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Home  /  Solar site surveys  /  Wisconsin

Solar site surveys · Wisconsin

Solar site surveys in Wisconsin

A technician on the roof, in the attic and at the service panel, with the survey read against the code editions, AHJs and utilities that apply in Wisconsin.

Book a 15-min callWhat changes in Wisconsin
NEC 2023Electrical code in effect
3Utilities covered here
48 hrsSurvey to deliverable
Nationwide500+ technicians
Short answer

Wisconsin moved its statewide electrical code (SPS 316) from the 2017 NEC straight to the 2023 NEC on September 1, 2026. One- and two-family homes follow the state-written Uniform Dwelling Code rather than the IRC, so there is no IRC R324 pathway section for homes, and roof snow loads come from a two-zone map (30 psf in the south, 40 psf in the north). Export credit is set tariff by tariff: We Energies and WPS net monthly and pay an avoided-energy rate for any surplus.

What changes in Wisconsin

The capture spec is the same everywhere. What the engineer and the plan reviewer read it against is not.

WI · METROSMilwaukee
Code stack
2023NEC 2023National Electrical Code · effective Sep 1, 2026. Clearinghouse Rule CR 26-016 revised ch. SPS 316 to adopt the 2023 NEC with Wisconsin changes, effective September 1, 2026; the chapter previously adopted the 2017 NEC, so work permitted before that date may have been reviewed under the older edition.1,2
UDCDwelling code UDCThe Uniform Dwelling Code (SPS 320 to 325) is Wisconsin's own code for one- and two-family dwellings built since June 1, 1980, and it is not based on the IRC. Municipalities may not adopt their own rules on subjects the UDC covers, but they may apply it to additions and alterations and require permits for work outside its scope.3
2021IBC 2021The Wisconsin Commercial Building Code (SPS 361 to 366) adopts the 2021 IBC with state changes; the update (CR 23-007) took effect September 1, 2025. Only listed sections of the 2021 IFC apply through it, and Section 1205 on rooftop PV access is not among them.4
2012NFPA 1 2012Wisconsin's fire prevention code (SPS 314) adopts NFPA 1, Fire Code, 2012 edition, with state modifications, rather than the IFC.5
Rooftop fire access. The UDC chapters reviewed contain no solar-specific roof pathway section, and the commercial code does not pull in IFC Section 1205, so rooftop access spacing for PV is set case by case; ask the local building and fire officials what they expect before layout.6,4

Climate and site factors

Snow loads

The UDC designs roofs for the snow load on its zone map: 30 psf in Zone 2 across southern Wisconsin, including Milwaukee and Madison, and 40 psf in Zone 1 across the north, with reductions allowed on slopes steeper than 30 degrees.6

Wind

UDC dwellings must resist either a 20 psf horizontal and uplift pressure over the surface area or wind loads determined under ASCE 7-05.6

New NEC

Wisconsin skipped the 2020 NEC, so projects permitted on or after September 1, 2026 jump from 2017 to 2023 NEC requirements, including rapid shutdown and labeling changes.1

Solar access

Local rules and plat covenants that unduly restrict solar are limited or void by statute, and owners can seek compensation under s. 700.41 when a neighbor's structure outside the zoning envelope later shades their collector.7,8,9

Permitting in Wisconsin

Who reviews the plan set, and what the state layers on top.

Utilities and interconnection

There is no single statewide net metering tariff in practice: each utility files its own customer-generation rates with the PSC, while interconnection follows the common PSC 119 rule.11,10

We Energies

Serves more than 1.1 million electric customers in Wisconsin, including Milwaukee. Systems of 300 kW or less use its streamlined interconnection path, and net-metered customers are billed under rate schedule CGS NM.12,11

Interconnection page ↗

Wisconsin Public Service WPS

Serves about 474,000 electric customers in northeastern and north central Wisconsin. Its PG-4 net energy billing rate covers renewable systems of 20 kW or less sized to the customer's expected load.13,14

Interconnection page ↗

Alliant Energy (Wisconsin Power and Light) Alliant

Alliant serves about 1 million electric customers across Iowa and Wisconsin and asks Wisconsin customers to follow its interconnection steps, suggesting installers run its Distributed Generation Assist check before applying.15,16

Interconnection page ↗
Export compensation. At We Energies, rate CGS NM (under 300 kW) nets usage against exports each month; a net surplus is paid at an avoided energy cost rate, $0.03636/kWh for flat-rate residential service from January 1, 2026, and kWh do not carry forward. WPS's PG-4 (20 kW or less) also nets monthly and credited net excess at $0.03141/kWh in its 2025 rate brochure, updated each January.17,18,14

What we capture on every Wisconsin survey

One standard, one visit, the same record in Wisconsin as everywhere else. What it gets checked against is the code stack above.

