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Home  /  Solar site surveys  /  Missouri  /  St. Louis

Solar site surveys · St. Louis, MO

Solar site surveys in St. Louis

Roof, attic and service panel captured in one visit, with the plan set built for the St. Louis AHJ you submit into and the utility that serves the address.

Book a 15-min callPermitting in St. Louis
NEC 2017Electrical code in effect
3AHJs covered here
48 hrsSurvey to deliverable
Nationwide500+ technicians
Short answer

In the City of St. Louis, the Building Division issues the building permit for solar and a licensed electrical contractor pulls the electrical permit, under the 2018 I-Codes and the 2017 NEC. Properties in local historic districts also go through Cultural Resources Office review, which may require panels to be hidden from public view. St. Louis County covers unincorporated areas under its own, older code set, and Ameren Missouri handles interconnection.

What changes in St. Louis

Missouri state rules apply here, plus whatever the local AHJ amends.

MO · ST. LOUISSt. Louis
Code stack
2017NEC 2017National Electrical Code · effective Aug 1, 2018. Missouri does not adopt the NEC statewide; each city or county picks its edition. The City of St. Louis adopted the 2017 NEC by Ordinance 70802 in August 2018, and St. Louis County's published code lists reference the 2014 NEC, so confirm the edition with each AHJ.1,2,3
2018IRC 2018Residential codes are adopted locally. The City of St. Louis uses the 2018 IRC (Ordinance 70795, August 1, 2018), while St. Louis County's residential solar checklist is based on the 2015 IRC with county amendments.1,3
2018IFC 2018Fire codes are also local. The City of St. Louis adopted the 2018 IFC (Ordinance 70796); in St. Louis County, fire protection districts adopt and enforce their own fire codes and may check array clearances and pathways.1,3
Rooftop fire access. Roof-access rules depend on the local code. Where the 2018 IRC is in force, as in the City of St. Louis, Section R324.6 calls for two 36-inch eave-to-ridge pathways and 18-inch ridge setbacks (36 inches above 33% coverage); in St. Louis County, the local fire protection district may review clearances and pathways around panels.1,4,3

Climate and site factors

Historic districts

Some St. Louis historic districts require panels to be invisible from public areas, while others allow limited visibility; a non-historic addition on the same lot is the preferred location when one exists.5

Solar-ready rule

Since January 23, 2020, the city's solar-ready ordinance requires new homes and commercial buildings to show on plans how a future solar system could be installed.6,7

Wind and seismic

St. Louis County's bracing guide sets a 90 mph wind speed and Seismic Design Category C for one- and two-family homes.8

Fire districts

In St. Louis County, the local fire protection district may check clearances and pathways around panels in addition to the county's permit review.3

Permitting in St. Louis

The main AHJs, and how the rest of the metro splits up.

City of St. Louis Building Division

Solar installation needs a building permit, and a licensed electrical contractor must obtain a separate electrical permit for the connection to the existing electrical system; the city enforces the 2018 IBC, IRC and IFC and the 2017 NEC.9,1,10

Official page ↗

City of St. Louis Cultural Resources Office and Preservation Board

In local historic districts, solar is reviewed against each district's standards and the Preservation Board's policy, which uses either a no-visibility or a visual-compatibility test; submittals include a site plan, a roof installation plan with a section, and photos from the sidewalk and street.5,11

Official page ↗

St. Louis County Transportation and Public Works

The county's residential solar checklist is based on the 2015 IRC as amended by county ordinance, requires structural and electrical permits before work starts, and asks for electronically submitted plans with each array dimensioned on the roof plan.3

Official page ↗

Across the metro

Many St. Louis County municipalities adopt their own code editions, while the county handles unincorporated areas; St. Charles County cities such as Lake Saint Louis have moved to 2021 codes, and Illinois suburbs across the river follow Illinois rules and Ameren Illinois.3,12

