Bathroom Remodel Permit in Webster Groves, MO (2026)

Research by DoINeedAPermit Research Team · Updated May 2026

The Short Answer

A full bathroom remodel requires a permit in Webster Groves if you relocate any plumbing fixture, add new electrical circuits, install a new exhaust fan, or alter walls. Surface-only work—tile, vanity, or faucet replacement in place—is exempt.

Webster Groves Building Department enforces Missouri's adoption of the 2021 International Building Code and 2020 National Electrical Code. Unlike some St. Louis County municipalities that have adopted older code cycles or granted broad owner-builder exemptions for cosmetic work, Webster Groves applies strict fixture-relocation rules: any movement of a toilet, sink, or drain line requires full plumbing permitting and inspection, per IRC P2706 requirements on trap-arm length and drainage slope. The city's online permit portal (managed through the Webster Groves municipal website) allows expedited over-the-counter plan review for small-scope projects but flags any bathroom work involving fixture movement or electrical circuits for full review, typically adding 2-5 weeks. Webster Groves also enforces local amendments requiring GFCI protection on all bathroom outlets (NEC 210.8) and specifies that exhaust-fan ducting must terminate outside the home, with ductwork sized per IRC M1505—this last detail is a common rejection point for DIY applicants who undersize or terminate into an attic. Lead-paint disclosure and testing apply to all pre-1978 homes, adding compliance cost ($100–$300 for abatement consultation) to older renovation budgets.

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

Stop-work orders carry a $250–$500 fine in Webster Groves, plus mandatory double-fee penalty ($400–$1,600 total permit cost) when you pull the permit retroactively.
Insurance claim denial on water damage or electrical fire—insurers routinely deny bathroom water-damage claims if unpermitted plumbing work is discovered during investigation.
Resale disclosure hit: Missouri Residential Real Property Condition Disclosure Statement (MRPD) requires seller to disclose all unpermitted work; undisclosed bathroom remodels can trigger buyer rescission or post-closing litigation costing $5,000–$15,000 in legal fees.
Lender/refinance block: If you refinance or seek a home-equity line of credit, appraisers verify permit history; unpermitted bathroom work can reduce appraised value by 3-8% or cause loan denial outright.

Webster Groves full bathroom remodels—the key details

Permit requirement hinges on what you're changing, not the budget. If your bathroom remodel is limited to replacing the toilet in place, swapping out a vanity for a new one in the same footprint, retiling walls, or upgrading the faucet without moving the supply lines, you do not need a permit. However, moving any fixture—relocating the toilet to a new wall, replacing a pedestal sink with a vanity in a different location, converting a tub to a shower (which changes the waterproofing assembly under IRC R702.4.2), or extending drain lines—triggers the full permit cycle. Adding new electrical circuits, installing a new exhaust fan, or removing/relocating interior walls also requires permitting. Webster Groves Building Department applies this threshold consistently across all residential remodels in the city; there is no owner-builder exemption for bathroom work, though the city does allow owner-builders to pull permits for their own owner-occupied homes if the total project value is under $50,000.

Plumbing code is the thorniest part of a full remodel. IRC P2706 specifies that the trap arm (the run of pipe from the P-trap to the stack) cannot exceed 6 feet horizontally or 12 inches in vertical rise without additional venting—and Webster Groves inspectors enforce this strictly because the city's loess-based soil and 30-inch frost depth create moisture problems if drains back up or aren't properly graded. If your bathroom is on a second floor, the drain line may need to run a considerable distance to reach the stack, and trap-arm length violations are a top plan-review rejection. You'll need a licensed plumber to certify drain routing on your permit application. All water-supply lines must be at least 6 inches below grade (frost protection per local amendments to IRC R403.1) or insulated if run in interior walls—this is especially relevant in Webster Groves' climate zone 4A. Pressure-balanced or thermostatic mixing valves are required on all new shower installations (NEC 2020, per local adoption) to prevent scalding; this is often overlooked by DIY designers but will be flagged in plan review.

