau of Construction Codes keeps a statewide jurisdiction list.
- Good to know
- Michigan moved to a residential code based on the 2021 IRC on August 29, 2025. Older guides and some web pages still cite the 2015 code.
Compare building codes in all 50 states
Frost line depth in Michigan
- Who sets it
- State code
- Statewide value
- 42 in. statewide
- Good to know
- The 42 in. frost line is set in Mich. Admin. Code R 408.30516 (Table R301.2(1)), effective Aug. 29, 2025.
Frost line depth in every state
Retaining wall permits in Michigan
- Permit exemption
- Exempt if not more than 4 ft from bottom of footing to top of wall, unless supporting a surcharge (Mich. Admin. Code R 408.30505, amending IRC R105.2). This is the wording from the code in effect until Aug. 29, 2025.
- Who decides
- Your local building department decides.
- Good to know
- Michigan's 2021-based code took effect Aug. 29, 2025, and the exemption shown comes from the earlier version. Check with your local building department before you build.
Retaining wall permit rules in every state
811 dig law in Michigan
- One-call center
- MISS DIG 811 (MISS DIG System, Inc.)
- Notice before digging
- At least 72 business hours (3 business days, 7 a.m.-5 p.m.) but not more than 14 calendar days before excavation
- Ticket good for
- 21 days from the start date (180 days if the dig notice says work won't finish in 21 days)
- Hand-dig zone
- 48 in. on either side of the facility marks ('caution zone'); expose by soft excavation
- Homeowners
- MISS DIG says homeowners must call at least 3 business days ahead for 'any project regardless of size or depth.' The statute's 'excavation' definition is limited to power tools or power equipment, so pure hand digging falls outside it. Limited farming exclusions (12 in. in a public right-of-way; 18 in. near pipelines) and fence/sign-post replacement in the same hole.
- The law
- MCL 460.721 et seq. (MISS DIG Underground Facility Damage Prevention and Safety Act, 2013 PA 174)
- Good to know
- MISS DIG 811 says excavation must begin within 14 calendar days of the ticket's dig start date.
Drainage law and stormwater permits in Michigan
- Rule
- Civil law (natural flow)
- The rule
- Natural flow: the lower estate must receive surface water from the upper estate in its natural flow, but the upper owner has no right to increase the amount of water that would naturally flow onto the lower estate. (Label assigned from the rule.)
- Leading case
- Bennett v. County of Eaton (as applied in Kernen v. Homestead Development Co.). Bennett v. Eaton County, 340 Mich. 330 (1954); Kernen v. Homestead Development Co., Mich. Ct. App. No. 205879 (Nov. 17, 1998)
- What it means for your yard
- Your downhill neighbor has to accept natural runoff, but if your regrading, downspouts or patio increase the amount of water reaching them, you can be liable.
- Construction stormwater permit
- Michigan Department of Environment, Great Lakes, and Energy (EGLE); Part 91 SESC permits are issued by County and Municipal Enforcing Agencies: 1 acre or more with a point-source discharge to state waters: construction storm water Permit-by-Rule (requires a Part 91 SESC permit first); 1 to 5 acres automatic, 5 acres or more file a Notice of Coverage
- State rules below 1 acre
- Part 91 soil erosion and sedimentation control (SESC) permit generally required for earth changes of 1 acre or more, or any size within 500 feet of a lake or stream
- Local rules
- Michigan counties and municipal enforcing agencies administer SESC permits and may have stricter local ordinances.
- Good to know
- Michigan requires the lower lot to take natural runoff, but you can't increase the water flowing onto a neighbor. A soil erosion permit is needed for 1 acre or more, or for any earth change within 500 feet of a lake or stream.
Contractor licensing in Michigan
- Statewide rule
- License
- Agency
- Michigan LARA Bureau of Construction Codes (residential builders and maintenance & alteration contractors)
- Who needs it
- Residential builders and maintenance & alteration contractors must be licensed unless the total project price is under $600.
- When it applies
- Single projects of $600 or more (labor + materials)
- Check a contractor
- Official lookup
- Licensed separately
- Electrical, plumbing and mechanical contractors are licensed separately.
