Bathroom Remodel Permit in University City, MO (2026)

Research by DoINeedAPermit Research Team · Updated May 2026

The Short Answer

If you're relocating plumbing fixtures, adding electrical circuits, installing a new exhaust fan, converting tub to shower, or moving walls, you need a permit from the City of University City Building Department. Surface-only work (tile, vanity swap in place, faucet replacement) is exempt.

University City, a residential enclave within the St. Louis metro area, enforces the Missouri State Building Code (currently the 2015 International Building Code with local amendments) through the City of University City Building Department. What sets University City apart from surrounding unincorporated St. Louis County is its tighter permitting standards for bathroom water-intrusion details: the city explicitly requires a detailed waterproofing assembly specification (cement board plus membrane, or equivalent liquid-applied system) for any shower or tub conversion, whereas some neighboring jurisdictions allow field-standard methods without showing the specification upfront. University City also operates a permit portal that processes most bathroom remodels over the counter for plan review, meaning you can often get approval in 1-2 weeks if your plans are complete on first submission — faster than the county's typical 3-4 week cycle. The city's frost depth of 30 inches and loess-based soil mean any new drain work must account for proper slope and future settling; the karst geology to the south also means some properties may have special foundation or drainage conditions flagged during review. Owner-builders are allowed for owner-occupied homes, but you must pull permits in your own name and pass all inspections; hiring a licensed contractor is typical for plumbing and electrical portions of a full bath remodel.

What happens if you skip the permit (and you needed one)

Stop-work orders in University City carry a $250–$500 administrative penalty, plus you'll owe double the original permit fee when you finally pull it — a full bathroom remodel permit is typically $400–$800, so you're looking at $800–$1,600 in total fees.
Insurance denial: many homeowner policies exclude coverage for unpermitted plumbing or electrical work, leaving you liable for water damage or electrical fires; claim denial language often cites 'unpermitted alterations' as grounds for rescission.
Resale disclosure: Missouri requires sellers to disclose unpermitted work on the seller's affidavit; buyers can walk away or demand the work be brought into compliance at your cost, typically $2,000–$5,000 in expedited permitting and inspection fees.
Refinance blocking: lenders and appraisers will flag unpermitted bathroom plumbing or electrical upgrades during a refi; you cannot close until permits are retroactively obtained or the work is removed, delaying closing by 4-8 weeks and costing $1,500–$3,000 in compliance work.

University City bathroom remodel permits — the key details

The City of University City Building Department enforces the 2015 International Building Code as adopted by the State of Missouri, with local amendments that tighten moisture and ventilation standards. The most critical rule for any bathroom remodel that involves a tub-to-shower conversion or new shower enclosure is IRC R702.4.2 and the city's local interpretation: you must provide a waterproofing assembly detail that specifies cement board (minimum 1/2 inch) plus a liquid-applied or sheet membrane (such as RedGard, Kerdi, or equivalent), or an alternative approved system like prefabricated waterproofed panels. This detail must be shown on your permit plan, not assumed or installed ad-hoc. The city's plan reviewer will not approve a remodel without this specification, and the inspector will verify the membrane is properly installed before drywall or tile goes up. Why this matters: water intrusion into the framing is the leading cause of mold and structural rot in bathrooms, especially in Missouri's humid climate. The cost of a waterproofing assembly is $200–$400 in materials and labor, far less than mold remediation later.

Electrical work in a full bathroom remodel triggers two code requirements that University City strictly enforces: GFCI (ground-fault circuit interrupter) protection and AFCI (arc-fault circuit interrupter) protection. Per NEC 210.8(A)(1), all receptacles within 6 feet of a sink must be GFCI-protected; per NEC 210.12(B), all branch circuits supplying outlets in the bathroom must have AFCI protection. University City requires these protections to be shown on an electrical single-line diagram or plan; you cannot simply install a GFCI outlet and leave the rest unprotected. If you're adding a new exhaust fan (which you should for humidity control), the duct must be rigid or semi-rigid (not flex) where it passes through the attic, must be insulated to prevent condensation, and must terminate at least 12 inches above the roof surface or as required by the soffit detail — no venting into the attic, period. The exhaust fan must be sized per IRC M1505.2, typically 50 CFM for a half bath, 50-75 CFM for a full bath, and 100+ CFM for a bathroom over 100 square feet. University City's plan reviewers will ask for the fan nameplate CFM and duct size (typically 4-6 inch) on your plans.

