Bathroom Remodel Permit in Danville, CA (2026)

Research by DoINeedAPermit Research Team · Updated May 2026

The Short Answer

A full bathroom remodel in Danville requires a building permit if you're relocating plumbing fixtures, adding electrical circuits, installing new exhaust ventilation, converting tub to shower, or moving walls. Surface-only work—tile, vanity, faucet swap in place—is exempt.

Danville Building Department enforces the California Building Code (Title 24) and uses a hybrid workflow: most bathroom permits under $5,000 valuation can be filed online via the city's e-permit portal and approved over the counter without full plan review, BUT projects involving fixture relocation, new electrical circuits, or structural changes (wall removal) trigger mandatory plan review and a 2–5 week approval cycle. This is notably faster than many Bay Area neighbors (Walnut Creek, Pleasanton) that route all bathroom permits through full plan-review queues. Danville's cost is also lower — permit fees run $200–$800 depending on project valuation, roughly 1–2% of estimated construction cost. The city adopts 2022 Title 24 standards, which include stricter GFCI/AFCI rules for bathroom circuits and require pressure-balanced shower valves. Pre-1978 homes trigger lead-paint disclosure (California Residential Lead-Based Paint Hazard Disclosure) but do not stop work. Trade licensing is mandatory in California — you cannot DIY plumbing or electrical; a licensed contractor or trade-licensed owner-builder must pull the permit and do the work.

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

City inspectors or neighbors report unpermitted work: stop-work order issued, plus fines of $250–$500 per violation day (can compound to $5,000+) and forced removal of non-code work.
Home insurance claim denied: if bathroom flood or electrical fire occurs during or after unpermitted work, homeowner's insurance will refuse payout and may cancel coverage.
Title transfer blocked: when you sell, the TDS (Transfer Disclosure Statement) requires honest disclosure of unpermitted work; buyer can demand removal or price reduction of $10,000–$50,000+.
Refinance or HELOC denied: lenders require title insurance, which typically fails if unpermitted major systems (electrical, plumbing) are discovered during appraisal.

Danville bathroom remodel permits — the key details

Danville's permit threshold is straightforward: if you're touching plumbing, electrical, or structure, you need a permit. The California Building Code (Title 24, Sections 422–428) governs bathroom construction statewide, but Danville's online portal and over-the-counter approval for smaller jobs makes the process faster than manual submission. The core rule is simple—any relocation of a toilet, sink, shower, or tub requires a plumbing permit, even if you're staying within the same wall cavity. New exhaust fans triggering ductwork changes also require permits. If you're swapping a faucet in place, replacing the toilet with an identical model, or re-tiling the shower walls without structural change, you're exempt. The distinction matters because many homeowners think 'remodel' automatically means permit, when in fact a cosmetic refresh (new vanity cabinet, mirror, lighting in existing locations) can be done unpermitted if electrical is not added. That said, if you're adding a GFCI outlet, new lighting circuit, or 240V heat lamp, the moment electrical work is introduced, the entire bathroom falls under permit jurisdiction. Danville Building Department staff will confirm scope over the phone or via the online portal's intake form—call ahead to clarify borderline projects.

The waterproofing requirement is the most common rejection point in Danville bathroom remodels, especially for tub-to-shower conversions. IRC R702.4.2 mandates a waterproofing membrane (cement board + liquid membrane, or pre-formed waterproofing pan system) behind all shower walls and under the shower floor. Applicants frequently omit this detail from their plan or specify 'just drywall and tile,' which will fail inspection. Danville's inspector will request a detailed waterproofing schedule (material name, installation sequence, manufacturer's installation guide) before framing inspection; you cannot proceed to drywall without approval. This delays jobs 1–2 weeks if caught at plan review. The best practice is to include manufacturer spec sheets (e.g., Hydro Ban, Schluter, or comparable) with your initial permit application. Pre-formed shower pan systems (one-piece ABS or acrylic) are easier to document and often approved faster than membrane systems because the waterproofing assembly is factory-certified.

