Research by DoINeedAPermit Research Team · Updated May 2026
The Short Answer
Any full bathroom remodel involving fixture relocation, new electrical circuits, exhaust fan installation, or wall changes requires a permit from the City of Cudahy Building Department. Surface-only cosmetic work (tile, vanity swap in place, faucet replacement) is exempt.
Cudahy, unlike some smaller Bay Area jurisdictions, enforces the full California Building Code adoption with active plan review and inspection timelines — you cannot pull a permit as a simple counter-service over-the-counter filing. All bathroom remodels that touch plumbing lines, electrical circuits, or structural framing must be permitted and inspected by the City of Cudahy Building Department. The city follows California Title 24 energy code amendments (required for exhaust fan CFM and GFCI/AFCI protection), and the Building Department will flag any shower waterproofing assembly that lacks manufacturer-specified membrane detail. Cudahy's online permit portal exists but is not a full-service e-filing system — you'll submit plans in person or by mail, and the city conducts a 2–5 week standard plan-review cycle. For pre-1978 homes (common in Cudahy's older neighborhoods), lead-paint disclosure and RRP-rule compliance are separate requirements on top of the building permit. Owner-builder permit is allowed under California B&P Code § 7044, but licensed plumbers and electricians are mandatory for their trades — you cannot self-perform plumbing or electrical work.

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

Cudahy full bathroom remodel permits — the key details

Cudahy enforces the 2022 California Building Code (or the most recent adoption at time of project), which means your bathroom remodel must comply with IRC (International Residential Code) sections adopted by the state. The three biggest code hooks for bathroom remodels are IRC P2706 (plumbing drainage and trap sizing), IRC M1505 (bathroom exhaust fan CFM and duct termination), and IRC R702.4.2 (shower/tub waterproofing assembly specification). If you are relocating any fixture — toilet, sink, shower valve, or tub drain — the trap arm (horizontal drain run before the vent) cannot exceed 42 inches (IRC P3105.1). Many homeowners underestimate this rule; a 50-foot run from a rear master bath to a side-yard stack requires redesign or a secondary vent. Any new electrical outlet, lighting circuit, or GFCI breaker must be shown on a plan, and the Building Department will verify that all bathroom circuits include either a GFCI receptacle or GFCI-protected breaker (NEC 210.8(A), adopted in California). If you are converting a bathtub to a shower (or vice versa), the waterproofing assembly changes, and you must specify the exact membrane system — cement board + redgard membrane, schluter kerdi, or a pre-fab shower pan — with manufacturer's installation documentation attached to the permit application.

Cudahy's Building Department does not offer same-day permit issuance for bathroom remodels; plan-review timelines typically run 2–5 weeks depending on completeness and whether the plans require structural or mechanical review. The department's online portal (accessible via the City of Cudahy website) allows you to check permit status and view plan comments, but initial submission still requires in-person or mailed documents. Fees for a full bathroom remodel are typically $300–$600 depending on the valuation of the work (usually calculated at 1–2% of the estimated construction cost). A $20,000 remodel would incur roughly $300–$400 in permit fees; a $40,000 remodel, $400–$800. Cudahy does not charge separate plan-review fees upfront, but if the plans are rejected and require resubmission, you will pay an additional $75–$150 resubmission fee. The permit is valid for 180 days; if you do not start work within that window, you must renew or re-pull (typically at no additional fee if the code hasn't changed).

Inspection sequencing for a full bathroom remodel typically follows this order: rough plumbing (before walls close), rough electrical (before drywall), framing (if walls are moved), drywall (final layer before tile/finish), and final inspection (after all fixtures are installed and operational). Rough plumbing inspection verifies trap sizing, slope (1/4 inch per foot minimum, IRC P2705.1), vent placement, and rough-in height of supply lines. Rough electrical inspection confirms GFCI/AFCI protection, correct wire gauge for circuits, outlet placement, and exhaust fan wiring. If you are moving walls, a separate framing inspection is required before drywall to verify structural integrity and waterproofing. Many Cudahy inspectors will waive the drywall inspection if the bathroom is a minor remodel (existing walls, no structural changes), but it is safer to request it if you are installing new waterproofing. Final inspection is mandatory and checks that all fixtures are operational, vent ductwork terminates outside (not in attic), and tiles/finishes are complete. Plan on 1–2 weeks between each inspection stage, so total project timeline (permit to final sign-off) is typically 4–8 weeks.