Roof and structure

  • Measured roof planes: pitch, azimuth, dimensions
  • Every penetration and obstruction, located
  • Rafter or truss size, spacing and span
  • Decking type and condition
  • Layer count at a cut edge
  • Setbacks and fire pathway constraints
  • Horizon shading capture per array area

Electrical and interconnection

  • Main breaker and bus bar rating, photographed separately
  • Meter location and configuration
  • Slot count: used, open, tandem, double-tapped
  • Available interconnection points
  • Existing loads and sub-panels
  • Conduit route, measured along the actual path
  • Grounding electrode and bonding path

Commercial buildings

  • Membrane type, age and condition, with drainage pattern
  • Bar joist depth, spacing and span
  • Deck type and gauge
  • Switchgear and available bus capacity
  • Access and lift constraints for the install crew

Every visit

  • Roof and electrical in one visit, no second trip
  • 48-hour turnaround from survey to deliverable
  • Photo documentation throughout
  • Permit sets available, stamped, 6 days from survey

Wisconsin solar survey FAQ

Which NEC edition applies to solar in Wisconsin?

The 2023 NEC, adopted in SPS 316 effective September 1, 2026. Before that date Wisconsin enforced the 2017 NEC.1

Does Wisconsin use the IRC for homes?

No. One- and two-family homes follow the state-written Uniform Dwelling Code (SPS 320 to 325), and commercial buildings follow the 2021 IBC through SPS 361 to 366.3,4

What roof snow load is used in Wisconsin?

The UDC zone map sets 30 psf for the southern zone and 40 psf for the northern zone; an engineered design may use site-specific values.6

Is there retail net metering in Wisconsin?

It depends on the utility tariff. We Energies and WPS net monthly and pay an avoided-energy rate of a few cents per kWh for any monthly surplus rather than carrying kWh forward.18,14

Can a Wisconsin town or subdivision block solar panels?

Local governments may restrict solar only for health or safety or where the rule does not significantly add cost or reduce efficiency, and plat restrictions that unduly restrict solar are void.7,8

Services and further reading

Metro pages for Wisconsin: Milwaukee.

Residential

Roof, attic and service panel in one visit

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Commercial & Industrial

Roof, structure and switchgear

Explore →

Utility-Scale

Terrain, build and operations

Explore →

Site surveys

Roof and electrical, one visit

Explore →

Permitting & engineering

Stamped sets, six days from survey

Explore →

Shading analysis

SA, TOF and TSRF per plane

Explore →

From Field Notes

Sources

Every local fact on this page links to where it came from. Codes, programs and tariffs change: confirm the current requirement with the AHJ and the utility before you design.

  1. https://docs.legis.wisconsin.gov/ruletext/CR%2026-016
  2. https://content.govdelivery.com/accounts/WIDSPS/bulletins/1fd5c8c
  3. https://docs.legis.wisconsin.gov/code/admin_code/sps/safety_and_buildings_and_environment/320_325/320.pdf
  4. https://docs.legis.wisconsin.gov/code/admin_code/sps/safety_and_buildings_and_environment/361_366/361.pdf
  5. https://docs.legis.wisconsin.gov/code/admin_code/sps/safety_and_buildings_and_environment/301_319/314.pdf
  6. https://docs.legis.wisconsin.gov/code/admin_code/sps/safety_and_buildings_and_environment/320_325/321.pdf
  7. https://docs.legis.wisconsin.gov/document/statutes/66.0401
  8. https://docs.legis.wisconsin.gov/document/statutes/236.292
  9. https://docs.legis.wisconsin.gov/document/statutes/700.41
  10. https://docs.legis.wisconsin.gov/code/admin_code/psc/119.pdf
  11. https://www.we-energies.com/services/resources-cogs
  12. https://www.we-energies.com/services/wi-customer-owned-generation
  13. https://www.wisconsinpublicservice.com/company/about
  14. https://www.wisconsinpublicservice.com/payment-bill/inserts/2025-01-wi-parallel.pdf
  15. https://www.alliantenergy.com/who-we-are/about-alliant-energy
  16. https://www.alliantenergy.com/ways-to-save/customer-interconnection
  17. https://www.we-energies.com/pdfs/etariffs/wisconsin/cgs-nm.pdf
  18. https://www.we-energies.com/services/pdf/net-metering.pdf

Researched September 30, 2026.

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