Jefferson County, MO Building Safety: Building Permits (2026)

420 of the Jefferson County code bars anyone from erecting, constructing, enlarging, altering, repairing, remodeling, moving, converting or demolishing any building, structure or activity regulated by the Building Code without first obtaining a separate permit for each building or structure. 99 acres or less that will sit within 100 feet of a property line must include a site plan showing property lines and building lines, with the structure's location staked by a licensed professional land surveyor and the plan signed and sealed by a surveyor or engineer; attached decks and structures under 200 square feet are excused from the staking and seal requirement.

440. Residential permit fees are set by a construction-cost table: a $1 to $2,000 project costs $200, a $5,001 to $10,000 project costs $480, and fees climb from there as the declared construction cost rises, with separate schedules for commercial, industrial and manufactured housing work. 065 must be completed, meaning the work has passed final inspection, within one year, or 180 days for a demolition permit, and the Code Official can grant only a limited extension for reasonable cause; if the deadline passes with work unfinished, the Code Official can order the property's utility service disconnected.