Bathroom Remodel Permit in Katy, TX (2026)

Research by DoINeedAPermit Research Team · Updated May 2026

The Short Answer

A full bathroom remodel in Katy requires a permit if you relocate any plumbing fixtures, add electrical circuits, install a new exhaust fan, convert a tub to shower, or move walls. Surface-only work (tile, vanity swap in-place, faucet replacement) is exempt.

Katy operates under the International Building Code as adopted by the State of Texas, but the city's Building Department enforces its own plan-review process and fee schedule that differs meaningfully from neighboring Houston and Pearland. Katy requires all bathroom plumbing and electrical work to be submitted for plan review before any work begins — there is no over-the-counter permitting for fixture relocation or new electrical circuits. The city's online permit portal (accessible through the Katy city website) requires PDF submittals of plumbing and electrical plans showing GFCI/AFCI protection, fixture locations, and exhaust-duct termination; incomplete submittals are common rejection points and add 1–2 weeks to review. Katy's service area straddles climate zones 2A (coastal humidity, lower frost depth) and 3A (central Texas, 12–18 inch frost), which affects waterproofing assembly specs for shower/tub conversions — the city's inspectors will flag cement-board-only installations without proper membrane systems per IRC R702.4.2. Because Katy sits on expansive Houston Black clay and caliche soils, some inspectors cross-check drainage slopes and trap-arm lengths more rigorously than neighboring jurisdictions. Owner-occupant remodels are permitted under Texas Property Code, but you must sign the permit application as owner-builder; contractor-only work requires a licensed plumber and electrician.

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

Stop-work order from Katy Building Department carries $500–$1,500 penalty, plus mandatory permit re-pull at double the original fee ($400–$1,600 total permit cost).
Insurance claim denial for water damage or electrical fire if unpermitted bathroom work is discovered during a loss investigation; homeowner liable for full repair cost.
Title/resale disclosure hit — Texas Property Code requires seller disclosure of unpermitted work; buyer can demand repair or price reduction (typically 5–15% of home value for major systems).
Lender or refinance blockage — mortgage underwriters and appraisers flag unpermitted bathroom electrical or plumbing work; loan approval delayed or denied until work is legalized ($3,000–$8,000 to bring up to code after the fact).

Katy full bathroom remodels — the key details

The City of Katy Building Department enforces the 2015 International Building Code (IBC) as adopted by Texas, with local amendments primarily around drainage, GFCI/AFCI electrical protection, and waterproofing assembly documentation. Per IRC P2706, all drainage fittings in a bathroom must meet minimum slope (1/4 inch per foot) and trap-arm length (limited to 6 feet horizontal on a 2-inch drain, 8 feet on a 3-inch); Katy inspectors measure these on rough-in inspections and commonly reject plans that don't show trap-arm dimensions. The city requires all bathroom electrical circuits to include GFCI protection per IRC E3902 — this applies to all receptacles within 6 feet of a sink, tub, or shower. If your remodel adds a new circuit or extends existing circuits, you must submit a one-line electrical diagram showing breaker panel, circuit numbers, load calculations, and GFCI/AFCI locations; submittals without this detail face automatic rejection. Many homeowners and unlicensed contractors assume a simple outlet addition doesn't need a permit; Katy's plan-review staff will cite you if GFCI protection is not clearly marked on the electrical plan. Lead-paint rules apply if your home was built before 1978; the city does not enforce lead-paint disclosure, but if you hire a contractor, federal law (40 CFR 745) requires lead-safe work practices and documentation.

Exhaust fan installation or relocation is a common trigger for permit requirement in Katy. Per IRC M1505, all bathrooms must have mechanical ventilation (50 CFM minimum for a standard bathroom, 100 CFM for a bathroom with a tub and shower). If you are installing a new fan, replacing an existing fan with a ductless recirculating unit, or relocating ductwork, you must show the exhaust-duct route, diameter (typically 3 or 4 inches), and termination point on your plan. The city inspector will verify that the duct terminates outside the building envelope, not into an attic or soffit; ductless recirculating fans (which filter and return air indoors) do not meet Katy code and will fail inspection. Many DIY remodelers underestimate the duct-routing requirement — if you terminate a dryer vent into the bathroom to save ductwork cost, the inspector will red-tag the work and require removal. Katy's humid subtropical climate (2A/3A zones) makes proper exhaust ventilation critical to prevent mold; the city takes this seriously and often performs a final inspection specifically to verify duct termination.