Missouri-wide rules that still apply

Utilities and interconnection

Ameren Missouri serves the City of St. Louis, and the city points residents to Ameren for utility incentives and community solar.7,16

Ameren Missouri

The investor-owned utility serving the City of St. Louis, based in St. Louis. Customers or installers apply online for interconnection and net metering, net-metering agreements are capped at 100 kW, and net excess energy is credited at an avoided fuel cost of 3.84 cents per kWh in summer and 3.39 cents in winter under the tariff effective March 1, 2025.16,17,7

Interconnection page ↗
Export compensation. As of September 2026, the Net Metering and Easy Connection Act (386.890 RSMo) nets usage and generation each billing period for systems up to 100 kW, and any net excess is credited at no less than the utility's avoided fuel cost; the statute lets unused credits lapse after twelve months, though Ameren Missouri says its credits carry over until used.15,17,16

What we capture on every St. Louis survey

The same capture standard as every other Missouri job, so the plan set is built on what the technician verified on site.

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

St. Louis solar survey FAQ

What permits does solar need in the City of St. Louis?

A building permit for the installation plus an electrical permit obtained by a licensed electrical contractor.9,10

Which codes apply to solar in the City of St. Louis?

The 2018 IBC, IRC and IFC and the 2017 NEC, all adopted effective August 1, 2018.1

Can I install solar in a St. Louis historic district?

Yes, with Cultural Resources Office review; depending on the district, panels must either be invisible from public areas or visually compatible with the building.5,11

What does Ameren Missouri pay for excess solar energy?

Net excess energy is credited at avoided fuel cost, 3.84 cents per kWh in summer and 3.39 cents in winter under the tariff effective March 1, 2025.17

Who reviews solar in unincorporated St. Louis County?

St. Louis County Transportation and Public Works, using a checklist based on the 2015 IRC with county amendments; the local fire protection district may also review pathways.3

Services and further reading

State-level detail is on the Missouri page; every location is on the solar site survey hub.

Residential

Roof, attic and service panel in one visit

Explore →

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://www.stlouis-mo.gov/government/departments/public-safety/building/building-codes.cfm
  2. https://stlouiscountymo.gov/st-louis-county-departments/transportation-and-public-works/publications-and-manuals/notices-to-the-public/mep-notices/master-plan-code-updates
  3. https://stlouiscountymo.gov/st-louis-county-departments/transportation-and-public-works/publications-and-manuals/pw-residential-guides/solar-panels1/
  4. https://up.codes/s/roof-access-and-pathways
  5. https://www.stlouis-mo.gov/government/departments/planning/cultural-resources/documents/upload/Solar-Panel-Installation-Policy-for-Local-Historic-Distric.pdf
  6. https://www.stlouis-mo.gov/government/departments/public-safety/building/permits/index.cfm
  7. https://www.stlouis-mo.gov/government/departments/planning/sustainability/solar-and-the-city.cfm
  8. https://stlouiscountymo.gov/st-louis-county-departments/transportation-and-public-works/publications-and-manuals/pw-residential-guides/wind-and-seismic-bracing-guide
  9. https://www.stlouis-mo.gov/government/departments/public-safety/building/permits/building-permits/commercial-building-permits.cfm
  10. https://www.stlouis-mo.gov/government/departments/public-safety/building/permits/electrical-permit.cfm
  11. https://www.stlouis-mo.gov/government/departments/planning/cultural-resources/documents/guide-for-the-applicant.cfm
  12. https://www.lakesaintlouis.com/157/2021-Construction-Codes
  13. https://revisor.mo.gov/main/OneSection.aspx?section=442.404
  14. https://revisor.mo.gov/main/OneSection.aspx?section=442.012
  15. https://revisor.mo.gov/main/OneSection.aspx?section=386.890
  16. https://www.ameren.com/service/renewables/solar
  17. https://www.ameren.com/-/media/rates/files/missouri/uecsheet171eppnetmetering.pdf

Researched September 30, 2026.

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