Electrical compliance is the second common friction point. The 2022 Title 24 code requires all bathroom outlets and lighting on dedicated circuits with GFCI or AFCI protection. Specifically, NEC 210.12(B) mandates GFCI for all receptacles within 6 feet of the sink, and AFCI protection for all branch circuits supplying outlets in the bathroom. Many older Danville homes (built 1980s–2000s) have shared bathroom–hallway circuits, which must be converted to dedicated circuits during a full remodel. This often requires a sub-panel upgrade or breaker adjustment, adding $500–$1,500 to the electrical cost. Danville's plan review requires a one-line electrical diagram showing panel layout, circuit assignments, and GFCI/AFCI details; vague electrical scopes will be rejected. A licensed electrician should prepare this diagram (included in the permit fee). If you're doing a modest remodel (vanity swap, new fixture in place) without adding circuits, you still need an electrician to verify GFCI compliance on existing outlets—code-compliant bathrooms built before 2022 may lack AFCI on the lighting circuit, which can now be cited as a deficiency.

Plumbing trap-arm and vent rules are often overlooked. IRC P2706 limits trap-arm length (the horizontal pipe from trap to vent) to 4 feet for a 1.5-inch drain (typical for sinks) and 6 feet for a 2-inch drain (toilets); exceeding this causes backflow and sewage smell. When relocating a sink or toilet, the new drain run must be reviewed for trap-arm compliance. Danville homes with crawlspaces or attics make this easier (vertical vent routing is possible), but second-story bathrooms often face tight routing; applicants sometimes propose oversized trap arms, which fail inspection. Request a plumbing plan showing trap location, vent routing, and measurements. Ventilation (exhaust fan ductwork) must also be sized and routed to the exterior; undersized ducts or termination in an attic (a very common illegal shortcut) will be caught during rough inspection.

The permit process in Danville follows these steps: (1) File online via the city's e-permit portal or in person at City Hall; (2) Provide scope, valuation, and preliminary plans (sketch acceptable for over-the-counter jobs); (3) Pay permit fee ($200–$800 depending on valuation; typically 1–2% of estimated construction cost); (4) Receive plan-review comments within 5–10 business days if structural/electrical/plumbing changes trigger full review, or same-day approval if over the counter; (5) Correct and resubmit if needed (add 1–2 weeks); (6) Once approved, schedule rough plumbing, rough electrical, framing, and final inspections. Total timeline: 2–5 weeks from filing to approved-to-build. Inspections are scheduled online or by phone; inspectors typically show up within 1–2 business days of request. Final inspection (sign-off on all systems) can take another 1–2 weeks. The city does NOT require a separate mechanical permit for the exhaust fan if it's a standard ducted unit; it's bundled under the plumbing permit.

Three Danville bathroom remodel (full) scenarios

Scenario A

Cosmetic bathroom refresh, Danville Hills bungalow—new vanity, tile, mirror, same plumbing locations

You're removing the old 30-inch vanity and replacing it with a new 36-inch model, re-tiling the shower surround, adding a new mirror and lighting fixture, and swapping the toilet in place (same location, same rough-in height). No walls are moving, plumbing rough-ins stay identical, and you're adding one new lighting outlet on an existing circuit with a simple GFCI outlet. Because you're not relocating fixtures, adding new circuits, or changing structure, and the new lighting is only a single outlet (not a new dedicated circuit), this project is EXEMPT from permitting under California Building Code. However, California law requires that any electrical work be performed by a licensed electrician or a licensed electrical contractor; you cannot do it yourself. The electrician will install a 15-amp breaker and run 14/2 NM cable to the new fixture with GFCI protection. Tile work (removing old, applying new mortar, grouting) does not require a permit—it's finish work. Total cost: $3,000–$6,000 (vanity $400–$800, tile $1,500–$2,500, electrical labor $400–$600, plumbing labor for fixture swap $300–$500). Timeline: 1–2 weeks, no permit fees. No inspections required. If you later decide to add a heated towel rack on a new 240V circuit, that triggers a permit retroactively—file before closing the walls.