If you are relocating any plumbing fixtures — the toilet, vanity drain, or tub/shower drain — the trap arm (the horizontal drain line between the fixture trap and the vent stack) must comply with IRC P2706. The maximum trap arm length varies by pipe size but is typically 30 inches for a 1.5-inch line (common for sinks), 40 inches for a 2-inch line (common for showers/tubs), and 60 inches for a 3-inch or larger line (common for main stacks). University City's inspector will measure and verify trap arm slope (typically 1/4 inch per foot) and length on rough-in inspection. If your new drain run is longer than code allows, you'll need to vent it differently, which often requires going into the attic or walls — a costly change discovered during inspection. Plan ahead by measuring the distance from the proposed fixture to the existing vent stack before you design the layout. For a relocated toilet, the waste line must be 3 inches minimum and the vent cannot exceed 6 inches in horizontal distance from the toilet outlet; any longer and you need a separate vent or a relief vent.

If you are moving walls in your bathroom (common in full remodels where walls are reconfigured for layout or accessibility), you must check for structural consequences and utility conflicts. University City requires a framing plan showing wall locations, header sizes, and any bearing wall demolition; a half-bath partition wall is usually non-bearing and simple, but a wall adjacent to a load-bearing exterior wall or one that blocks a vent stack requires structural review. You also need to verify that any existing plumbing, electrical, HVAC, or gas lines in the wall being moved are shown on your plans and either relocated or capped appropriately. The building department will not issue a permit for wall demolition without a clear plan for utility displacement. The cost of a framing plan and structural review is typically $100–$300 if simple, $500–$1,500 if a beam is required. Additionally, if your home was built before 1978, lead-paint disclosure is mandatory: the building department will ask if you disturb any painted surfaces, and you must provide the federal lead disclosure document and be aware of renovation, repair, and painting (RRP) rules if lead is present.

University City's permitting process for bathroom remodels is streamlined compared to the county. You can typically submit plans via the city's online portal or in person at City Hall, and most applications are reviewed within 5-7 business days for standard remodels (no structural changes, straightforward plumbing/electrical). Plan reviewer feedback is usually emailed or provided at pickup, and revisions can be resubmitted without re-pulling the permit if done within 30 days. The permit fee is typically $400–$800 depending on the estimated cost of work (usually calculated at 1.5-2% of valuation, with a minimum of $150–$300). Once issued, you have 180 days to begin work and 12 months to complete it, with extensions available for cause. Inspections are scheduled online or by phone: rough plumbing (after drain and vent are roughed but before they're covered), rough electrical (after wiring is run but before it's covered), framing (if walls are moved), drywall/tile substrate (optional but recommended if waterproofing is new), and final inspection (all fixtures installed, tile complete, exhaust fan operational, electrical cover plates on, and rough-in inspections signed off). Plan for 2-3 weeks from permit issuance to final approval if inspections are scheduled efficiently.

Three University City bathroom remodel (full) scenarios

Scenario A

In-place cosmetic remodel — same vanity and toilet location, new tile and fixtures (Delmar Loop area bungalow)

You're gutting the tile walls and flooring, replacing the vanity cabinet in the exact same footprint, swapping the faucet and drain, and replacing the toilet with a modern low-flow model in the same location. You are not moving the drain lines, not adding new electrical circuits, not installing a new exhaust fan, and not touching the walls. University City's building code exempts this work: you do not need a permit. Why? Because you're not changing the water-supply and drain infrastructure or the electrical load. The vanity swap, faucet replacement, and toilet replacement are considered maintenance and fixture-swapping, not plumbing alterations. You can tile directly over the existing framing (no new waterproofing required if the wall is interior and not adjacent to a shower). However, if you discover rotten wood, mold, or structural damage behind the vanity during demo, you'll want to stop and hire a contractor to assess whether the wall needs to be rebuilt — that work would require a permit. A practical warning: even though a permit is not required, you should still verify the plumbing work is done correctly (proper vent distance, trap arm slope, P-trap under the vanity) and have a rough plumbing inspection by a knowledgeable contractor or inspector before you close up the walls. The total cost is typically $2,000–$5,000 for materials and labor (vanity, faucet, toilet, tile, labor), with no permit fees. Timeline is 1-2 weeks of work with no building department involvement.