- Good to know
- The under-$600 exemption (MCL 339.2403(f)) does not apply if the job is part of a larger operation or split up to avoid the law.
Contractor license requirements in every state
Contractor deposits and your right to cancel in Michigan
- Deposit limit
- No statewide cap.
- Right to cancel
- Home solicitation sales over $25: 3 business days to cancel (Home Solicitation Sales Act, MCL 445.111, 445.113); emergency requests and sales following negotiations at the seller's business are excluded. Home improvement installment (financed) contracts must also let the buyer cancel by 5 p.m. on the business day after signing (Home Improvement Finance Act, MCL 445.1203).
- Written contract
- Home improvement installment contracts must state the contractor's and buyer's names and addresses, the job location, a description of goods and services, the cash price, down payment, amount financed, finance charge, payment schedule and the cancellation notice (MCL 445.1203). No general written-contract rule for cash jobs was confirmed.
- The law
- Home Solicitation Sales Act, MCL 445.111–445.117; Home Improvement Finance Act, MCL 445.1101 et seq. (§ 445.1203)
- Good to know
- If you finance a Michigan home improvement through the contractor, the contract must give you until 5 p.m. the next business day to cancel, on top of the 3-day right for sales made at your home.
Contractor deposit limits in every state
Mechanics lien deadlines in Michigan
- Lien deadline (prime)
- Record the claim of lien with the register of deeds within 90 days after the claimant's last furnishing of labor or material, and serve it on the designee (or owner) within 15 days after recording (MCL 570.1111).
- Lien deadline (sub/supplier)
- Same as prime.
- Preliminary notice (sub/supplier)
- Required. Notice of furnishing to the designee and general contractor named in the notice of commencement (or the owner if no designee) within 20 days after first furnishing. Late notice still protects later work, and earlier work except to the extent the owner already paid the contractor under a sworn statement or lien waiver (MCL 570.1109).
- Notice of intent
- Not required.
- Enforce within
- Foreclosure action within 1 year after the claim of lien was recorded, with a recorded notice of lis pendens (MCL 570.1117).
- Homeowner rules
- A contractor has no lien on a home without a written contract containing the licensing statement (MCL 570.1114). A lien does not attach to a residential structure to the extent the owner has paid the contractor under the contract, if the owner files an affidavit with the court showing the payments (MCL 570.1118a). Owners who pay against a sworn statement or lien waivers are protected against late-noticed sub claims (MCL 570.1109).
- The law
- Construction Lien Act, 1980 PA 497, MCL 570.1101 et seq.
- Good to know
- Michigan subcontractors and suppliers must send a notice of furnishing within 20 days of first working on the job, and contractors need a written contract with the license statement to lien a home. A homeowner who paid the contractor under the contract can keep a lien off the home, to the extent of those payments, by filing an affidavit with the court.
Mechanics lien deadlines in every state
Workers' comp requirements in Michigan
- Who must carry it
- Private employers must carry coverage if they regularly employ 3 or more employees at one time (including part-time), or 1 or more employees for 35+ hours a week for 13+ weeks in the preceding 52 weeks (MCL 418.115; Michigan WDCA). No separate construction threshold.
- Owners and officers
- A sole proprietor is never an employee of the business. Partners, corporate officers and LLC member-managers are employees, but a business can file an exclusion form (WC-337) instead of insuring if every worker is excludable and no subcontractors are used: all partners; all officers owning 10%+ of stock; all member-managers owning 10%+; or a sole proprietor's spouse, child or parent (MCL 418.161, 418.611; WDCA WC-PUB-002, Apr 2026).
- Subcontractors
- A principal that contracts with a contractor who is uninsured (or not subject to the Act) is liable for compensation to the contractor's workers, with indemnity against the contractor; it applies only if the contractor uses workers other than excluded ones (MCL 418.171). Insurers charge premium on uninsured subcontractor payroll.
- Homeowners
- Householders must carry coverage for domestic servants who work 35+ hours a week for 13+ weeks in the preceding 52 weeks (MCL 418.115; Michigan WDCA).