Scenario B

Full bathroom gut with fixture relocation, new exhaust fan duct, Danville downtown Victorian, tub to shower conversion

You're removing the existing 5-foot cast-iron tub and replacing it with a 3-foot shower stall. The tub drain (2-inch waste line) runs under the floor to a stack 12 feet away; the new shower drain (2-inch) will be relocated 4 feet to the side, running horizontally 6 feet to the same stack. You're also removing an old inline exhaust fan (no ductwork, venting into the attic) and installing a new 110 CFM fan with insulated ducted vent through the roof. The bathroom lighting is on a shared hallway circuit; you're adding a heat lamp requiring a dedicated 240V circuit. All walls stay in place. This project REQUIRES a permit under California Title 24 due to the fixture relocation (tub-to-shower conversion with new drain run), new exhaust vent ductwork (IRC M1505), and new dedicated electrical circuit (240V heat lamp). Danville Building Department will require: (1) a plumbing plan showing trap-arm length (must be ≤4 feet from 2-inch drain to vent) and vent routing; (2) a waterproofing detail for the new shower (cement board + liquid membrane or pre-formed pan, with manufacturer spec sheet); (3) a one-line electrical diagram showing the new 240V circuit with breaker assignment and any AFCI upgrades; (4) an exhaust-fan spec showing CFM rating, duct diameter (typically 4 inches), and roof-termination detail. Plan-review process: Submit online or in person; permit fee $400–$700 (typically 1.5–2% of $25,000–$40,000 estimated construction cost). Plan review: 5–10 business days (may require one resubmission for waterproofing or duct routing detail). Once approved, schedule inspections: rough plumbing (drain location, trap-arm length, vent routing), rough electrical (240V circuit, AFCI breaker), and framing (if any drywall removal/patching). Drywall inspection is optional if no structural work. Final inspection after tile, fixture installation, and ductwork sealing. Total timeline: 3–5 weeks from filing to final sign-off. The biggest risk: new drain run trap-arm exceeds 4 feet, requiring a secondary vent (cheater vent) addition, which adds cost and delays framing. Request a plumbing sketch from the contractor before filing to confirm trap-arm distance.

Scenario C

Secondary bathroom renovation, Danville hillside home, structural wall removal to enlarge space, new toilet and vanity locations

You're enlarging the 5x7-foot bathroom by removing a non-load-bearing wall between the bathroom and adjacent guest bedroom, creating an 8x7-foot space. The toilet is being moved from one corner to a new location 6 feet away on the opposite wall; the sink/vanity moves 8 feet. The shower stall (existing, no tub conversion) stays in place but the new toilet drain will cross beneath the existing vanity drain—both must vent to the existing 3-inch stack 15 feet away. You're adding a new GFCI outlet at the relocated vanity location and upgrading the lighting to two new fixtures on a dedicated AFCI circuit (200W total). This project REQUIRES a permit under multiple California Title 24 triggers: (1) structural wall removal (even non-load-bearing walls require a building permit and may require engineer certification if the wall has any mechanical systems or lateral-bracing function); (2) fixture relocation requiring new plumbing runs; (3) new dedicated electrical circuit. Danville's permit scope is broadest here because structural work is involved. You'll need: (1) a structural engineer's letter confirming the wall is non-load-bearing and can be removed (cost $300–$500); (2) a framing plan showing wall removal, header details (if any opening created), and drywall patches; (3) a plumbing plan with both drain runs, trap-arm lengths, and vent routing (two separate drain lines converging on the stack requires careful venting design per IRC P2706); (4) an electrical one-line diagram showing the new dedicated circuit with AFCI breaker, outlet locations, and any panel upgrades; (5) a waterproofing detail if the shower finish is being redone (if shower is untouched, waterproofing detail is waived). Permit fee: $600–$950 (approximately 1.5–2% of $40,000–$50,000 estimated construction cost). Plan review is mandatory and will take 7–14 business days due to structural and plumbing complexity; expect one round of resubmissions (1–2 weeks). Once approved, inspections sequence: framing inspection (wall removal, header installation, drywall patch framing), rough plumbing (trap-arm length, vent routing, convergence of two drains on stack), rough electrical (dedicated AFCI circuit, outlet boxes), drywall inspection, final. Total timeline: 4–6 weeks from filing to final sign-off. The biggest risk: two drain lines tying into one stack too close together can violate trap-arm spacing rules (IRC P3005 requires minimum distances); a plumber and engineer coordination is essential before filing. Also, if the wall contains any plumbing, electrical, or HVAC runs, removal becomes more complex and may delay approval 1–2 weeks.

