Black Jack, Missouri requires a building permit for new construction, structural changes and major alterations inside city limits1. The city reviews building plans for zoning compliance, and St. Louis County performs the building-permit inspections2. We could not confirm who issues septic permits inside Black Jack, so ask city hall and the St. Louis County Department of Public Health before planning a private system.
At a glance
- Building permit
- Required for new construction, structural changes and major alterations1
- Zoning
- City zoning review; $100 non-refundable zoning application fee3
- Inspections
- Performed by St. Louis County2
- Occupancy permit
- Required before moving into a dwelling4
- Plan review time
- 10 to 14 working days for building permits5
- Septic
- Private systems only where public sewer is unavailable; permit authority unconfirmed6
Who to call
Zoning
Zoning application and plan review for zoning compliance, occupancy permits, and questions about city permits
Contact details are copied from each office’s official page and were checked against it on October 24, 2026.
Off-grid gear
Going off-grid in Black Jack 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.
These are affiliate links — we may earn a commission, at no cost to you. As an Amazon Associate, Bolthole Index earns from qualifying purchases.
Do you need a building permit in Black Jack, Missouri?
Yes. Inside Black Jack city limits, a building permit is required when any structural change, major alteration or renovation is made to a structure, or when new construction is done1. Normal maintenance generally does not need one, and separate plumbing, electrical and mechanical permits apply when that work is involved1. Plan review for a building permit takes 10 to 14 working days, so build that into your schedule5.
Driveways are covered too: the city's code-enforcement page says permits are required for driveways7. Black Jack has adopted its own building code, and plan review checks the proposed work against it8.
Who issues building permits and inspects in Black Jack?
Black Jack contracts with St. Louis County Public Works to handle building permits and commercial inspections, while the city engineer and director of public works initially reviews building plans for zoning compliance9. All building-permit inspections are performed by St. Louis County29.
For questions about city permits, call Black Jack City Hall at 314-355-04009. The county's own building rules in Chapter 1115 govern unincorporated St. Louis County, not land inside Black Jack, so use them only as background10.
Does Black Jack have zoning, and what does it mean for RVs, tiny homes and lot size?
Black Jack runs its own zoning review inside city limits, and a $100 non-refundable zoning-application fee is due when you submit3. St. Louis County's zoning applies to unincorporated land; where a property is inside a municipality, the municipality's zoning approval is required instead11.
We could not confirm Black Jack's rules on RV occupancy, tiny homes, accessory dwellings, minimum lot size, setbacks or height limits. Ask City Hall at 314-355-0400 for the zoning district of the specific parcel before you buy9. Subdivision indentures can also add private restrictions beyond city zoning12.
How do septic permits work in Black Jack?
Black Jack's plumbing code allows a private sewage disposal system only where a public sewer is not available, and the system must be an approved one that works without surface discharge6. We could not confirm which office issues septic permits inside Black Jack city limits.
Across St. Louis County, a construction permit is required before installing or repairing most onsite wastewater systems, though some single-family lots may be exempt13. The state lists the St. Louis County Plumbing Department and the St. Louis County Department of Public Health as ordinance authorities, and incorporated areas may be handled differently14. Ask both City Hall and the county health department who handles your address before work starts.
Do you need an occupancy permit in Black Jack?
Yes. Occupancy of a dwelling in Black Jack is illegal without an occupancy permit, and you apply in person at City Hall4. A city inspection must find the dwelling free of health, safety and welfare issues first4. Published fees include a $125 first inspection and a $40 owner-occupied purchase occupancy permit; a home rental permit is $6515.
Building a home in Black Jack: the steps, in order
- Call Black Jack City Hall at 314-355-0400 to confirm the parcel's zoning district and what is allowed9.
- Submit the $100 zoning application so the city can review your plans for zoning compliance3.
- Apply for the building permit with a scaled site plan and one copy of detailed plans, then allow 10 to 14 working days for review5.
- Add separate plumbing, electrical and mechanical permits where they apply1.
- Have St. Louis County perform the building-permit inspections2.
- Get the occupancy permit at City Hall before moving in4.
What stays with St. Louis County, and what to check before you buy?
Building-permit inspections for Black Jack projects are performed by St. Louis County2. For land outside city limits, see the St. Louis County page. Flood rules are set by the county for unincorporated land, so ask whether a Black Jack parcel sits in a flood hazard area; we could not confirm a city floodplain rule.
Missouri requires a non-restricted permit to construct or repair a water well, though landowners may install their own well without a permit under the cited law and rules16. St. Louis County's effective property tax rate is 1.2%17.
Watch-outs
- Unconfirmed in Black Jack: RV and tiny-home occupancy, minimum lot size, setbacks and septic permit authority, so call City Hall at 314-355-04009.
- A mismatch of offices is easy to make: the St. Louis County building code covers unincorporated land, while Black Jack's own permit and zoning process applies inside city limits101.
- Occupancy fees are not refundable, and a conditional certificate of occupancy is not allowed except for exterior seasonal repairs415.
Sources
- Building Permits | Black Jack, MO (Black Jack), quoted and re-checked
- Forms, Permits & Applications | Black Jack, MO (Black Jack), quoted and re-checked
- Forms, Permits & Applications | Black Jack, MO (Black Jack), quoted and re-checked
- Occupancy Permits & Inspections | Black Jack, MO (Black Jack), quoted and re-checked
- Building Permits | Black Jack, MO (Black Jack), quoted and re-checked
- Article VII - Plumbing | Code of Ordinances | Black Jack, MO (Black Jack), quoted and re-checked
- Code Enforcement | Black Jack, MO (Black Jack), quoted and re-checked
- Building Permits | Black Jack, MO (Black Jack), quoted and re-checked
- City of Black Jack, City Hall (cityofblackjack.com)
- Chapter 1115 - Building Code, quoted and re-checked
- Residential Above Ground Swimming Pool Checklist and Guide for a Building Permit, quoted and re-checked
- Single-Family Dwelling Design Checklist, quoted and re-checked
- OWTS Construction Permit Process, quoted and re-checked
- OWTS Construction Permit Process — St. Louis County authorities, quoted and re-checked
- Occupancy Permits & Inspections | Black Jack, MO (Black Jack), quoted and re-checked
- Water Wells - PUB2945, quoted and re-checked
- Effective property tax rate: Bolthole Index county data
Written October 24, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.