Electrical and ventilation code is dense but non-negotiable. Every bathroom outlet must be GFCI-protected (NEC 210.8(A)); if you're adding a new circuit for a heated towel rack, ventilation fan, or additional outlets, that circuit must be on its own 20-amp breaker and clearly labeled on the electrical plan. All bathroom lighting must be on a separate 20-amp circuit from outlets (NEC 210.11(C)(3))—this is a common mistake that delays plan approval. New exhaust fans require ducting to the exterior (not to an attic or soffit per IRC M1505.3), and ductwork must be sized per fan CFM—a typical bathroom exhaust fan is 50-80 CFM, requiring 4-inch ductwork; oversizing the duct or undersizing the fan's output is a rejection trigger. Ductwork must also be sealed and insulated if it runs through unconditioned spaces (per local amendments to IRC M1601.1), which adds cost but prevents condensation buildup in Webster Groves' humid summers.

Waterproofing assembly for tub-to-shower conversions or new showers is specify-it-or-die territory. IRC R702.4.2 requires a water-resistant barrier (cement board or Durock) plus a moisture barrier (liquid membrane or sheet membrane, such as Kerdi or RedGard). You must specify the exact product on your plan: 'CementBoard + RedGard liquid membrane' or 'Durock + Schluter-Kerdi,' and the membrane must extend 6 inches above the showerhead. Pre-formed shower pans (one-piece acrylic) are permitted as an alternative if they're factory-sealed and meet ASTM E413; however, custom tile showers require the full assembly on the permit. Inspectors will request product data sheets during plan review, and rough inspection will verify that the membrane is installed before tile is laid. Failing to specify a waterproofing system upfront is the #1 reason for bathroom plan rejections in Webster Groves.

Timeline and fees: Webster Groves charges permit fees on a sliding scale based on project valuation. A small bathroom remodel (≤$5,000) is typically $250–$350; mid-range ($5,000–$25,000) is $400–$650; larger remodels ($25,000+) may run $700–$800. Plan review takes 2-5 weeks if the city requests revisions (waterproofing specs, trap-arm routing, electrical GFCI labeling); over-the-counter approval for simple scopes (new vanity + tile, no fixture moves) can happen same-day. You'll need three inspections minimum: rough plumbing (after drain lines and supply lines are installed but before drywall), rough electrical (after circuits are run, before outlets/switches are installed), and final (after all finishes are complete and mechanical/electrical are live). Each inspection must be scheduled 24-48 hours in advance through the city portal or by phone. Expect total timeline from permit issuance to final sign-off to be 6-10 weeks if no significant revisions are needed.

Three Webster Groves bathroom remodel (full) scenarios

Scenario A

New vanity + tile resurfacing, same drain/supply locations—Lockwood neighborhood bungalow

You're ripping out an old pedestal sink and replacing it with a new vanity cabinet in the exact same footprint, retiling the shower surround with new cement board and waterproofing (but keeping the existing tub/drain), and upgrading the faucet. Because the drain line, supply lines, and trap arm stay in place, this is surface-only work. Webster Groves Building Department classifies this as cosmetic interior remodeling and does not require a permit. You can order materials, hire a contractor (or DIY the work), and complete the project without notification to the city. However, if the vanity weighs more than 40 pounds when installed or if you're replacing a pedestal sink with a wall-hung sink that requires new blocking in the wall, you should confirm with the city that structural reinforcement doesn't trigger plumbing code review—in most cases it won't, but the conservatively correct approach is a quick phone call to the building department before starting. Lead-paint disclosure still applies if the home was built before 1978; you must test and disclose, even though no permit is needed. Total project cost is typically $3,000–$7,000 (materials + labor); zero permit fees.

