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St. Charles County, MO Building Safety: Plumbing Permits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Adopted code
2021 County Plumbing Code
Residential permit fee
$60
Commercial permit fee
$80
Permit expiration
180 days if unstarted
Max violation fine
$500 per day

Summary

St. Charles County requires a permit before any plumbing installation, alteration, or repair, charging $60 for residential work and $80 for commercial work under the adopted 2021 Plumbing Code.

These county ordinances apply to unincorporated areas of St. Charles County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

The Division of Building and Code Enforcement shall charge the following fees for permits issued under the Plumbing Code, Section 500.280 of this Title: (1) Sixty dollars ($60.00) or the estimated cost of construction multiplied by the "Permit Fee Multiplier"... whichever is greater, for residential construction. (2) Eighty dollars ($80.00)... for commercial construction.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4863880; v61 updated 2026-05-11; through 05-11-2026).

Full Breakdown

The county adopted the 2021 St. Charles County Plumbing Code by Ordinance No. 17-061 (as amended), enforced by the Division of Building and Code Enforcement within the Department of Community Development. A permit is required before plumbing work begins; the Division charges $60 for residential permits and $80 for commercial permits, or the estimated construction cost times the county's Permit Fee Multiplier, whichever is greater. Permits expire if work isn't started within 180 days.

Violations & Fines

Working without a permit or violating approved plans is a misdemeanor punishable by a fine up to $500, plus an added fee for work started before permit issuance; each day counts as a separate offense.

Frequently Asked Questions

Do I need a permit for plumbing work in St. Charles County?
Yes. Any plumbing installation, alteration, or repair requires a permit from the Division of Building and Code Enforcement, under the county's adopted 2021 Plumbing Code, Section 500.280.
How much does a plumbing permit cost?
$60 for residential work or $80 for commercial work, or the estimated construction cost times the county's Permit Fee Multiplier, whichever is greater, per Section 505.020.
What happens if I start plumbing work without a permit?
You owe an added fee on top of the permit fee, and code violations can bring a misdemeanor charge with a fine of up to $500 per day.

Sources & Official References

Other rules in St. Charles County

Fence Regulations: Height LimitsSome RestrictionsBuilding PermitsSome RestrictionsChildcare Center RulesSome RestrictionsFire Sprinkler RequirementsLight RestrictionsElectrical PermitsSome RestrictionsCarbon Monoxide DetectorsSome RestrictionsFence Regulations: Retaining WallsSome RestrictionsFence Regulations: Material RestrictionsSome RestrictionsAnimal Ordinances: Veterinary Clinic ZoningSome RestrictionsAnimal Ordinances: Pet Store RulesSome RestrictionsAnimal Ordinances: Mandatory Spay/NeuterSome Restrictions

All St. Charles County rules

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