- Penalties
- Failure to comply can result in prosecution and financial penalties (Michigan WDCA; MCL 418.641).
- The law
- MCL 418.101 et seq. (Workers' Disability Compensation Act); §§ 418.115, 418.161, 418.171, 418.611, 418.641
- State agency
- Michigan Department of Labor and Economic Opportunity, Workers' Disability Compensation Agency (WDCA)
- Good to know
- Michigan requires coverage with 3 employees at once, or just 1 who works 35+ hours a week for 13 weeks. A contractor can be liable for an uninsured sub's workers.
Workers' comp requirements in every state
Planting zones in Michigan
- 2023 USDA zones
- 4a to 6b
- Coldest-night range
- −30°F to 0°F
- Coldest area
- Gogebic County and the northwestern Upper Peninsula
- Warmest area
- Detroit area and the southwest Lake Michigan shore
- Example cities
- Detroit: 6b, Grand Rapids: 6a, Lansing: 6a, Marquette: 5b
- Good to know
- The coldest spots, rated 4a, are limited to a few areas of the western Upper Peninsula, mainly Gogebic County. Detroit is 6b, while Grand Rapids and Lansing are 6a.
Frost dates in Michigan
| Station | Last spring frost | First fall frost | Frost-free days |
|---|---|---|---|
| Detroit Southeast Michigan | April 20 | October 27 | 188 |
| Grand Rapids West Michigan | April 29 | October 20 | 174 |
| Alpena Northeast Lower Peninsula | May 17 | October 1 | 136 |
| Sault Ste. Marie Eastern Upper Peninsula | May 9 | October 11 | 151 |
- Typical range
- Last frost mid-Apr (Detroit) to mid-May (Alpena); first frost early Oct (Alpena) to late Oct (Detroit)
- 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 Michigan, the last spring frost at the stations listed ranges from mid-April around Detroit to mid-May around Alpena.
Frequently Asked Questions
What building code does Michigan use?
2021 Michigan Residential Code (2021 International Residential Code with Michigan amendments). It applies as follows: statewide, mandatory everywhere. Your local building department can confirm the edition and amendments for your address.
How deep is the frost line in Michigan?
The state sets 42 in. statewide. Footings for houses, additions and attached decks go below it.
How much can a contractor ask for up front in Michigan?
No statewide cap. Cancel rights: Home solicitation sales over $25: 3 business days to cancel (Home Solicitation Sales Act, MCL 445.111, 445.113); emergency requests and sales following negotiations at the seller’s business are excluded. Home improvement installment (financed) contracts must also let the buyer cancel by 5 p.m. on the business day after signing (Home Improvement Finance Act, MCL 445.1203).
How long does a contractor have to file a mechanics lien in Michigan?
Record the claim of lien with the register of deeds within 90 days after the claimant’s last furnishing of labor or material, and serve it on the designee (or owner) within 15 days after recording (MCL 570.1111). Subcontractors and suppliers may have different notice rules; see the section above.
What planting zone is Michigan?
On the 2023 USDA map, Michigan runs from zone 4a to 6b. Examples: Detroit 6b, Grand Rapids 6a, Lansing 6a. Enter your ZIP on the USDA map for your exact zone.
Do contractors need workers' comp in Michigan?
Private employers must carry coverage if they regularly employ 3 or more employees at one time (including part-time), or 1 or more employees for 35+ hours a week for 13+ weeks in the preceding 52 weeks (MCL 418.115; Michigan WDCA). No separate construction threshold. Owner exemptions and subcontractor rules are in the workers’ comp section above.
When is the last frost in Michigan?
At the NOAA stations we list: Last frost mid-Apr (Detroit) to mid-May (Alpena); first frost early Oct (Alpena) to late Oct (Detroit). 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.
Michigan 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
Soil: Michigan’s most common soils, state soil, and how much ground is wet, clayey or shallow to bedrock by county. Michigan soil types
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, “Michigan Building Codes, Permits and Contractor Rules,” https://muthlerlandscaping.com/state-guides/michigan/ (last checked November 12, 2026).
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