No permit required (surface-only resurfacing) | Lead-paint test recommended ($150–$300) | Cement board + RedGard waterproofing system required | Total out-of-pocket $3,000–$7,000 | No permit fees

Scenario B

Moving toilet to opposite wall + new exhaust fan with exterior duct—Teasdale Hills home, second-floor bathroom

You're moving the toilet 8 feet to the opposite wall (new drain line, new trap), adding a new exhaust fan with 4-inch rigid ductwork routed to an exterior soffit vent, and upgrading electrical service (15-amp fan circuit + new GFCI outlet circuit). This requires a full permit because fixture relocation and new exhaust fan both trigger plumbing and mechanical code review. You'll need a licensed plumber to design the new drain routing and certify that the trap-arm length doesn't exceed 6 feet horizontally from the P-trap to the stack—in a second-floor bathroom in Teasdale Hills (where stacks often run the length of the house), this is a critical calculation. The plumbing plan must show drain slope (minimum 1/4 inch per foot per IRC P2706) and clearly label the trap arm. Electrically, the exhaust fan circuit must be on a dedicated 20-amp breaker, separate from the bathroom outlet circuit, and the ductwork must be sized to match the fan's CFM rating (typically 50-80 CFM for a single-toilet bathroom); oversizing the duct to 6 inches or running it to the attic instead of an exterior vent will be flagged as a code violation. Waterproofing is not a new issue here (the tub stays in place), but the electrical and plumbing plans must be submitted to Webster Groves Building Department for 2-4 week review. Plan review will request product data for the exhaust fan, ductwork material (rigid aluminum or PVC preferred; no flexible ductwork per local adoption of IRC M1506.2), and the duct termination detail. Rough plumbing inspection happens after the new drain line is stubbed in; rough electrical inspection verifies the fan circuit wiring and GFCI outlet layout; final inspection confirms the exhaust fan is operational and ducting is sealed. Total cost is $6,000–$12,000 (plumbing + electrical + labor); permit fee is $400–$550.

Scenario C

Tub-to-shower conversion + wall relocation—Orchard Hill colonial, master bath renovation

You're removing the bathtub entirely, installing a large walk-in shower with a custom tile assembly, relocating the half-wall between the toilet and shower area to create an open layout, and adding a new vanity in the relocated space. This is a full structural and plumbing overhaul. Fixture relocation (drain/trap for the shower, toilet in new position), waterproofing assembly change (tub to shower per IRC R702.4.2), wall removal/relocation, and electrical additions (new outlet circuit for new vanity area) all require permitting. The permit application must include: (1) a framing plan showing wall relocation and any header/beam requirements (Webster Groves Building Department will want to confirm that removing the wall doesn't affect load-bearing capacity); (2) a plumbing plan with new drain routing, trap-arm length verification, and P-trap location relative to the stack (at 30-inch frost depth in Webster Groves' climate zone 4A, drain lines must be insulated or below-grade; interior wall runs must be protected); (3) a waterproofing specification for the shower (cement board + RedGard membrane, or Schluter-Kerdi system, with 6-inch membrane extension above showerhead); (4) electrical plan showing GFCI outlets, any new circuits for heated floors or towel racks, and lighting on a separate 20-amp circuit. Plan review will typically take 4-6 weeks because the structural and plumbing changes are interdependent (the framing inspector may need to verify that drain routing clears the relocated wall). Inspections will include: structural framing (after wall relocation, before drywall), rough plumbing (after drain/trap install), rough electrical (after circuits are run), drywall (to verify waterproofing membrane is in place before tile), and final. A pre-construction meeting with the building department is highly recommended to clarify the waterproofing assembly and wall relocation sequencing. Total cost is $12,000–$25,000+ (demolition, framing, plumbing, electrical, tile, finishes); permit fee is $700–$850.

