Zoning, building permits and septic rules in St. Louis, Missouri

St. Louis’s own rules

• Building permitRequired

  New residential construction and structural changes or major alterations inside St. Louis city limits.

  • Normal building maintenance generally does not require a permit.
  • Separate plumbing, mechanical, and electrical permits are required when applicable.
  • Historic-district and flood-zone rules can differ.

  “A building permit is required when any structural change or major alteration is made to an existing building or when any new construction is undertaken.”

• InspectionsRequired

  Residential properties subject to the City Housing Conservation District program inside St. Louis city limits.

  • The City states that 100% of property in St. Louis is located in a Housing Conservation District.
  • The inspection checks minimum interior building-code violations and minimum exterior standards.

  “100% of property in St. Louis is located in a Housing Conservation District. Ordinance No. 71835 requires a City Housing Conservation District Inspection of any property located in the district.”

• Certificate of occupancyRequired

  Residential sales, rentals, and vacant residential units before occupancy inside St. Louis city limits.

  • The City calls the document a Certificate of Inspection.
  • A certificate is valid for 12 months.
  • Rental dwelling units must be reinspected every three years or upon a change in occupancy; owner-occupied properties are exempt.

  “For residential sales, a Certificate of Inspection must be obtained before occupancy of the unit is permitted. For rental units, a Certificate of Inspection must be obtained before occupancy of the unit.”

• Local zoningPresent (with conditions)

  Land and development inside St. Louis city limits.

  • Building and occupancy permits are reviewed for Zoning Code compliance.

  “The Zoning Section of the Building Division reviews all building and occupancy permits for compliance with the Zoning Code Ordinance.”

• Building in a floodplainRequired

  All construction projects in City flood areas designated by FEMA Floodway or FIRM maps.

  • A Floodway Development Permit is required even if the Building Code does not require a building permit.

  “For all construction projects in an area designed as a flood area per the FEMA Floodway or FIRM maps, a Floodway Development Permit must be issued even though a building permit may not be required by the Building Code.”

• Permit feesPublished (with conditions)

  City building-permit applications inside St. Louis city limits.

  • Fees are non-refundable.
  • Only the application fee is due when filed; the permit fee is due after final approvals and when the permit is ready for issuance.

  application fee: 25 USD (per application) · permit fee over $3,000 estimated construction cost: per 10 USD per $1,000 estimated construction cost or fraction (plus $25 application fee)

  “Over $3,000.00 estimated construction cost or fraction thereof | $25.00 | $10.00 per thousand estimated construction cost or fraction thereof”

• Permit processPublished (with conditions)

  Building-permit applications inside St. Louis city limits.

  • Application may be made online or in person.
  • Project-specific City staff and agencies review an application.
  • The permit must be displayed onsite during construction after approval.

  “Once all assigned City agencies have approved your application, you will receive notification that your permit has been approved. At this time, you will be able to pay your permit fee and print the permit document, which needs to be displayed onsite during construction.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask St. Louis or St. Louis City directly.

• Owner-builder exemption — Owner-built residential construction inside St. Louis city limits.
• Building code adopted — Construction inside St. Louis city limits.
• Minimum dwelling size — Single-family A zoning district inside St. Louis city limits.
• Minimum lot size — Single-family A zoning district inside St. Louis city limits.
• Setbacks — Single-family A zoning district inside St. Louis city limits.

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Off-grid gear

Going off-grid in St. Louis means bringing your own water and power. The kit we’d start with:

• Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
• Power Bluetti Solar generators and home battery backup for living off the grid.
• Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
• Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.

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