For pre-1978 homes in Cudahy (many Cudahy neighborhoods are 1960s–1980s construction), lead-paint disclosure and RRP (Renovation, Repair, Painting) rule compliance are mandatory separate from the building permit. If your bathroom has original paint and you disturb it during remodel, you must hire an EPA-certified RRP contractor for dust containment and safe disposal; this is not the building department's role, but violation fines are $16,000+ per violation. Additionally, if you hire a contractor who is not RRP-certified and disturbs lead paint, the contractor is liable, but you (the homeowner) will face disclosure issues at sale. Cudahy does not waive RRP rules for owner-builder permits, so budget an extra $1,500–$3,000 for certified RRP work if you have a pre-1978 home.

Owner-builder permits are allowed for bathroom remodels in Cudahy under California B&P Code § 7044; however, you cannot self-perform plumbing or electrical work. You must hire a licensed plumber (California B&P license) for any work involving water lines, drains, or trap sizing, and a licensed electrician for any circuit installation, GFCI breaker, or exhaust fan wiring. You (the owner) can do demolition, framing, drywall, tile, and fixture installation (swapping in a pre-assembled toilet or faucet), but the licensed trades are non-negotiable. Owner-builder permit paperwork includes a statement that you are the owner doing the work, and you must sign a bond or statement of responsibility ($10,000 general liability recommended, though not always required for owner-builder residential work). If you misrepresent yourself as licensed (or hire an unlicensed plumber or electrician), Cudahy's code enforcement can issue a citation ($500–$2,000 per violation) and order removal of all non-compliant work.

