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Wisconsin Building Codes, Permits and Contractor Rules

Here’s every rule from our 50-state guides for Wisconsin 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.

Wisconsin at a glance

Building code: Set by cities and counties
Frost depth: 48 in. below adjacent grade (Uniform Dwelling Code, SPS 321.16)
811 notice: At least 3 working days before nonemergency excavation (excluding weekends and legal holidays)
Contractors: License for some trades/amounts only
Deposits: No statewide cap
Liens: 6 months from last furnishing
Workers’ comp: 3+, or $500 wages in a quarter
Drainage rule: Reasonable use
Planting zones: 3b to 6a

Topic	Wisconsin	Compare
Residential building code	Set by cities and counties	All states
Frost line depth	48 in. below adjacent grade (Uniform Dwelling Code, SPS 321.16)	All states
Retaining wall permit	Set locally. The Uniform Dwelling Code covers new one- and two-family dwellings and doesn't regulate retaining walls; municipalities may regulate structures…	All states
811 notice before digging	At least 3 working days before nonemergency excavation (excluding weekends and legal holidays)	All states
Contractor license	License for some trades/amounts only	All states
Deposit limit	No statewide cap	All states
Right to cancel	3 business days, sales made at home	All states
Lien filing deadline	6 months from last furnishing	All states
Workers’ comp required	3+, or $500 wages in a quarter	All states
Drainage between neighbors	Reasonable use	All states
Planting zones (2023 USDA)	3b to 6a	All states
Frost dates (NOAA)	Last frost mid-Apr (Milwaukee) to late May (Rhinelander); first frost late Sep (Rhinelander) to late Oct (Milwaukee)	All states

Summary for Wisconsin. Details, exceptions and official sources are in each section below.

Wisconsin residential building code

Code: Wisconsin Uniform Dwelling Code (Wis. Admin. Code SPS 320-325), the state's own code, not the IRC
How it applies: Statewide, mandatory everywhere
Code agency: Wisconsin Department of Safety and Professional Services (DSPS)
Who enforces it: Applies to one- and two-family homes built since June 1, 1980. Municipalities with delegated authority issue permits and inspect; elsewhere a DSPS-appointed county inspector does. Local rules may not be stricter or looser than the UDC.
Good to know: Wisconsin uses its own Uniform Dwelling Code instead of the IRC, so some IRC-based guidance may not match Wisconsin rules. Deck, stair and footing details should be checked against the UDC.

Compare building codes in all 50 states

Frost line depth in Wisconsin

Who sets it: State code
Statewide value: 48 in. below adjacent grade (Uniform Dwelling Code, SPS 321.16)
Good to know: Wisconsin's Uniform Dwelling Code applies statewide to one- and two-family homes and requires footings and foundations at least 48 in. below adjacent grade. Ask your building inspector about exceptions such as frost-protected shallow foundations.

Frost line depth in every state

Retaining wall permits in Wisconsin

Permit exemption: Set locally. The Uniform Dwelling Code covers new one- and two-family dwellings and doesn't regulate retaining walls; municipalities may regulate structures outside its scope (detached buildings, fences, driveways and the like) by local ordinance (SPS 320.02(2)(c), per DSPS's UDC commentary).
Who decides: Your city, village, town or county decides under its own ordinances.
Good to know: Wisconsin's Uniform Dwelling Code doesn't cover retaining walls, but your city, village, town or county may regulate them by local ordinance.

Retaining wall permit rules in every state

811 dig law in Wisconsin

One-call center: Diggers Hotline, Inc.
Notice before digging: At least 3 working days before nonemergency excavation (excluding weekends and legal holidays)
Ticket good for: No fixed expiration: marks valid for the length of the project if maintained
Hand-dig zone: 18 in. minimum clearance between the marking of an unexposed transmission facility and power-operated equipment
Homeowners: Yes. 'Excavation' has no homeowner, hand-tool, depth or gardening exclusion in Wis. Stat. 182.0175; Diggers Hotline: 'Homeowners should request a utility locate for any project that requires digging.'
The law: Wis. Stat. § 182.0175
Good to know: A new notice is required if excavation doesn't begin within 10 days of the scheduled start or stops for more than 10 days. Diggers Hotline recommends allowing 4 business days and accepts start dates up to 30 days out.

811 dig laws in every state

Drainage law and stormwater permits in Wisconsin

Rule: Reasonable use
The rule: Reasonable use: Wisconsin rejected the common enemy doctrine and adopted the Restatement of Torts reasonable use rule; liability depends on whether the invasion is unreasonable.
Leading case: State v. Deetz. 66 Wis. 2d 1, 224 N.W.2d 407 (1974)
What it means for your yard: If your regrading, downspouts or patio unreasonably send water onto a neighbor, you can be liable; courts weigh the reasonableness of the change.
Construction stormwater permit: Wisconsin Department of Natural Resources (DNR): 1 or more acres of land disturbance (WPDES Construction Site Storm Water Discharge Permit)
State rules below 1 acre: Erosion and sediment control practices are required at one- and two-family dwelling construction sites under the state Uniform Dwelling Code (SPS 321.125), with erosion control measures shown on the plan submitted with the UDC permit application (SPS 320.09); the Department of Safety and Professional Services administers these rules for sites under 1 acre, and DNR has sole jurisdiction at 1 acre or more (DSPS history of Wisconsin's soil erosion program, rev. 3/2016).
Local rules: Wisconsin counties and municipalities commonly have construction site erosion control and stormwater ordinances that apply to smaller projects.
Good to know: Wisconsin uses a reasonable-use test for drainage disputes between neighbors. State construction site stormwater permits start at 1 acre.