Tub-to-shower conversions and shower waterproofing are high-risk areas for permit rejection in Katy. IRC R702.4.2 mandates a waterproofing membrane behind all shower walls and a sloped, impermeable base pan; the code does not specify a single method, but Katy inspectors expect one of three assemblies: (1) cement board + sheet membrane + tile, (2) foam-core pre-fab shower pan + cement board, or (3) rigid waterproofing sheet + tape seams. If your plan shows only cement board and tile without a membrane layer, the inspector will reject it as non-compliant. Many remodelers use drywall behind the shower or rely on grout alone, neither of which meets code. The city's online plan-review portal allows you to upload a detail drawing or product spec sheet showing your waterproofing system; this reduces rejection risk significantly. If you are converting a bathtub to a walk-in shower, the new drain location may require relocation of the P-trap and vent stack, which triggers plumbing plan review. Tub-to-shower conversions on the second floor sometimes require structural floor reinforcement if you are changing the wet area footprint; this is determined during plan review and may add 1–2 weeks.

Katy's permit fee structure is based on estimated project valuation. The city charges approximately $15–$25 per $1,000 of estimated construction cost for a plumbing/electrical remodel; a $10,000 bathroom remodel typically costs $150–$250 for the permit itself, plus $50–$100 for each additional inspection (rough plumbing, rough electrical, final). If your plan is rejected and resubmitted, you pay a re-review fee of $25–$50. The city's online portal shows fee schedules, but many homeowners discover late that inspections are not bundled — you pay per-inspection, which can total $200–$500 for a full gut remodel with all four inspections (rough plumbing, rough electrical, framing/drywall, final). Plan review typically takes 2–3 weeks for a standard remodel; if the plumbing plan shows trap-arm violations or the electrical plan lacks GFCI documentation, add another 1–2 weeks for resubmittal. Expedited review (5–7 business days) is available for an additional 50% fee, but it is rarely worth the cost for a residential bathroom.

Owner-builder permits are allowed in Katy for owner-occupied homes per Texas Property Code § 432.007. You must reside in the home and sign the permit application as the responsible party; you are then liable for all code compliance and must pass all inspections personally. Many owner-builders assume they can hire a licensed plumber to do plumbing-only and handle electrical themselves — this is not permitted. If you are pulling a permit as owner-builder, all work (plumbing, electrical, framing) must be performed by you or a single licensed contractor under your supervision; mixing and matching licensed trades without a general contractor license is a code violation. The city will require proof of ownership (deed or current mortgage statement) and a Texas ID matching the property address. If you later sell the home and disclose that you performed unpermitted work yourself, the buyer's lender may require an engineer's certification or forced correction before closing — budget an additional $2,000–$5,000 for post-facto remediation.

Three Katy bathroom remodel (full) scenarios

Scenario A

Vanity and toilet swap in-place, new tile floor, no plumbing or electrical relocation — Katy subdivision ranch

Your 1970s ranch has a standard 5x8 foot bathroom. You remove the existing vanity and toilet, install a new 36-inch vanity and a new low-flow toilet in the exact same locations, and replace the floor tile. The drain and supply lines remain untouched, the electrical outlet is not moved, and no new circuits are added. Under Katy code, this is surface-only work and does not require a permit. You do not need to file any plans, pay permit fees, or schedule inspections. However, if you discover during demolition that the existing drain line has a broken trap or P-trap and needs replacement, you must stop work and pull a plumbing-only permit before proceeding; many homeowners discover this mid-project and face a 2-week delay. A new toilet in the same flange location is exempt, but if the flange is below the finished floor or the wax ring is missing, the new toilet will rock and fail — this is not a code issue but a workmanship issue and will not be caught by the city. Your new vanity cabinet may have a different drain height; if you need to adjust the P-trap arm to meet the new sink location, you cross into plumbing-relocation territory and will need a permit at that point. Total cost for DIY vanity and tile: $1,500–$3,500 (materials and labor if hiring a handyman). If you hire a licensed plumber for the vanity hookup, they may recommend a permit to cover themselves; this is unnecessary for in-place work but shows contractor caution.

