Do I need a permit in Brentwood, Missouri?
Brentwood is a suburban community in the St. Louis area with relatively straightforward permit requirements, but the city enforces them consistently. The City of Brentwood Building Department administers the International Building Code (with Missouri amendments) and takes a measured approach to owner-builder work — you can pull permits for your own owner-occupied home without being a licensed contractor, which opens the door for many DIY and semi-DIY projects. That said, the city does require permits for the projects most homeowners tackle: decks, fences, room additions, finished basements with egress windows, electrical upgrades, plumbing work, and HVAC replacements. The 30-inch frost depth in Brentwood (shallower than many Midwest jurisdictions) affects deck and fence footing requirements — you'll need to go deeper than you might in places with colder winters, but not as deep as northern climates. The city's online permit portal makes it easy to research requirements and check application status, though you'll want to call ahead or visit in person to clarify whether a specific project needs a permit before you invest time in an application.
What's specific to Brentwood permits
Brentwood adopts the International Building Code with Missouri state amendments. The most practical difference for homeowners is that Missouri allows owner-builders to pull residential permits for their own homes without a contractor's license — a significant advantage if you're planning major work like an addition or deck. However, that freedom comes with inspection responsibility: the city will inspect your work more carefully precisely because a licensed contractor isn't signing off on it. Have your code book handy and expect inspectors to look closely at egress, footings, electrical runs, and structural framing.
The 30-inch frost depth in Brentwood means deck footings, fence posts, and porch foundations need to reach below grade frost line, but the requirement is more forgiving than in northern states. Most cities in Missouri require 30 to 36 inches; Brentwood's 30-inch depth is typical for the region. That said, the city sometimes encounters karst terrain (south of the main urban area) and alluvial soils (along creek corridors), which can create foundation challenges — if your property has history of settling or if you're near a creek, mention it to the building inspector during your initial consultation. They may require a geotechnical opinion or stricter footing design.
Brentwood's approach to minor projects is reasonable but literal. Fence permits are required for most residential fences over 4 feet in height in any location, and all pool barriers regardless of height. Decks are always permitted — there's no exemption for small decks. Electrical work (whether a new circuit, a hot-tub hookup, or a 240V outlet) always needs a permit and a separate electrical subpermit. Water-heater replacements are often exempt if you're installing the same capacity and fuel type in the same location, but confirm with the department before you swap it out. The city processes most routine permits over-the-counter if your application is complete; plan-check review typically runs 3 to 5 business days for straightforward projects.
The online permit portal is your first stop: you can search permit history for your address, check application status, and often download application forms. However, the portal doesn't always clarify whether a specific project needs a permit — and some applications can't be filed online and must be submitted in person at city hall. Before you spend an hour filling out an application, call the Building Department or use the portal's contact form to confirm requirements. Inspectors are generally responsive to pre-application questions, and a 5-minute phone call beats a rejected application.
Seasonal note: Brentwood doesn't close inspections in winter, but frost-heave and footing inspections are most practical May through September. If you're planning exterior work (deck, fence, addition footing), schedule inspections during frost-season lows (October–April are risky) or spring/fall when the ground is stable. Spring brings a surge in permit filings — if you're hoping for a quick turnaround, file before mid-April.
Most common Brentwood permit projects
Almost every homeowner in Brentwood will need a permit for at least one project. Here are the ones that fill the building department's docket.
Brentwood Building Department contact
City of Brentwood Building Department
Brentwood City Hall, Brentwood, Missouri (verify exact address with city website)
Call 'Brentwood MO Building Department' to confirm current number
Monday–Friday, 8 AM–5 PM (verify locally; holiday closures may apply)
Missouri context for Brentwood permits
Missouri adopts the International Building Code and International Residential Code with state-level amendments; Brentwood enforces these codes. Owner-builders are allowed to pull residential permits for owner-occupied homes in Missouri — one of the more permissive states — but the responsibility for code compliance falls entirely on you, not a general contractor. This matters: if your deck fails inspection for improper footings or structural framing, the city will issue a stop-work order and you'll have to fix it before work resumes. Licensed electricians must pull electrical subpermits in Missouri (even if an owner-builder is doing the structural work), and plumbing and HVAC also require licensed subcontractors for most residential work, though Missouri allows owner-builders to do limited plumbing repairs in their own homes. If you're planning any significant project — addition, major renovation, electrical upgrades — confirm with Brentwood which trades require a licensed subcontractor and which you can tackle yourself. The state code edition adopted (typically updated every 3 years) will be listed on Brentwood's website; as of this writing, most Missouri jurisdictions use a 2018 or 2021 IRC base with state amendments.
Common questions
Do I need a permit for a deck in Brentwood?
Yes. All decks require a permit in Brentwood, regardless of height or size. The application is usually straightforward (site plan, footings detail, stairs detail, ledger connection if attached), plan review is fast for simple decks, and the permit fee is typically based on the deck's square footage. Expect the footing inspection to be thorough — the inspector will confirm that posts are properly sunk below the 30-inch frost line and set on undisturbed soil or gravel base. If your deck is attached to the house (common), the ledger connection gets extra scrutiny; IRC R403.1 requires the ledger to be bolted directly to the rim board, not to rim blocking alone.