Three Cudahy bathroom remodel (full) scenarios

Scenario A
Like-for-like fixture swap: new vanity, toilet, and faucet in existing Cudahy 1970s home, no plumbing relocation, no electrical work
You are replacing the toilet, sink, and faucet in the same location using existing rough-in plumbing. This is a surface-level cosmetic swap and does not require a Cudahy building permit, because the trap arms, vent stacks, and supply lines are not being moved or modified. You remove the old fixtures, cap or blank the existing rough-in if needed, and install new fixtures to the same connection points. Demolition and installation can be owner-performed; you do not need to hire a plumber. However, if your home was built before 1978 and the existing vanity cabinet or wall tiles contain lead paint, RRP compliance is still mandatory if you disturb the paint during removal — hire an EPA-certified RRP contractor for dust containment ($1,500–$3,000). After installation, test the fixtures for leaks and proper drainage. No inspection is required, but keep receipts for the new fixtures for your home records and future resale. Total cost: $2,000–$6,000 (materials and labor) with no permit fees. Timeline: 2–5 days.
No permit required | Like-for-like fixture swap allowed | Lead-paint RRP required if pre-1978 (add $1,500–$3,000) | Total $2,000–$6,000 | No permit fees
Scenario B
Full bathroom remodel with tub-to-shower conversion, relocated toilet and vanity, new exhaust fan in 2000s Cudahy home (no lead paint concerns)
You are gutting the bathroom: removing the existing tub and replacing it with a walk-in shower (requiring new waterproofing assembly), moving the toilet 4 feet to a new wall (new drain and trap arm), relocating the vanity sink 6 feet (new supply and drain lines), and installing a new exhaust fan with exterior duct termination. This is a full scope remodel requiring Cudahy building permits for plumbing, electrical, and potentially structural work. Start by submitting a permit application with floor plans showing the new fixture locations, a plumbing diagram showing trap-arm lengths (must be under 42 inches to the vent stack), the new shower waterproofing detail (e.g., cement board + redgard membrane or schluter kerdi with manufacturer spec sheet), the new exhaust fan CFM (minimum 50 CFM per IRC M1505.2, or 20 CFM if ducted to exterior per IEC 62301), and the new electrical circuit layout with GFCI protection shown. If the toilet is moved more than 4 feet, you likely need a secondary vent or a wet vent (dual-drain configuration), which increases complexity. Cudahy's Building Department will do a 2–3 week plan review, flag any missing waterproofing detail or trap-arm violation, and request resubmission if needed. Once approved, you can start work. Hire a licensed plumber for all plumbing rough-in, a licensed electrician for the exhaust fan circuit and any new outlets, and a licensed contractor or yourself for framing/drywall if walls are being moved. Rough plumbing inspection comes first (before walls close), then rough electrical, then drywall, then final. Rough plumbing will verify trap slope, vent placement, and trap-arm length; rough electrical will verify GFCI and exhaust fan wiring. Plan on 4–6 weeks from permit issuance to final inspection. Permit cost: $400–$700 (approximately 1.5% of the estimated $30,000–$40,000 project cost). Inspection fees: none additional (included in permit). Total project cost: $30,000–$60,000 depending on finishes and whether framing is required.
Permit required | Tub-to-shower waterproofing detail mandatory | Trap arm < 42 inches or secondary vent | Exhaust fan CFM and duct termination must be shown | Licensed plumber and electrician required | Rough plumbing, rough electrical, final inspections | Permit fee $400–$700 | Timeline 4–6 weeks
Scenario C
Bathroom remodel with wall relocation in 1950s Cudahy home, plumbing stays in place, owner-builder with licensed plumber hired, lead-paint compliance required
You are removing the wall between the bathroom and an adjacent bedroom to expand the bathroom footprint, then rebuilding a new partial wall 3 feet over to create a larger shower alcove. The plumbing fixtures (toilet, sink, tub drain) are staying in their original locations, so trap arms are not changing. However, the wall movement triggers structural review and waterproofing assembly review if the new wall backs a shower. Cudahy requires a structural engineer's letter or a simplified framing plan showing the new wall is load-bearing or not, and if it is load-bearing, you need a header calculation and an engineer's stamp. Submit the permit application with floor plans showing the old wall location (dashed) and new wall location (solid), a structural note or engineer's letter, plumbing rough-in diagram confirming no trap changes, electrical layout if any outlets are being added, and a note on whether the new wall will enclose or back a shower (if yes, waterproofing assembly required). Cudahy's plan reviewer will flag the structural work and likely request an engineer's letter (cost $300–$600 for a simple letter); without it, the permit will be on hold. Once you have the engineer's letter, resubmit and expect another 1–2 week review. Lead-paint RRP compliance is mandatory: any disturbance of walls, trim, or paint in a pre-1950s home requires EPA-certified RRP work. Budget $2,000–$4,000 for RRP dust containment and safe paint removal. You can be the owner-builder for demolition and framing, but you must hire a licensed plumber (even though the plumbing is not moving) if you want to show compliance on the permit — many Cudahy inspectors require a licensed plumber sign-off on the 'no change' statement. Rough framing inspection is critical here: the inspector will verify the new wall is properly framed and does not violate setbacks or structural codes. Allow 5–8 weeks total (permit plus plan resubmission, engineer, RRP work, framing inspection). Permit fee: $450–$800 (project valuation higher due to structural work). Engineer fee: $300–$600. RRP contractor: $2,000–$4,000. Total project cost: $25,000–$50,000 depending on finishes and whether you hire out framing.
Permit required | Structural engineer letter likely required ($300–$600) | Lead-paint RRP mandatory ($2,000–$4,000) | Licensed plumber sign-off recommended | Rough framing inspection required | Permit fee $450–$800 | Timeline 5–8 weeks

Every project is different.

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Cudahy's waterproofing mandate for shower and tub remodels

California's adoption of IRC R702.4.2 (waterproofing for wet areas) is enforced strictly by Cudahy inspectors, particularly for tub-to-shower conversions. The rule requires a water-resistant or moisture-proof membrane behind all tile in a shower surround (walls within 6 feet horizontally and 10 feet vertically of a shower door or spray head). Many homeowners and even some contractors assume cement board alone is sufficient; Cudahy's Building Department will reject this. You must specify a secondary membrane: redgard, kerdi, hydroban, or equivalent, with manufacturer's application documentation. This adds $500–$1,200 to labor and materials.