Drainage laws in every state

Contractor licensing in Wisconsin

Statewide rule: License for some trades/amounts only
Agency: Wisconsin Department of Safety and Professional Services (DSPS)
Who needs it: Contracting businesses need a Dwelling Contractor certification to obtain building permits on one- and two-family homes; there does not appear to be a general home improvement license.
When it applies: Needed to obtain building permits for one- and two-family dwellings
Check a contractor: Official lookup
Good to know: The Dwelling Contractor certification applies when a building permit is pulled for a one- or two-family home. DSPS does not list a license for home improvement work that doesn't need a permit.

Contractor license requirements in every state

Contractor deposits and your right to cancel in Wisconsin

Deposit limit: No statewide cap. If any payment is due before the work is complete, the contract must be in writing (Wis. Admin. Code ATCP 110.05).
Right to cancel: Home solicitation sales over $25 (face-to-face, phone or mail solicitation away from the seller's usual place of business): 3 business days to cancel, excluding weekends and holidays (Wis. Stat. §§ 423.201, 423.202). Separately, if you paid in advance and the contractor misses a contract deadline (or doesn't give notice of a delay and get your agreement to a new deadline), you may cancel by written notice and demand your unspent payments, which the contractor must refund within 15 days, plus a written accounting within 30 days (ATCP 110.07).
Written contract: Required whenever any payment is due before the work is complete. Must be signed by all parties and state all material terms, including the total price with finance charges (or hourly labor rate for time-and-materials) and the dates or period for starting and completing the work; the buyer gets a copy before work begins or any payment is made (ATCP 110.05). The contractor must also give the 'Notice of Consumer's Right to Receive Lien Waivers' before signing (ATCP 110.025).
Other protections: Refund of unspent prepayments within 15 days when a contractor misses deadlines (ATCP 110.07). Sellers may not demand final payment before the job is completed (ATCP 110.02(6)(e)). Special rules apply to insurance-funded exterior repairs (Wis. Stat. § 100.65).
The law: Wis. Admin. Code ch. ATCP 110 (Home Improvement Practices), §§ 110.02, 110.025, 110.05, 110.07; Wis. Stat. §§ 423.201–423.205
Good to know: In Wisconsin, if you paid up front and the contractor misses the contract deadline without getting your OK to a new date, you can cancel in writing, and the contractor has 15 days to return any money not yet spent on your job.

Contractor deposit limits in every state

Mechanics lien deadlines in Wisconsin

Lien deadline (prime): File the lien claim with the circuit court clerk within 6 months after last furnishing, and serve a copy on the owner within 30 days after filing (Wis. Stat. § 779.06(1)).
Lien deadline (sub/supplier): Same as prime.
Preliminary notice (sub/supplier): Required. Written notice (two signed copies) to the owner within 60 days after first furnishing; without it there's no lien, and a late notice covers only work after the owner receives it (Wis. Stat. § 779.02(2)(b), (3)).
Notice of intent: Required for all claimants: written notice of intent to file a lien claim served on the owner at least 30 days before filing, even if a § 779.02 notice was given (Wis. Stat. § 779.06(2)).
Enforce within: Action within 2 years after filing the lien claim (Wis. Stat. § 779.06(1)).
Homeowner rules: The prime contractor's required notice warns owners that unpaid subs and suppliers can lien and recommends lien waivers; owners must pass sub notices to their mortgage lender within 10 days (Wis. Stat. § 779.02(2)).
The law: Wis. Stat. Ch. 779, Subch. I (Construction Liens), §§ 779.01-779.17
Good to know: Wisconsin requires three steps for most residential liens: the early notice (prime in the contract, subs within 60 days), a 30-day notice of intent, and filing within 6 months of your last work.