Scenario B

Tub-to-shower conversion with relocated drain — accessible bathroom renovation (south of Forest Park)

You're removing an existing bathtub and replacing it with a large walk-in shower in the same general location, but the drain must be relocated 18 inches to the side to make room for a bench seat in the shower. You're also installing a new ceiling exhaust fan (the old one is broken), adding a second GFI outlet for a towel warmer, and waterproofing the shower with a cement-board-plus-membrane system. This work requires a permit from University City because you're relocating a fixture drain (changing the plumbing infrastructure), adding a new exhaust fan (new electrical branch circuit and ductwork), adding electrical outlets (expanding the electrical load), and installing a new waterproofing assembly. The drain relocation means your plumber must verify the trap arm length from the new shower location to the existing vent stack; if it's over 40 inches (typical for a 2-inch shower drain), you'll need a secondary vent line, which adds complexity and cost. The new exhaust fan must be sized at 50-75 CFM and ducted to the roof with insulation; this requires a separate plan showing fan location, duct routing, and roof penetration detail. The waterproofing assembly must be specified on your permit plan (e.g., 'Schluter Kerdi membrane with trowel-applied adhesive, or equivalent'). The second GFI outlet must be shown on an electrical plan with AFCI protection for the entire bathroom circuit. University City will require a full set of plans: floor plan showing fixture locations, plumbing plan with trap arm and vent routing, electrical plan showing outlets and circuits, and a detail section showing the waterproofing assembly. Plan review will take 10-14 days, and you'll likely get one round of comments (usually about waterproofing detail, duct termination, or trap arm routing). The permit fee is $500–$700 based on an estimated cost of work of $8,000–$12,000. Inspections are rough plumbing (drain and vent in place), rough electrical (wiring and exhaust fan wired), and final (all fixtures and fan operational, waterproofing verified, electrical covers on). Total timeline is 4-6 weeks from permit to final inspection, with work typically taking 2-3 weeks on site.

Scenario C

Wall removal and complete reconfiguration — split bathroom into two separate rooms (near Washington University campus)

You're opening up a doorway between two separate rooms and removing part of a wall to create a larger primary bathroom and a separate powder room. This involves demolishing a stud wall (non-load-bearing, but you must verify), relocating the main toilet drain 15 feet to a new location in the corner of the expanded bathroom, relocating the shower drain 12 feet to the opposite corner, adding new hot and cold supply lines to both new fixture locations, installing a new GFCI circuit for each room, installing two exhaust fans (one in the primary bath, one in the powder room), and rebuilding the wall opening with new framing and a header. This is a major remodel that absolutely requires a permit from University City. The scope triggers multiple code requirements: wall demolition and structural review (is the wall load-bearing? if yes, you need a structural engineer and a beam, adding $2,000–$4,000 in cost), drain relocation with trap arm verification for both fixtures (the 15-foot and 12-foot runs must have proper slope and vent distance, likely requiring a new 3-inch vent stack or relief vents), new supply-line routing (hot and cold to each fixture, with proper pressure-reducing valves and shut-offs at the main), electrical plan for two separate GFCI/AFCI circuits, and two exhaust fan plans with ductwork and roof terminations. University City will require a full set of permit plans: architectural floor plan showing wall demolition and new framing, structural plan if load-bearing, plumbing plan with supply and waste routing, electrical plan with circuits and GFCIs, and details for ductwork and vent terminations. Plan review will take 15-21 days, with multiple rounds of comments likely (wall framing, vent stack sizing, trap arm routing, electrical circuit separation). If the wall is load-bearing, you'll need a structural engineer's stamp, adding 2-4 weeks to the process. The permit fee is $700–$1,200 based on an estimated cost of work of $15,000–$25,000 (structural design $800–$1,500, plumbing $3,000–$5,000, electrical $1,500–$2,500, framing and finishes $10,000–$16,000). Inspections include rough framing (wall demolition and new framing), rough plumbing (main supply and waste), rough electrical (circuits wired), rough HVAC (exhaust fans installed), drywall and substrate, and final. Total timeline is 8-12 weeks from permit to final inspection, with on-site work typically 4-6 weeks. This is a project where you should hire a licensed general contractor to manage permitting, coordination, and inspections; trying to DIY-permit a wall removal often leads to rejection or stop-work orders.