Scenario B

Relocate toilet to new wall, new drain line, GFCI outlet added, existing tub stays — Katy central bathroom remodel

Your bathroom has a toilet on the east wall and you want to move it to the north wall to accommodate new layout. This requires a new drain line, vent stack adjustment, and new supply lines — all of which trigger a plumbing permit. Your existing electrical outlet is 8 feet from the tub and does not have GFCI; you add a new GFCI outlet near the sink. The new electrical circuit and GFCI protection require an electrical permit. You must submit a two-page plumbing plan showing the new toilet location, drain-line route, trap-arm length (measured), vent-stack connection, and new supply lines. You must submit an electrical one-line diagram showing the breaker panel, the new 20-amp circuit, and GFCI protection on the outlet. Katy Building Department processes both permits together (combined fee $250–$400 based on $8,000–$12,000 valuation). Plan review takes 2–3 weeks; if your plumbing plan does not show trap-arm length or vent-stack connection, expect a rejection and 1-week resubmittal delay. Once approved, you schedule rough-plumbing inspection (city inspector checks drain slope, trap-arm length, vent termination, supply-line pressure at 80 psi) and rough-electrical inspection (GFCI outlet testing, circuit breaker label verification). Both inspections typically occur within 3–5 business days of notification. Final inspection happens after all work is complete (typically 1–2 weeks after rough inspections). Total project cost $8,000–$15,000 (licensed plumber $3,500–$6,000, licensed electrician $1,500–$3,000, permits $250–$400). If the plumber is not licensed or the electrician is unlicensed, Katy will issue a stop-work order and require the work to be undone or completed by a licensed trade; re-permitting will cost $400–$600 in addition to the original permit fee.

Scenario C

Full gut remodel — tub to shower conversion, new vanity location, new exhaust fan with ductwork, wall moved to enlarge space — Katy older home renovation

You own a 1950s Katy home and are doing a major bathroom remodel. You are removing the existing cast-iron bathtub and converting to a walk-in shower (new drain location, waterproofing membrane required). The vanity is moving from the south wall to the east wall (new drain, supply, and electrical outlet). An existing exhaust fan is being replaced with a new larger fan and ductwork is being rerouted to exit through the side wall instead of the attic. A non-load-bearing wall separating the bathroom from the adjacent hallway is being partially removed to enlarge the bathroom footprint. This triggers plumbing, electrical, structural, and HVAC permits (or combined building permit with multiple trade scopes). Your plumbing plan must show: (1) shower base location, drain slope, trap-arm length, vent-stack route; (2) new vanity drain and supply; (3) waterproofing detail (cement board + sheet membrane or equivalent, per IRC R702.4.2); (4) old tub drain capped or redirected. Your electrical plan must show: (1) new outlet near vanity with GFCI; (2) exhaust fan circuit and switch location; (3) any new lighting circuits. Your framing plan (or structural certification) must show the wall removal and any header sizing if structural load is present. Your HVAC plan must show exhaust-duct diameter, route, and termination point outside the building envelope. Katy requires all four trade submittals before issuing a combined permit. Plan review typically takes 3–4 weeks due to multiple scopes; waterproofing detail rejections are common (if the spec is unclear, the city will request a product data sheet). Once approved, inspections occur in sequence: rough plumbing (3–5 days), rough electrical (3–5 days), framing (if structural changes made), drywall (optional if not full interior finish), final (1–2 weeks after all rough inspections). Total permit cost $400–$800 based on $15,000–$25,000 valuation. Licensed plumber, electrician, and contractor (or structural engineer for wall removal) are mandatory. If you attempt this without permits and the city discovers unpermitted structural work (wall removal), the penalty escalates to $1,500–$3,000 plus forced removal or engineer certification at your cost ($2,000–$4,000). Total project cost $15,000–$35,000 including all trades and permits.