Permit required (fixture relocation + wall change + waterproofing assembly change) | Framing plan with structural verification required | Licensed plumber + electrician required | Cement board + full waterproofing membrane system (Kerdi or RedGard) | New drain routing, trap-arm verification, frost-depth insulation required | Separate 20-amp circuits for outlets and lighting | Total $12,000–$25,000+ | Permit fee $700–$850 | Timeline 6-12 weeks with plan revisions

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Waterproofing assembly: the IRC R702.4.2 specification trap

More bathroom permits are rejected in Webster Groves over waterproofing assembly than any other single issue. IRC R702.4.2 specifies that showers and tub-shower combinations must have a water-resistant backing material (cement board, gypsum board rated for wet areas, or proprietary systems like Durock) plus a moisture barrier (liquid membrane, sheet membrane, or pan liner). The spec must be on your permit drawings; vague language like 'standard waterproofing' or 'Durock and sealant' will be flagged as insufficient. Webster Groves inspectors require product documentation: if you specify RedGard, you must provide the technical data sheet showing coverage rate, curing time, and compatibility with your tile adhesive; if you use Schluter-Kerdi, the spec must say 'Kerdi sheet membrane with sealed seams per Schluter instructions.' The membrane must extend at least 6 inches above the showerhead (to catch splash), and corners must be detailed with reinforced tape or corner profiles (Kerdi corners, not improvised mesh tape). During rough inspection, the inspector will pull back drywall or inspect the wall surface directly to verify the membrane is installed before tile is laid. This is not negotiable: if you tile over cement board without a liquid membrane, you will fail rough inspection and must remove tile, install membrane, and re-tile. Many DIY applicants think 'cement board + grout' is waterproofing; it is not. Cement board is water-resistant but not waterproof. The membrane is what prevents water from migrating into the framing.

One-piece acrylic or fiberglass shower pans are an alternative that can bypass the assembly requirement if they are factory-sealed and meet ASTM E413 specification. However, if you use a one-piece pan and then tile the walls above it, you still need the waterproofing membrane on those tiled walls. If you're installing a custom tile shower pan (sloped floor with linear drain), this is exponentially more complex: you need a sloped substrate (mortar bed or pre-sloped pan liner), a full membrane system (RedGard or Kerdi pan liner designed for floors), and proper slope (minimum 1/4 inch per foot toward the drain per IRC P2706). Webster Groves Building Department treats custom tile shower pans as a specialty trade requiring a licensed installer plan signed-off; many cities require a third-party inspection (Certified Aging in Place Specialist or equivalent) for tile-pan waterproofing due to failure rates. Budget conservatively: a properly detailed custom tile shower with waterproofing adds $2,000–$4,000 to a bathroom remodel. A one-piece acrylic surround adds $800–$1,500.

Lead-based paint is a secondary but real compliance requirement. All homes built before 1978 must have lead-paint testing and disclosure before renovation. Webster Groves requires a licensed lead-paint inspector (EPA RRP certified) to test walls/surfaces that will be disturbed (this includes bathroom fixtures and adjacent walls). Testing costs $150–$300; if lead is found, abatement must be done by a certified contractor (add $500–$1,500 for a small bathroom). If you do not test and lead is present, you can face state fines of $200–$500 and liability if occupants (especially children) are harmed. The disclosure is required even if the work is cosmetic and doesn't require a permit; the permit application process surfaces this requirement.

Electrical and exhaust-fan ductwork: separation and sizing rules

Bathroom electrical in Webster Groves follows NEC 2020 as adopted locally, with some strict enforcement of outlet/circuit separation that trips up many DIY applicants. Rule one: all bathroom outlets must be on a 20-amp GFCI-protected circuit; this circuit cannot serve any outlets outside the bathroom (NEC 210.8(A) and 210.11(C)(1)). Rule two: bathroom lighting must be on a separate 20-amp circuit from the outlets, and that lighting circuit can serve lights in adjacent spaces but not bathroom outlets. Rule three: any hardwired appliance (exhaust fan, heated towel rack, ventilation unit) requires its own dedicated circuit. So a typical bathroom remodel has at least three circuits: (1) bathroom outlet GFCI, (2) bathroom lighting, (3) exhaust fan. If you're adding a heated floor or towel rack, that is a fourth circuit. Each circuit must be clearly labeled on the electrical plan submitted to Webster Groves. During rough electrical inspection, the inspector will verify circuit separation by checking the panel (each breaker is dedicated and labeled), checking for GFCI outlets or breakers (GFI outlets protect downstream outlets; GFI breakers protect the entire circuit), and verifying that outlet spacing doesn't exceed 6 feet from a GFCI source in any direction (NEC 210.8(A)(1)). Any outlet you add in the bathroom must be within 6 feet of a GFCI; this includes new vanity areas, heated towel rack locations, etc.