Permit required | Structural wall removal (non-load-bearing) requires engineer letter | Fixture relocation, new dual drain runs | Two drains converging on stack (spacing compliance critical) | New dedicated AFCI circuit required | Structural plan, plumbing plan, electrical plan required | Permit fee $600–$950 | Typical cost $40,000–$65,000 | Plan review 7–14 days, one resubmission likely, total 4–6 weeks

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Waterproofing assemblies and shower conversion details for Danville bathrooms

Exhaust ventilation is regulated by IRC M1505 and Title 24 Section 422; Danville enforces both. The core requirement is simple: bathroom exhaust fans must be ducted to the exterior (not into attic or walls) with a minimum 110 CFM capacity for a typical 5x8-foot bathroom (larger bathrooms or spa-like upgrades may require 150–200 CFM). The duct must be 4-inch diameter minimum, insulated (to prevent condensation), and routed to a roof or wall termination with a damper that closes when the fan is off. Danville's plan review will request: (1) exhaust-fan specification (CFM rating, model number, noise rating in sones); (2) duct routing diagram (show path from bathroom to exterior); (3) termination detail (roof vent vs. wall cap); (4) switch location (must be accessible and typically on a dedicated circuit if the fan has lights or heating). A very common violation is venting into the attic (illegal in California and a fire/moisture hazard); Danville inspectors will catch this during rough inspection and issue a correction notice. If your home has a cathedral ceiling or limited attic space, routing ductwork can be tricky—the duct cannot be longer than 25 feet (per Title 24), and each 90-degree elbow reduces effective CFM by ~10%, so routing efficiency matters. Condensation in long or uninsulated ducts is another issue: insulated ducts cost $200–$400 more but prevent dripping and mold inside the ductwork. Danville's coastal climate (high humidity in fall/winter) makes insulated ducts a best practice, even though the code technically allows uninsulated in some climates. If the existing fan outlet is to be relocated (e.g., moving from an old side-wall termination to a new roof termination), the plan must show both the removal of the old duct and the new routing.

Electrical GFCI/AFCI compliance and circuit requirements for Danville bathrooms

GFCI outlets and AFCI breakers are distinct and both required in a compliant modern bathroom. GFCI (ground-fault circuit interrupter) protects against electrocution due to moisture; it detects a current imbalance between the hot and neutral wires (which would occur if you touched a live wire while wet) and cuts power in milliseconds. An AFCI (arc-fault circuit interrupter) protects against fire caused by arc faults (electrical sparks in damaged wire insulation). A GFCI outlet has a test/reset button on the face; an AFCI breaker is in the panel and protects the entire circuit. Danville's plan review will verify that both are specified. A common DIY mistake is installing a basic 15-amp outlet and assuming the existing breaker will protect against ground faults—it won't. The outlet itself must be GFCI-rated. Alternatively, the breaker can be a GFCI breaker, which protects all outlets on that circuit (no GFCI outlets needed), but GFCI breakers cost $50–$100 more than regular breakers, and some electricians prefer GFCI outlets at each sink location for simplicity. For a bathroom remodel, the safest approach is to have a licensed electrician design the circuit layout and specify GFCI/AFCI details; this is part of the permit application cost ($150–$300 for the electrician's plan and site visit). If a heat lamp or ventilation fan has a 240V requirement, a separate dedicated circuit is needed—this is not shared with 120V lighting or outlets. Danville's inspector will verify breaker sizing, wire gauge, and grounding at rough-in inspection, so accurate electrical planning prevents costly rework.