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Waterproofing and shower conversion in Katy's humid climate

The base pan itself is a common failure point in Katy inspections. If you use a prefab pan, it must be rigid enough to support tile and body weight without flexing; a pan that rocks or sounds hollow when tapped will fail. If you build a custom pan with a liner, you must use a sloped mud bed (1:12 ratio) and a secondary drain if the pan is larger than 32 square feet (per IRC P2717). Many remodelers assume they can use a simple vinyl liner in a wooden frame — this is not code-compliant in Katy and will fail the rough inspection. A proper custom pan consists of: concrete mud bed on a sloped substrate, primary drain through the pan, secondary drain (weep holes or secondary line) if required, and a sheet waterproofing membrane over the entire pan (including 12 inches up the walls). If you are uncomfortable specifying this level of detail, hire a plumber with shower-installation experience; the permit plan-review staff will accept a licensed plumber's stamp on the waterproofing detail. Once the pan and membrane are installed, the rough plumbing inspection checks for proper slope, drainage function, and secondary drain placement before any tile is laid. If the inspector finds the pan is not sloped correctly, you must remove the tile, correct the slope, replace the membrane, and re-tile — a costly rework. Katy's inspector notes often cite IRC R702.4.2 and ASTM C627 (tile installation standards) when rejecting waterproofing installations.

GFCI and AFCI requirements for Katy bathroom electrical work

AFCI protection (Arc Fault Circuit Interrupter) is required in bedrooms and, increasingly, in bathrooms and other areas per the 2023 NEC update; Katy Building Department may or may not enforce full AFCI for bathrooms depending on which code edition they have adopted (verify with the city). An AFCI detects dangerous arcing in wiring and trips the breaker; it is distinct from GFCI (which protects against ground faults). If your electrical plan includes new circuits in the bathroom or adjacent spaces, your electrician should include AFCI protection on those circuits to future-proof the installation and avoid a rejection if Katy's code has been updated. Many residential electricians bundle GFCI and AFCI on the same breaker (a combination GFCI/AFCI breaker costs $50–$75 and covers both requirements). When scheduling the rough electrical inspection, the inspector will test all GFCI and AFCI outlets with a test device; if any fail to trip or reset properly, the work is flagged for repair. The final inspection re-tests all GFCI/AFCI protection before the permit is closed out. This testing is non-negotiable and is a standard part of every bathroom electrical inspection in Katy. If you hire an electrician, ensure they provide a written statement that all work is GFCI/AFCI compliant per code; many disputes arise when homeowners discover mid-project that the electrician did not install GFCI protection and the plan review flagged it.

City of Katy Building Department
Katy City Hall, 901 Ave D, Katy, TX 77493
Phone: (281) 391-4800 (main) — ask for Building Permits | https://www.katytx.gov (search 'Building Permits' or 'Permit Portal')
Mon–Fri, 8:00 AM–5:00 PM

Common questions

Do I need a permit if I'm just replacing my bathroom faucet or showerhead?

No. Replacing a faucet, showerhead, or toilet in the same location without moving the supply or drain lines does not require a permit in Katy. If the faucet is a new finish (brushed nickel vs. chrome) or a different cartridge type, it is still surface-only work. However, if you discover the old valve is leaking or the trim ring must be removed to access the rough-in, consult a plumber; any work inside the wall cavity may trigger a permit if the valve cartridge is being replaced and the rough-in is exposed.

Can I pull a permit myself as an owner-builder, or do I have to hire a contractor?

You can pull a permit as owner-builder if you are the homeowner and occupy the property. You must sign the permit application, provide proof of ownership, and assume responsibility for code compliance. All work must be performed by you or a single licensed contractor (plumber, electrician) under your supervision; you cannot mix unlicensed work with licensed trades without a general contractor license. Katy will require your Texas ID, deed or mortgage statement, and verification that you reside at the address. Many homeowners hire a licensed plumber for plumbing work and an electrician for electrical, then pull the permit themselves for framing or finish work — this is permitted, but both trades must be licensed.

How long does plan review take in Katy, and can I expedite it?

Standard plan review takes 2–4 weeks depending on project complexity. A simple toilet relocation with new GFCI outlet typically clears in 2–3 weeks. A full bathroom gut with shower conversion, wall removal, and new exhaust ductwork can take 3–4 weeks if rejections occur. Expedited review (5–7 business days) is available for an additional 50% fee ($125–$200 for a standard permit); many homeowners find this not worth the cost. Rejections are common if waterproofing details are missing, trap-arm lengths are not shown, or GFCI labeling is unclear — plan for a 1-week resubmittal delay if your first plan is rejected.

What happens at the rough plumbing and electrical inspections?