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Waterproofing standards in University City: why the city is strict about shower assemblies

University City sits in the humid subtropical transition zone of the St. Louis metro area, with average annual humidity around 65-70% and frequent rain in spring and fall. This climate is ideal for mold growth, and bathroom water intrusion is one of the leading causes of mold claims in older homes. The city's Building Department has responded by enforcing a tighter waterproofing standard than some neighboring jurisdictions: any new shower or tub enclosure must have a specified waterproofing assembly shown on the permit plan, typically cement board (minimum 1/2 inch Durock or equivalent) plus a sheet or liquid-applied membrane (Kerdi, RedGard, Aqua Defense, or equivalent). This is not left to field judgment or 'best practice' — it's a permit requirement.

The code citation is IRC R702.4.2, which requires showers and tub enclosures to have a water-resistant or waterproof backing material and a water-resistant membrane. University City's interpretation adds specificity: you cannot use standard drywall with a plastic vapor barrier and assume it's waterproof. The city's plan reviewer will ask you to specify the membrane brand, thickness, and installation method (e.g., 'Schluter Kerdi membrane installed per manufacturer's instructions with Kerdi-Fix trowel-applied adhesive'). If you don't specify this upfront, your permit application will be marked 'incomplete' and returned for revision — a 5-7 day delay.

The practical impact on cost: a cement board plus membrane system adds $200–$400 to a shower remodel compared to basic tile-over-drywall. However, the cost of mold remediation (removal of affected framing, HVAC cleaning, remedial work) is $3,000–$10,000 per affected room. The city's strict requirement is a form of loss prevention. If you're doing a shower remodel without moving the drain or walls (Scenario A — the exemption case), you're not required to upgrade the waterproofing, but it's worth doing anyway. If you're doing a tub-to-shower conversion (Scenario B), it's mandatory.

Ventilation and humidity control: exhaust fan sizing and ductwork in University City bathrooms

A full bathroom remodel is an opportunity to upgrade or install proper exhaust ventilation, and University City enforces IRC M1505 strictly. The standard is simple: bathrooms must have either a window that opens to the outdoors (minimum 3% of floor area) or a mechanical exhaust fan that vents to the outdoors (not to the attic, crawl space, or interior soffit). A typical full bathroom (5x8 feet, 40 square feet) needs a fan rated at 50-75 CFM (cubic feet per minute) if under 50 square feet, or 1 CFM per square foot if over. A 60 square-foot bathroom needs a 60 CFM fan minimum. University City's inspector will ask to see the fan's nameplate CFM rating and will verify that the ductwork is rigid (no flex duct, which collapses and traps moisture) and routed directly to the roof or wall with at least 12 inches of clearance above the roof surface. The duct must be insulated (typically 1-inch foam jacket) to prevent condensation inside the duct, which contributes to mold and ice damming in winter.

A common mistake is venting the exhaust fan into the attic or soffit, assuming it will dry out. In University City's humid climate, attic moisture is a serious problem, especially in older homes with poor attic ventilation. If your attic duct doesn't penetrate the roof, the inspector will flag it and require you to reroute. The cost of rerouting an exhaust fan duct from attic termination to roof penetration is $300–$600 in materials and labor. Plan the fan location and ductwork routing before the permit plan is submitted; if you plan to locate the fan in a corner far from the existing vent line, you'll need to run ductwork 20+ feet, which may require additional supports, insulation, and a roof penetration plan. Ducts longer than 25 feet may require a larger fan or a booster fan to maintain CFM.

City of University City Building Department
8001 Natural Bridge Road, University City, MO 63121
Phone: (314) 505-8600 (verify current number with city website) | https://www.universitycitymo.gov/ (check for permit portal or submission instructions)
Monday-Friday 8:00 AM - 5:00 PM

Common questions

Do I need a permit if I'm just replacing my toilet, vanity, and faucet in the same location?