Exhaust-fan ductwork is the second electrical pain point. IRC M1505 and M1506 require that exhaust fans be ducted to the exterior (not to an attic, crawl space, or soffit). ductwork must be sized to the fan's CFM rating: a 50-80 CFM fan (typical for a single-bathroom) requires 4-inch rigid ductwork; a 100+ CFM fan (required if the bathroom is over 100 square feet) requires 5-inch or 6-inch ductwork. The ductwork must be straight or minimize bends (each 45-degree bend = 10 linear feet of equivalent length; 90-degree bends = 20 linear feet). If your run is 20 linear feet with one 90-degree bend, equivalent length is 40 feet, which will require a fan rated for at least 40-foot run. Most DIY applicants undersize the ductwork or route it to a soffit vent (which is a code violation per local adoption of IRC M1506.2) and hit this during plan review or final inspection. Flexible ductwork is not permitted (per local amendment); only rigid metal or rigid PVC is allowed. Ductwork must be sealed at seams (foil tape or mastic, not caulk) and insulated if it runs through unconditioned spaces (R-6 minimum per local amendment to IRC M1601.1); this prevents condensation in Webster Groves' humid summers. The exterior termination must have a damper (spring-loaded or gravity, not a one-way flapper that sticks). A common rejection: applicants specify '4-inch flex ductwork to soffit vent.' This fails on multiple counts (flex not permitted, soffit not permitted, undersized for run length). Correct spec: '5-inch rigid metal ductwork with foil-sealed seams, insulated R-6, 20-foot run with one 90-degree elbow, terminating through roof with spring-damper vent.' Always request ductwork sizing from your HVAC contractor and include it on the permit plan.

If you're installing a bathroom exhaust fan for the first time (adding one where none existed), the fan must be manually operable via a switch (not motion-sensor only, though motion sensors can supplement) per NEC 210.70(A)(2). The switch must be in the bathroom, not in an adjacent space. If the bathroom has a window, the window must be on a separate operable control (you cannot have the window operation controlling the fan automatically). Many jurisdictions allow or even recommend humidity-sensor fans (fans that run automatically when humidity exceeds 60%), which are helpful in Webster Groves' climate but must still have a manual override. Specify the fan model and controller type on your permit; this matters because the inspector will verify the installation matches the plan during rough inspection.

City of Webster Groves Building Department
Webster Groves City Hall, Webster Groves, MO 63119 (contact through city website for exact building-department office address and hours)
Phone: (314) 963-5900 (main city hall number; request building department or permit office) | https://www.ci.webster-groves.mo.us/ (check city website for online permit portal or e-permitting system)
Monday-Friday, 8:00 AM - 5:00 PM (verify with city for permit-office specific hours and closure days)

Common questions

Do I need a permit if I'm just replacing my toilet and faucet in place?

No. Replacing a toilet, faucet, showerhead, or other fixture in its existing location without moving water supply or drain lines is cosmetic work and does not require a permit in Webster Groves. You can hire a plumber or do it yourself without notification to the city. However, if you are moving the toilet to a new location or extending drain/supply lines, a permit is required.

Can I do the bathroom remodel work myself, or do I have to hire licensed contractors?

Webster Groves allows owner-builders to pull permits for their own owner-occupied homes regardless of trade. However, Missouri law (and local amendments in some St. Louis County municipalities) may require that certain work—plumbing and electrical especially—be performed by licensed contractors or inspected by a master tradesperson. For a full bathroom remodel, it is safest to assume that plumbing and electrical work must be licensed; framing, drywall, tiling, and finish work can often be owner-built. Contact the Webster Groves Building Department directly to confirm whether your specific scope (e.g., running new drain lines, adding electrical circuits) requires a licensed contractor. Lead-paint work must be done by a certified contractor if lead is present.