Rough plumbing inspection (after walls are framed and pipes are run, before drywall) checks: drain-line slope (1/4 inch per foot), trap-arm length (measured and verified), P-trap and vent-stack connections, supply-line pressure (80 psi test), and proper fixture rough-ins. Rough electrical inspection (after wiring is run, before drywall) checks: all circuits are properly sized and breaker-protected, all GFCI/AFCI outlets are installed and functional (tested with GFCI tester), switch and outlet boxes are correctly positioned, and all work complies with the approved plan. Both inspections are pass/fail; if the inspector finds violations, work is flagged and you must correct before proceeding. The inspector will not approve any work that violates code, and re-inspection costs are absorbed into your original permit.

Do I need to worry about lead paint in my 1960s bathroom?

If your home was built before 1978, lead paint may be present. Federal law (40 CFR 745) requires a contractor to follow lead-safe work practices (containment, HEPA vacuuming, disposal) when disturbing painted surfaces. The City of Katy does not issue lead-paint permits or conduct lead-paint inspections, but if you hire a licensed contractor, they are legally required to provide lead-paint disclosure and follow federal protocols. If you are doing the work yourself as an owner-occupant, you are exempt from federal lead-paint rules, but EPA guidance recommends taking precautions (wet-sanding, HEPA-filtered vacuum, containment). Lead is not a structural code issue and will not cause a permit rejection, but it is a health and legal issue that must be addressed if a contractor is involved.

What if I find mold or water damage behind the walls during demolition?

Stop work and notify the city. If the moisture damage is extensive (more than 10% of wall area), the city may require a moisture assessment or structural inspection before you proceed. Mold remediation is not covered by building permits, but moisture intrusion (from a plumbing leak or roof leak) may require the source to be identified and corrected before bathroom work resumes. If the mold is caused by previous bathroom water intrusion (cracked grout, failed waterproofing), you must correct the waterproofing on the new shower to prevent recurrence. Many homeowners discover hidden mold during bathroom demos and delay the project by 2–4 weeks for remediation; budget for this possibility if your home is older.

Can I use a recirculating (ductless) exhaust fan instead of venting outside?

No. Per IRC M1505, all bathroom exhaust fans must duct outside the building envelope. A ductless recirculating fan that filters and returns air indoors does not meet Katy code and will fail the final inspection. The exhaust duct must terminate on an exterior wall or roof (not in an attic, soffit, or crawlspace). If ducting outside is difficult, you can install a damper or insulated ductwork to improve efficiency, but the fan must exhaust outdoors. Many DIY remodelers attempt ductless fans to save time and money; the city inspector will red-tag this and require the work to be corrected.

How much will the permit cost for my bathroom remodel?

Katy charges approximately $15–$25 per $1,000 of estimated construction cost. A $10,000 bathroom remodel costs $150–$250 for the permit. A $20,000 remodel costs $300–$500. Additional inspection fees (rough plumbing, rough electrical, final) are $50–$100 each, adding $200–$400 total for a full-scope remodel with 3–4 inspections. If your plan is rejected and resubmitted, expect a $25–$50 re-review fee. Expedited review (5–7 days) adds 50% to the base permit fee. Always confirm the exact fee with the city before pulling the permit; cost estimates on the city website may differ from what the permit counter quotes.

What is the most common reason Katy rejects bathroom permit plans?

Missing or unclear waterproofing detail for shower/tub conversions. Inspectors commonly reject plans that don't specify the waterproofing system (cement board + membrane, prefab pan, or rigid sheet). The second most common rejection is missing GFCI labeling on electrical plans or trap-arm length not shown on plumbing plans. Third is exhaust-duct termination not clearly marked as 'outside building envelope.' Submitting detailed one-page drawings for each trade (plumbing, electrical) with clear labels and product specs reduces rejection risk significantly. Many homeowners underestimate the level of detail Katy's plan reviewers require; a vague sketch will not pass.

Do I need a separate permit for a new exhaust fan, or is it included in my plumbing permit?

Exhaust fan installation is typically included in the electrical or combined building permit, not a separate permit. However, if you are only replacing a fan in the same location with the same ductwork, no permit is required — this is considered maintenance. If you are installing a new fan, relocating ductwork, or changing duct diameter, you must include the exhaust-fan scope in your electrical permit or combined building permit. The plan must show the duct route, diameter, and termination point outside the building envelope. Katy will not issue a separate HVAC-only permit for residential exhaust fans; it is bundled with electrical or building permits.

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 Katy Building Department before starting your project.

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