No. Fixture replacement in place (same location, same drain/supply lines) is exempt from permitting in University City. However, if any of the existing plumbing is damaged during removal and needs to be repaired or extended, that repair work does require a permit. If you're unsure about the condition of the existing lines, it's worth having a licensed plumber inspect before you demo.

I want to convert my bathtub to a shower. Do I need a waterproofing plan, or can I just tile over the existing wall?

You need a permit and a waterproofing assembly plan. A tub-to-shower conversion changes the water exposure from a tub enclosure (lower splash risk) to a full shower enclosure (continuous water spray and splash). University City requires a detailed waterproofing specification on the permit plan, typically cement board plus a sheet or liquid-applied membrane. You cannot simply tile over the existing drywall without upgrading.

Can I move the toilet drain across the bathroom if I'm doing a full remodel?

Yes, but it requires a permit and the drain routing must comply with code. The trap arm (horizontal line from the toilet outlet to the vent) cannot exceed 6 inches in length, and the drain line must have proper slope (1/4 inch per foot) and venting. If your proposed location is far from the existing vent stack, you may need a secondary vent line or a relief vent. University City's inspector will verify trap arm routing on the rough-in inspection.

My bathroom doesn't have an exhaust fan. Do I need to install one if I'm remodeling?

Not if your bathroom has an exterior window that opens to the outdoors and is at least 3% of the bathroom floor area. If you don't have an operable window, IRC M1505 requires a mechanical exhaust fan vented to the outdoors. If you're already pulling a permit for other work (drain relocation, new electrical), adding an exhaust fan is a good idea for moisture control and typically adds only $300–$500 to the project cost.

What happens during the rough plumbing inspection for a bathroom remodel?

The inspector will verify that all drain and vent lines are in place, properly sloped (1/4 inch per foot), and vented according to code (trap arm distance, vent sizing, vent termination at the roof). You should schedule this inspection after the drain and vent are roughed but before they're covered by drywall or insulation. Call the city to schedule; inspections typically happen within 2-3 business days.

I'm planning a shower remodel with a tileable membrane. Does University City accept Schluter Kerdi, RedGard, or other brands, or do I need a specific product?

University City's code (IRC R702.4.2) does not mandate a specific product, but your permit plan must specify what you're using. Schluter Kerdi, Laticrete RedGard, Aqua Defense, and equivalent products are all acceptable. The key is to specify the product, manufacturer, and installation method on the plan. Once specified, the inspector will verify the product is what you installed.

How long does plan review take for a bathroom remodel permit in University City?

Most single-bathroom remodels with straightforward plumbing and electrical (no walls moved, no load-bearing changes) are reviewed within 5-7 business days. If there are comments or revisions required, resubmission and re-review typically takes another 3-5 days. Complex remodels involving wall demolition or structural changes may take 15-21 days. Submit your plans as early as possible to avoid delays.

Do I need separate permits for plumbing and electrical work, or one combined bathroom remodel permit?

University City allows one combined bathroom remodel permit that covers plumbing, electrical, and structural work. You submit one permit application with a complete set of plans (floor plan, plumbing plan, electrical plan, and details). This is faster than pulling separate permits and simplifies coordination with the inspector.

I have a pre-1978 home. Do I need to do anything special regarding lead paint before I remodel my bathroom?

Yes. Missouri law requires disclosure of lead hazards in homes built before 1978. The city's building permit will ask whether you're disturbing painted surfaces. If you are, you must provide the federal lead disclosure form to any contractors and follow EPA RRP (Renovation, Repair, and Painting) rules if lead is suspected: contain dust, use lead-safe practices, and dispose of waste properly. Hire an RRP-certified contractor if you're uncertain.

What is the permit fee range for a typical full bathroom remodel in University City?

Permit fees are typically $400–$800 for a standard bathroom remodel, based on the estimated cost of work (usually 1.5-2% of valuation, with a minimum base fee). A remodel estimated at $10,000–$15,000 in cost will incur a fee around $500–$700. Call the Building Department or check the permit portal for the exact fee schedule.

Disclaimer: This guide is based on research conducted in May 2026 using publicly available sources. Always verify current bathroom remodel (full) permit requirements with the City of University City Building Department before starting your project.

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