What's required for a fence permit in Brentwood?
Brentwood requires a permit for any fence over 4 feet in height (measured from the higher of adjacent ground levels), and for any pool barrier fence or screening regardless of height. The application needs a site plan showing the fence line relative to property lines and any setback requirements. Pool barriers must meet additional safety standards (self-closing, self-latching gates; minimum heights and spacing rules). Typical fence-permit fees are $50–$150. As a practical note: the #1 reason fence permits get rejected is a site plan that doesn't clearly show where the fence will sit relative to property lines — if you're unsure of your exact lot lines, have them marked before you file. The city doesn't want you building 6 inches over the line into a neighbor's yard.
Can I do electrical work myself in Brentwood if I own my home?
You can pull a residential permit for owner-occupied electrical work in Brentwood under Missouri's owner-builder rules, but you'll need a licensed electrician to inspect the work before the city signs off. For simple projects (a new 15-amp circuit, an outlet swap, ceiling-fan wiring), many homeowners hire a licensed electrician to do the rough-in and final hookup while they do the prep work themselves — this keeps costs down. For more complex work (sub-panel upgrades, 240V circuits for major appliances, solar-system wiring), most homeowners hire the electrician to do the full job and pull the permit. In either case, an electrical subpermit is required; the electrician typically files it alongside the main building permit. The inspection covers all the usual suspects: wire gauge, breaker sizing, grounding, conduit runs, and proper labeling (NEC Article 200–220 compliance).
Do I need a permit to replace my water heater?
In most cases, no — but confirm with Brentwood first. A like-for-like replacement (same fuel type, same capacity, same location) usually doesn't require a permit in Missouri jurisdictions, including Brentwood. However, if you're upgrading to a larger capacity, changing fuel type (gas to electric, for example), or relocating the unit, a plumbing permit is required. The application is simple and the fee is modest, but the inspection will verify that the new unit is properly vented (if gas), bonded (if necessary), and connected to proper relief and shut-off piping. If your old water heater is in an attic or second-floor closet — a common arrangement in older St. Louis-area homes — the inspector will also verify pan and drain requirements (IRC P2801.6 and state amendments).
What's the cost of a typical residential permit in Brentwood?
Brentwood's permit fees are modest for a suburban St. Louis jurisdiction. A deck permit runs $75–$200 depending on size (typically 1–1.5% of estimated valuation). A fence permit is often a flat $50–$100. An electrical subpermit for a single-circuit addition is $25–$50. A full addition or major renovation will cost more — usually 1.5–2% of the estimated construction cost — but plan-check fees are bundled in, so there are no surprise add-ons. Call the Building Department or check the fee schedule on the city website to get exact numbers; fees are updated annually. Keep your permit receipt and final inspection sign-off — you'll need them for resale disclosure, insurance claims, or if you ever want to modify the work later.
How long does the permit process take in Brentwood?
For a straightforward permit (deck, fence, simple addition), plan check typically runs 3–5 business days. If the application is incomplete or the design raises code questions, review can stretch to 2–3 weeks. Inspections are usually scheduled within 3–5 days of a request once work is ready. Over-the-counter permits (simple projects with no plan-check delays) can sometimes be issued the same day. The key is completeness: a clear site plan, dimensions, materials specs, and footings/structural details will sail through. A vague application or missing information will get bounced back for revision.
What if I build without a permit in Brentwood?
The city takes code enforcement seriously. If an unpermitted project is discovered — whether through a complaint, a property inspection, or during a later permit application — the building department will issue a stop-work order and require you to either retroactively obtain a permit or remove the work. Retrofitting a permit application is possible but expensive: you'll pay the original permit fee plus a penalty (usually 100–300% of the base fee), and the inspector will scrutinize the work more closely than if you'd permitted it upfront. There's also liability exposure: if someone is injured on an unpermitted deck or by unpermitted electrical work, your homeowner's insurance may refuse to cover the claim. When you sell the home, the unpermitted work must be disclosed, which often kills the deal or triggers a renegotiation. The 90-second phone call to confirm whether you need a permit is free; the penalty for guessing wrong is expensive.
Does Brentwood allow owner-builders?
Yes. Missouri law allows owner-builders to pull residential permits for owner-occupied homes, and Brentwood honors that. You do not need a general contractor's license to pull a permit for your own home. However, trades like electrical and plumbing often require licensed subcontractors even if an owner-builder is managing the overall project — check with the Building Department for your specific scope of work. The advantage of owner-building is cost and control; the disadvantage is that you're liable for every code violation and you absorb 100% of the inspection burden. If work fails inspection, you fix it yourself (no contractor to dispute the finding). Most owner-builders succeed on straightforward projects (decks, fencing, room prep) and hire licensed trades for complex systems (electrical, plumbing, HVAC). It's a practical hybrid approach.
Ready to find out if your project needs a permit?
Start with a quick call to the Brentwood Building Department — they're responsive to pre-application questions and can confirm your project's permit status in a few minutes. If you have site plans or sketches, have them ready. If you're not sure whether your work is within scope, that's fine — describe what you want to build and let them guide you. The permit process is designed to be straightforward for routine projects. The work happens fastest when you file with a complete, clear application.