St. Louis County, MO Solar Energy: Panel Permits (2026)
Key Facts
- Adopted solar code
- Uniform Solar Energy Code, 2015
- Adopting section
- SLCRO § 1103.P-020.1
- Mechanical cross-reference
- SLCRO § 1103.P-128(4)
- Electrical tie-in code
- NEC 2014, Chapter 1102
- Penalty for unpermitted work
- Up to $1,000 fine, 90 days jail
Summary
St. Louis County regulates solar energy system installations by adopting the 2015 Uniform Solar Energy Code into its Plumbing Code, and it separately requires solar equipment regulated by the Mechanical Code, such as fire suppression and fuel-fired tie-ins, to be installed to that code's standard. Photovoltaic wiring still needs its own electrical permit under the county's adopted National Electrical Code.
1103.P-020.1 - Plumbing and Drainage System Related Requirements from Supplemental Codes Adopted. —The "Uniform Swimming Pool, Spa, and Hot Tub Code", 2015 (hereinafter "USPSHTC") and the "Uniform Solar Energy Code", 2015 (hereinafter "USEC"), as published by the International Association of Plumbing and Mechanical Officials, are hereby referred to, adopted, and made a part hereof, as if fully set out in this chapter. ... 1103.P-128 - Permits from Other Authorities—Required. —...4.Mechanical Systems. When fire suppression systems, solar systems, medical gas systems, fuel gas systems, fossil fuel systems and other systems regulated by the Mechanical Code are installed; those systems shall be installed in accordance with the St. Louis County Mechanical Code.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 85 | Traffic: Supplement 80).
Full Breakdown
" That folds solar collector, piping, and mounting installation standards into the same Chapter 1103 permit and licensing framework already used for plumbing work: a permit must be obtained before covered installation work begins, and the work must be performed by an appropriately licensed tradesperson under this code. P-128(4) then draws the boundary with the county's separate Mechanical Code, stating that when solar systems (along with fire suppression, medical gas, fuel gas, and fossil fuel systems) are installed, those systems must be installed in accordance with the St.
Louis County Mechanical Code, Chapter 1108, rather than solely the Plumbing Code. Because solar photovoltaic wiring is electrical work, it also falls under the separately adopted 2014 National Electrical Code (Chapter 1102), which requires its own 24-hour-advance permit through the Office of Electrical Inspection. The prior version of this page cited only a mismatched chapter and ordinance number; the actual adopted USEC provision sits in the Plumbing Code chapter and carries far more specific installation and permitting content than a bare code-adoption blurb.
Violations & Fines
Because the Uniform Solar Energy Code is adopted as part of Chapter 1103, solar installation work performed without the required Plumbing Code permit or by an unlicensed installer is subject to the same misdemeanor penalty set out in Section 1103.P-140: a fine up to $1,000, imprisonment up to 90 days, or both, with each day of continued violation a separate offense, plus a separate no-permit penalty of up to the greater of $500 or 1% of construction cost.
Frequently Asked Questions
What code governs solar panel installation in St. Louis County?
Do I need more than one permit to install solar panels?
Does St. Louis County have a dedicated photovoltaic ordinance?
What happens if solar equipment is installed without following this code?
Sources & Official References
Other rules in St. Louis County
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