The City of Lake Saint Louis’s Building Division reviews plans, issues building permits and inspects construction inside city limits; St. Charles County handles the septic and blasting permits the City contracts to it. Apply online in Citizenserve. Most permits cost 0.6% of the estimated construction cost plus 0.12% for plan review, with minimums, and residential reviews take about 10–14 days.
What requires a building permit in Lake Saint Louis?
Permit needed
- New homes and commercial buildings
- Additions and alterations that create new habitable or occupiable space
- Basement finishes, interior remodels and repairs
- Decks, pergolas, fences and similar structures
- Swimming pools
- New or modified electrical, plumbing and mechanical systems
- Demolition and floodplain development
- Driveways and work in the right-of-way (Public Works permit)
No permit
- Roof replacement (drip edge is still required)
- Patios and other flatwork on your own lot that is not part of a driveway
Fences: fences are generally not allowed in Lake Saint Louis except around an in-ground swimming pool and in the areas shown on the City’s Residential Fence Map, and any fence needs a permit first. Solar panels follow the City’s solar guide and code section 420.150 M.
Lake Saint Louis building department: who handles permitting
The Department of Community Development has three divisions, Planning and Zoning, Building, and Code Enforcement. The Building Division issues permits and inspects construction; James Hoeltge is the Chief Building Official and Andrew Stanislav is the Director of Community Development.
| Need | Contact |
|---|---|
| Permit Technician (applications, rental inspections) | 636-625-7937 |
| Chief Building Official | James Hoeltge, 636-625-7984 |
| City Hall | 200 Civic Center Drive, Lake Saint Louis, MO 63367; 636-625-1200 |
| Driveways and right-of-way | Public Works, 636-695-4221 |
| Septic and blasting permits | St. Charles County (by contract with the City) |
Short on time to read all of this?
Get a free quote →Contractor business licence: every contractor working in the city needs a Lake Saint Louis contractor business licence, applied for in Citizenserve with a certificate of insurance showing workers’ compensation (or a notarized exemption affidavit). It costs $100 a year, $50 if you apply after January 1, and expires each June 30. Electrical, plumbing and mechanical work must be done by contractors licensed with St. Charles County, apart from the limited homeowner work described below.
Lake Saint Louis permits and the Citizenserve portal
Use the Citizenserve Online Portal to apply, upload plans, check status and request inspections; for example, a basement finish is filed as a Residential Alteration Permit Application. The Building Division publishes guides for asphalt shingle roofing, basement finishes, decks, demolition, drainage, cold-weather concrete, pools, solar panels and rental inspections.
Homeowner work: an owner who lives full time in a detached single-family home may do limited trade work after passing the Lake Saint Louis Homeowner Code Examination: replacing mechanical equipment with equipment of the same capacity, adding 120-volt branch circuits, and replacing or repairing existing piping, including finishing a roughed-in basement bathroom. New panels or service changes, EV charging stations, added mechanical equipment and sewer or water service work stay with County-licensed contractors, and all of it needs a permit.
Lake Saint Louis permit fees
Fees are set in Section 135.110 of the City Code, last amended by Ordinance 4854 on February 17, 2026. The cost of construction is estimated with the International Code Council permit formula, and you pay the permit fee plus the plan review fee.
Not sure this scope needs a permit?
Get a free quote →| Category | Permit fee | Plan review fee |
|---|---|---|
| New building | $125 or 0.006 × cost above $20,834 | $100 or 0.0012 × cost above $83,334 |
| Addition (room additions, sun rooms) | $125 or 0.006 × cost above $20,834 | $50 or 0.0012 × cost above $41,667 |
| Alteration or repair (remodels, basement finishes, foundation and fire repairs) | $100 or 0.006 × cost above $16,667 | $50 or 0.0012 × cost above $41,667 |
| New structure (fence, deck, pergola) and MEP permits | $50 or 0.006 × cost above $8,334 | $25 or 0.0012 × cost above $20,834 |
| Swimming pool | $125 or 0.006 × cost above $20,834 | $50 or 0.0012 × cost above $41,667 |
| Demolition | $150 | $25 or 0.0012 × cost above $20,834 |
| Extra inspection | $35 each | – |
For example, a new house with an estimated construction cost of $400,000 pays $2,400 for the permit and $480 for plan review, $2,880 in all. A $40,000 basement finish pays $240 for the permit and the $50 minimum for plan review.
The fee table posted on the Building Permits page is dated March 1, 2024; the Code section as amended by Ordinance 4854 in February 2026 keeps the same rates and adds a repair category. A floodplain development permit starts at $100. Rental inspection fees are listed under Local rules.
Electrical, plumbing and mechanical permits in Lake Saint Louis
The Building Division issues mechanical, electrical and plumbing (MEP) permits at $50 or 0.6% of cost, plus $25 or 0.12% for plan review. Installing or changing electrical and plumbing systems requires a permit and a contractor licensed in that trade, which in Lake Saint Louis means licensed with St. Charles County, unless an owner-occupant has passed the City’s homeowner examination for the limited work it allows. Trade work follows the 2020 National Electrical Code and the 2021 plumbing, mechanical and fuel gas codes.
Private sewage disposal (septic) permits are issued by St. Charles County under its contract with the City.
Rather talk it over?
Call 1-855-478-4290 →Alliance handles electrical permit filing for contractors here. More on this: who pulls the electrical permit.