Mechanics lien deadlines in every state

Workers' comp requirements in Wisconsin

Who must carry it: Coverage is required once an employer has 3 or more full- or part-time employees (from the day the 3rd is hired), or has paid $500 or more in gross wages in any calendar quarter for work in Wisconsin (by the 10th day of the next quarter). Farmers: 6 or more employees on the same day for 20 days a year (Wis. Stat. § 102.04(1)(b); Wisconsin DWD).
Owners and officers: Sole proprietors, partners and LLC members are exempt but may elect coverage by endorsement. Corporate officers are employees; in a closely held corporation (10 or fewer stockholders), 1 or 2 officers may exclude themselves but still count toward the thresholds. A corporation with only 1 or 2 officers and no other employees may file a Notice of Corporate Officer Option instead of buying a policy (Wis. Stat. §§ 102.075, 102.076; DWD WKC-13324-P).
Subcontractors: Wisconsin's rule making an employer liable for an uninsured contractor's or sub's employees (Wis. Stat. § 102.06) is suspended while the Uninsured Employers Fund is accepting claims (DWD WKC-1-P). An injured independent contractor is treated as an employee unless all nine tests of § 102.07(8) are met, and no employer may claim coverage under another employer's or contractor's policy (Wisconsin DWD), so make sure every sub carries its own policy.
Homeowners: Household workers hired for general household services in a private home are excluded as domestic servants (Wis. Stat. § 102.07(4)(a)).
Penalties: Twice the unpaid premium for the uninsured period or $750, whichever is greater; a closure order requiring the employer to cease operations until insured; personal liability to reimburse the Uninsured Employers Fund for benefits paid; penalties are mandatory and non-negotiable (Wis. Stat. §§ 102.28(4), 102.82, 102.85; DWD WKC-13324-P).
The law: Wis. Stat. Ch. 102; §§ 102.04, 102.06, 102.07, 102.28, 102.85
State agency: Wisconsin Department of Workforce Development, Worker's Compensation Division
Good to know: Wisconsin requires coverage at 3 employees, or as soon as you pay $500 in wages in a quarter, so even one part-timer can trigger it. You can't rely on a contractor's policy to cover your own workers, and penalties are at least $750.

Workers' comp requirements in every state

Planting zones in Wisconsin

2023 USDA zones: 3b to 6a
Coldest-night range: −35°F to −5°F
Coldest area: Small areas of southern Douglas, northern Washburn and Sawyer counties near Hayward
Warmest area: The western shore of Lake Michigan (Kenosha County, southeastern Sheboygan County, Washington Island)
Example cities: Milwaukee: 6a, Madison: 5b, Green Bay: 5b, Eau Claire: 4b
Local plant advice: University of Wisconsin-Madison Division of Extension
Good to know: Wisconsin gained its first zone 6a area along the Lake Michigan shore, and zone 3 has almost vanished, now found only in small pockets near Hayward.

Planting zones in every state

Frost dates in Wisconsin

Station	Last spring frost	First fall frost	Frost-free days
Milwaukee Lake Michigan shore	April 19	October 29	192
Madison South-central Wisconsin	May 1	October 10	160
Green Bay Northeast Wisconsin	April 30	October 9	161
Rhinelander Northwoods	May 26	September 23	120

Typical range: Last frost mid-Apr (Milwaukee) to late May (Rhinelander); first frost late Sep (Rhinelander) to late Oct (Milwaukee)
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 Wisconsin, the last spring frost at the stations listed ranges from mid-April around Milwaukee to late May around Rhinelander.

Frost dates in every state

Frequently Asked Questions

What building code does Wisconsin use?

Wisconsin Uniform Dwelling Code (Wis. Admin. Code SPS 320-325), the state’s own code, not the IRC. 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 Wisconsin?

The state sets 48 in. below adjacent grade (Uniform Dwelling Code, SPS 321.16). Footings for houses, additions and attached decks go below it.

How much can a contractor ask for up front in Wisconsin?

No statewide cap. If any payment is due before the work is complete, the contract must be in writing (Wis. Admin. Code ATCP 110.05). Cancel rights: Home solicitation sales over $25 (face-to-face, phone or mail solicitation away from the seller’s usual place of business): 3 business days to cancel, excluding weekends and holidays (Wis. Stat. §§ 423.201, 423.202). Separately, if you paid in advance and the contractor misses a contract deadline (or doesn’t give notice of a delay and get your agreement to a new deadline), you may cancel by written notice and demand your unspent payments, which the contractor must refund within 15 days, plus a written accounting within 30 days (ATCP 110.07).

How long does a contractor have to file a mechanics lien in Wisconsin?

File the lien claim with the circuit court clerk within 6 months after last furnishing, and serve a copy on the owner within 30 days after filing (Wis. Stat. § 779.06(1)). Subcontractors and suppliers may have different notice rules; see the section above.

What planting zone is Wisconsin?

On the 2023 USDA map, Wisconsin runs from zone 3b to 6a. Examples: Milwaukee 6a, Madison 5b, Green Bay 5b. Enter your ZIP on the USDA map for your exact zone.

Do contractors need workers' comp in Wisconsin?

Coverage is required once an employer has 3 or more full- or part-time employees (from the day the 3rd is hired), or has paid $500 or more in gross wages in any calendar quarter for work in Wisconsin (by the 10th day of the next quarter). Farmers: 6 or more employees on the same day for 20 days a year (Wis. Stat. § 102.04(1)(b); Wisconsin DWD). Owner exemptions and subcontractor rules are in the workers’ comp section above.

When is the last frost in Wisconsin?

At the NOAA stations we list: Last frost mid-Apr (Milwaukee) to late May (Rhinelander); first frost late Sep (Rhinelander) to late Oct (Milwaukee). 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.

Wisconsin 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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