What is the most common reason bathroom permits get rejected in Webster Groves?

Waterproofing assembly specification is the #1 rejection reason. If your permit plan does not clearly specify the waterproofing system (e.g., 'cement board + RedGard membrane' or 'Schluter-Kerdi'), the city will request revisions before proceeding. The second most common rejection is exhaust-fan ductwork routed to an attic or soffit instead of the exterior, which violates IRC M1506. Third is trap-arm length exceeding 6 feet without adequate venting or GFCI/AFCI circuits not clearly labeled on electrical plans. Submit detailed product specifications and drawings upfront to avoid delays.

How long does the permit review process take in Webster Groves?

Plan review typically takes 2-5 weeks for a full bathroom remodel with fixture relocation, electrical, and plumbing changes. If the city requests revisions (common on waterproofing or trap-arm routing), add 1-2 weeks per revision cycle. Once the permit is issued, actual construction can begin immediately, but you'll need to schedule three or more inspections (rough plumbing, rough electrical, final) at 24-48 hour intervals, adding 4-8 weeks to the total project timeline depending on inspection availability and any rework needed.

Are there any local amendments to the International Building Code that affect bathroom remodels in Webster Groves?

Webster Groves has adopted the 2021 International Building Code with local amendments that affect bathrooms specifically: frost-depth protection (drain lines must be insulated or below 30 inches), exhaust-fan ductwork must be rigid (not flexible) and terminated to the exterior with a damper, waterproofing membranes on shower walls must extend 6 inches above the showerhead, and GFCI protection is required on all bathroom outlets. These are more stringent than the model code in some areas, so confirm with the city before designing your electrical and plumbing plan.

What happens if I discover lead paint during my bathroom remodel?

If your home was built before 1978 and lead paint is present, federal law (EPA RRP Rule) requires that all disturbing activities stop, a certified lead-paint contractor be hired for abatement, and the work area be contained and cleaned. Abatement costs $500–$1,500 for a small bathroom. If you do not test and lead is found post-renovation (e.g., during a home inspection for resale), you face state fines and potential liability. Lead-paint testing before renovation is strongly recommended and is typically required by lenders and insurance.

If I convert my bathtub to a shower, do I need a new permit even if I'm keeping the drain in the same location?

Yes. A tub-to-shower conversion changes the waterproofing assembly from a tub surround (typically three walls with a tub pan) to a full shower assembly (sloped pan or acrylic base plus tiled walls with full membrane), which falls under IRC R702.4.2. Even if the drain stays in place, the fixture change and waterproofing system change require a permit and plan review in Webster Groves.

What is the permit fee for a full bathroom remodel in Webster Groves?

Permit fees are based on estimated project valuation: small remodels (≤$5,000) are $250–$350; mid-range ($5,000–$25,000) are $400–$650; larger projects ($25,000+) are $700–$850. The valuation includes labor and materials; the city calculates it using a cost-per-square-foot method or by comparing to similar projects. There is no separate inspection fee; the permit fee covers all three or more required inspections.

Can I use a fiberglass shower surround instead of tiling to avoid the waterproofing complexity?

Yes. One-piece acrylic or fiberglass shower surrounds that are factory-sealed and meet ASTM E413 specification are an alternative to custom tile; they do not require the same waterproofing assembly documentation. However, if you then add tile or wall finishes above the surround, those areas still require the full waterproofing system (membrane + substrate). A one-piece surround typically costs $800–$1,500 and simplifies the permit plan; custom tile adds $2,000–$4,000 but offers design flexibility.

Do I need a separate permit for the cosmetic bathroom work (tile, vanity, painting) that I'm doing at the same time as the structural work?

No. One permit covers the entire bathroom remodel, regardless of scope (structural, plumbing, electrical, cosmetic). You do not pull separate permits for each trade or phase. However, if you are doing the cosmetic work months later as a separate project, you may not need a permit for the cosmetic phase alone; the first permit (for fixture relocation, electrical, etc.) covers the structural and systems work.

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 Webster Groves Building Department before starting your project.

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