If you are installing a pre-fabricated shower pan or acrylic tub surround (one-piece unit), waterproofing is built-in and you do not need a secondary membrane behind the surround itself; however, any wall area outside the surround (e.g., an accent wall or a knee wall) still requires waterproofing if it is within the wet zone. Cudahy's inspectors will verify this during rough framing or drywall inspection, so call for an inspection before you tile. The city does not require a moisture test (calcium chloride test) as a condition of final approval, but if you are refinancing or selling, your lender may require one.

For tub remodels where you are keeping a tub in place (not converting to shower), waterproofing behind the tub surround is still required if you remove and re-tile the existing surround. If you are simply re-caulking an existing tub surround and not disturbing the drywall or tile, no permit is needed and no new waterproofing is required — you are doing cosmetic maintenance only.

Exhaust fan sizing, ducting, and GFCI/AFCI requirements in Cudahy bathrooms

Cudahy enforces California's adoption of IRC M1505 (exhaust fan ventilation), which requires a minimum CFM (cubic feet per minute) based on bathroom size: 50 CFM for bathrooms under 100 square feet, or 1 CFM per square foot for larger bathrooms. A standard 5x8 bathroom (40 sq ft) needs at least 50 CFM; a 10x12 master bathroom (120 sq ft) needs at least 120 CFM. The fan must be ducted to the exterior (roof, wall, or soffit), not into the attic — Cudahy's inspectors will flag any ductwork that terminates in unconditioned space. Flexible duct (foil or vinyl) can be used, but the run should be as straight as possible (no sharp bends that restrict airflow), and the exterior termination must include a damper. Most homes use a soffit or gable termination; roof termination is allowed but requires flashing.

Electrical code for the bathroom (NEC 210.8(A), adopted in California) requires GFCI (Ground Fault Circuit Interrupter) protection for all outlets within 6 feet of a sink or tub, and AFCI (Arc Fault Circuit Interrupter) protection for all branch circuits supplying outlets in the bathroom. You can meet this with a GFCI receptacle (cheaper, ~$15–$30 per outlet) or a GFCI breaker in the main panel (protects the entire circuit, ~$40–$100 per breaker). Cudahy's inspectors will check that GFCI outlets or breakers are properly labeled and operational during rough electrical and final inspection. If you add a new exhaust fan circuit, that circuit must also have AFCI protection (often combined in a single breaker, ~$60–$120).

Ducting material and installation are inspected during rough framing or rough electrical depending on when the ductwork is run. Use UL-approved ductwork (rigid or flex), avoid dryer-vent-style foil (not rated for bathroom exhaust), and ensure the duct has no kinks or crushing that would reduce airflow. Cudahy does not require a ductwork CFM test, but the inspector will visually verify that the duct is continuous from the fan to the exterior termination and is not crushed or disconnected. Many inspectors will ask you to remove insulation temporarily to see the duct run.

City of Cudahy Building Department
Cudahy City Hall, 4819 Santa Fe Avenue, Cudahy, CA 90201
Phone: (323) 562-7551 (verify with city website for current permit-line phone) | https://www.cudahy.ca.us (building permit portal or submission instructions linked from homepage)
Monday–Friday, 8:00 AM–5:00 PM, closed city holidays

Common questions

Do I need a permit if I'm only replacing tiles and grouting in my bathroom?

No, tile replacement or grouting in an existing installation is cosmetic maintenance and does not require a permit. However, if you remove the existing tile and are re-tiling the shower surround (walls within the wet zone), the underlying waterproofing assembly must be inspected, and you may need a permit if structural changes or new waterproofing is required. If in doubt, call the Cudahy Building Department at (323) 562-7551 and describe the scope.

Can I do a bathroom remodel as an owner-builder in Cudahy?

Yes, Cudahy allows owner-builder permits under California B&P Code § 7044. However, you cannot self-perform plumbing work (drain, supply line, or trap sizing changes) or electrical work (new circuits, GFCI breaker installation). You must hire a licensed California plumber and electrician for those tasks. You can do demolition, framing, drywall, tile, and fixture installation yourself. Owner-builder permit requires you to sign a statement of responsibility and is typically issued without a bond for residential work under $150,000.