Application documents
Plans are uploaded to Citizenserve with the application. For a basement finish the City asks for a complete set of scaled plans showing:
- Framing details, materials and spacing
- Plumbing fixture types and locations
- Electrical outlets, switches and lights
- Mechanical supply and return registers and exhaust fan details
- All room dimensions, ceiling heights and room labels
Decks, pools and solar installations each have their own City guide or checklist; the pool checklist lists what an in-ground pool permit needs.
How to apply for a Lake Saint Louis permit
Confirm setbacks and whether a fence is allowed on your lot before you design the project.
Every contractor needs a City contractor business licence, and trade contractors a St. Charles County licence.
Create an account and start the permit application that matches the work.
Attach the drawings with the application so plan review can start.
Allow about 10–14 days for residential and 14–21 days for commercial review, then pay the permit and plan review fees.
Ask for each inspection in Citizenserve or by email before 3:30 p.m. the business day before.
Lake Saint Louis inspections
Request inspections in Citizenserve or by email to the Building Division’s inspection address (buildinginspections@lakesaintlouis.com on the Building Division page, buildinginspections@lakesaintlouismo.gov on the Building Permits page) with the permit number, address, requested date and a morning or afternoon window. The City’s FAQ gives the windows as 9 a.m.–12 p.m. and 1–4 p.m., and requests must be in by 3:30 p.m. on the business day before. Extra inspections cost $35 each.
Rather not deal with the building department?
Get a free quote →A basement finish needs a plumbing ground rough inspection for new plumbing under the slab, a complete rough inspection after framing, fire blocking and trade rough-ins and before insulation or drywall, and a final inspection before the rooms are used.
Local Lake Saint Louis rules
Rental inspections: every rental unit must be registered with the Chief Building Official and inspected for a certificate of occupancy before each new tenant. Inspecting an unoccupied detached unit costs $75 and an unoccupied attached unit $50; an occupied unit costs twice as much. Apply in Citizenserve.
Home sales: the City does not inspect homes for sale, but the Lake Saint Louis Fire District may require a home sale inspection (636-561-9200).
Floodplain: Lake Saint Louis is in the National Flood Insurance Program on flood maps dated January 20, 2016. Development in the mapped A and AE zones needs a floodplain development permit, and new or substantially improved homes must have the lowest floor, including the basement, 3 feet above base flood elevation; non-residential buildings must reach the same height or be floodproofed. The Chief Building Official is the floodplain administrator.
Construction hours: 6:30 a.m.–8 p.m. on weekdays, 9 a.m.–6 p.m. on Saturdays and 12–6 p.m. on Sundays.
Missouri building code
Missouri has no mandatory statewide building code for private construction: a county, fire protection district or municipality may adopt one (usually by reference under RSMo 67.280), and in parts of the state none has. Building codes in Missouri
Lake Saint Louis building permit FAQ
Who issues building permits in Lake Saint Louis?
The City’s Building Division in the Community Development Department. St. Charles County handles septic and blasting permits, and some public health permits, under contracts with the City.
How much does a building permit cost in Lake Saint Louis?
Generally 0.6% of the estimated construction cost plus 0.12% for plan review, with minimums of $50–$125. A $400,000 house pays $2,880 in permit and plan review fees.
Want this handled start to finish?
Get a free quote →Do I need a permit to replace my roof?
No, but drip edge is required on roof replacements.
Can I build a fence in Lake Saint Louis?
Usually only around an in-ground pool or where the City’s fence map allows, and always with a permit.
How long does plan review take?
About 10–14 days for residential permits and 14–21 days for commercial permits.
Can I do my own electrical or plumbing work?
Only limited work, in a detached home you live in full time, after passing the City’s homeowner code examination and getting a permit.
Which building code does Lake Saint Louis use?
The 2021 International Codes, the 2020 National Electrical Code and the 2015 International Energy Conservation Code, for permits issued after March 1, 2024.
Lake Saint Louis permit search and official resources
These are the primary sources behind this guide. Codes, fee schedules and procedures change — confirm the position for your filing date.
- Lake Saint Louis Building Division
- Lake Saint Louis building permits and guides
- Lake Saint Louis Citizenserve portal
- Lake Saint Louis 2021 construction codes
- Lake Saint Louis Code Section 135.110, Building Division fees
- Lake Saint Louis fee table (March 2024)
- Lake Saint Louis Community Development FAQs
- Lake Saint Louis homeowner trade work policy
- Lake Saint Louis contractor business licence
- Lake Saint Louis home sale and rental inspections
- Lake Saint Louis Code Section 425.710, floodplain standards
Inspections are where schedules slip.
Get a free quote →Simplify Lake St. Louis permitting with Alliance Permitting
Alliance Permitting is a permit documentation and submission company in Missouri. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.
Ready to break ground in Lake St. Louis sooner?
Let Alliance prepare, file, and track your Lake St. Louis permits while your crew stays on the job.
More Missouri permitting guides
St. Charles County
Read guide →Dardenne Prairie
Read guide →O'Fallon
Read guide →Lawrence County Building Permit Guide
Read guide →Lebanon Building Permit Guide
Read guide →Lee's Summit Building Permit Guide
Read guide →This guide is provided by Alliance Permitting for general information about Lake St. Louis permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.