How long does it take to get a bathroom remodel permit approved in Cudahy?

Cudahy's standard plan-review timeline is 2–5 weeks depending on plan completeness. If the plans are missing waterproofing detail, GFCI/AFCI layout, or plumbing trap arm sizing, the city will issue a request for changes (RFC) and you will resubmit. Resubmission typically takes another 1–2 weeks. If structural work is involved (wall relocation), add 1–2 weeks for engineer review. Total: 2–8 weeks from initial submission to permit issuance.

What is the most common reason Cudahy rejects a bathroom remodel permit application?

Missing shower waterproofing assembly detail. Many contractors submit plans that show 'cement board and tile' without specifying the waterproofing membrane (redgard, kerdi, hydroban, etc.) or including manufacturer's installation documentation. Cudahy requires the specific product and installation steps. A close second is missing trap-arm length notation on the plumbing plan; if the trap run is over 42 inches and no secondary vent is shown, the city will reject it.

Do I need a permit to add a new exhaust fan to my bathroom?

Yes, if the exhaust fan is new (not replacing an existing fan in the same location with the same ductwork). New fans require electrical roughing (wiring and AFCI protection) and ductwork routing, both of which must be inspected and shown on the permit plan. You cannot just install an exhaust fan without a permit in Cudahy. If you are replacing an existing fan in place with the same duct, Cudahy may waive the permit requirement, but you should confirm with the Building Department first.

Are there lead-paint requirements for my 1965 Cudahy bathroom remodel?

Yes. Any home built before 1978 is presumed to contain lead paint. If your remodel involves disturbing walls, cabinets, trim, or paint (including demolition), an EPA-certified RRP (Renovation, Repair, Painting) contractor must perform or oversee the work with proper dust containment and safe disposal. You cannot hire an unlicensed contractor or do this work yourself without RRP certification. Violations carry fines up to $16,000 per offense. Budget $2,000–$4,000 for RRP compliance.

Can I move my toilet and sink in Cudahy without a plumber?

No. Any relocation of plumbing fixtures (toilet, sink, shower valve) requires a licensed California plumber. The plumber must verify trap-arm lengths (under 42 inches), slope (1/4 inch per foot), and vent placement, all of which are inspected by Cudahy's Building Department. You can demo the existing fixtures and finishes, and install new fixtures once the rough-in is approved, but the rough-in work itself must be licensed.

What does a bathroom remodel permit cost in Cudahy?

Cudahy charges approximately 1–2% of the estimated project valuation. A $20,000 remodel costs $300–$400 in permit fees; a $40,000 remodel, $400–$800. There are no separate plan-review fees upfront, but if plans are rejected and resubmitted, a $75–$150 resubmission fee applies. No inspection fees are charged separately. If you need a structural engineer's letter (for wall relocation), that is an additional $300–$600 paid to the engineer, not Cudahy.

Do I need a GFCI outlet or a GFCI breaker for my new bathroom circuit?

Either is acceptable to Cudahy's code enforcement, but they differ in scope and cost. A GFCI receptacle (~$20–$30) protects only that outlet and any downstream outlets on the same circuit. A GFCI breaker (~$60–$100) protects the entire circuit. A GFCI breaker is more convenient if the bathroom circuit is new; a GFCI receptacle is cheaper if you are upgrading an existing circuit. Cudahy's inspector will verify that at least one method is in place and functional during final inspection.

If I skip the permit for a bathroom remodel and the city finds out, what happens?

The city will issue a stop-work order and you will face fines of $300–$1,000 per day of violation. When you finally permit the work, you will pay double permit fees (typically $600–$1,200 total). If the unpermitted work is discovered during a home inspection for a sale or refinance, your lender or title company will block the transaction until the work is inspected and brought to code (often costing $3,000–$8,000 in remedial work). Insurance may also deny a water-damage claim if the cause is traced to unpermitted plumbing 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 Cudahy Building Department before starting your project.