City of Danville Building Department
510 La Gonda Way, Danville, CA 94526
Phone: (925) 314-3300 | https://danville.ca.gov/departments/planning-building
Monday–Friday, 8:00 AM–5:00 PM (closed holidays; call to confirm permit counter hours)

Common questions

Can I pull my own bathroom permit in Danville if I own my home?

No. California Building Code and Danville's local code require that all plumbing and electrical work be performed by licensed contractors or licensed owner-builders. An owner-builder license (Business & Professions Code § 7044) is available only if you intend to build your own residence, and it still requires a licensed plumber and electrician to perform the trade work on a bathroom remodel. You can pull the permit as the owner (homeowner), but you cannot do the plumbing or electrical work yourself. Hire a licensed general contractor or trade-specific contractors (plumber + electrician) to perform the work and manage the permit.

What happens during the plan-review phase, and how long does it take in Danville?

Plan review is the city's inspection of your submitted plans (plumbing, electrical, framing, waterproofing) against code before you start work. Danville's plan review for bathroom remodels typically takes 5–14 business days depending on project complexity. Over-the-counter approvals (small cosmetic scopes) happen same-day. If your plans are incomplete or non-compliant (e.g., waterproofing detail missing, GFCI not shown, trap-arm too long), the reviewer issues comments in writing; you correct and resubmit, which adds 1–2 weeks. Once approved, you receive a building permit card and can begin work. Inspections are then scheduled as work progresses (rough plumbing, rough electrical, framing, final).

Do I need a structural engineer for a bathroom remodel in Danville?

Only if you're removing or modifying a wall, reroofing to add an exhaust duct, or making changes to the building's structural system. A simple fixture relocation (toilet, sink, shower in new location) does not require an engineer if no walls are involved. If you're removing even a non-load-bearing wall, Danville Building Department recommends (sometimes requires) an engineer's letter confirming it can be safely removed. Cost: $300–$500 for a letter; $1,500–$3,000 for a full structural plan. Ask the city at permit intake whether your specific wall removal needs engineering.

What's the cost of a bathroom remodel permit in Danville, and is that in addition to contractor costs?

The permit fee ranges from $200–$800 depending on estimated project valuation (typically 1–2% of construction cost). A $30,000 bathroom remodel pays roughly $450–$600 in permit fees. This is separate from contractor labor and materials. The permit fee pays for plan review, inspections, and administrative processing; it does not include design, engineering, or construction. Some contractors roll the permit cost into their bid; others charge it separately.

Can an existing GFCI outlet on the vanity serve the new heat lamp on a 240V circuit?

No. A 240V heat lamp requires a dedicated 240V circuit with its own breaker and wire run; it cannot share a 120V outlet or circuit. GFCI outlets are rated 120V only. The heat lamp circuit must be installed separately by a licensed electrician. If you're adding a 120V heated towel rack, it can use a GFCI outlet on the main bathroom circuit, but again, the outlet must be GFCI-protected by breaker or outlet device.

What is the lead-paint disclosure requirement for pre-1978 bathrooms in Danville?

California law requires sellers of homes built before 1978 to disclose lead-paint hazards. If you're doing a bathroom remodel in a pre-1978 Danville home, you are legally required to provide the EPA pamphlet 'Protect Your Family from Lead in Your Home' and allow a 10-day lead inspection period (unless waived by the buyer). Work can proceed regardless, but disclosure is mandatory. If renovation disturbs lead paint, EPA RRP (Renovation, Repair, and Painting) rules apply: the contractor must be EPA-certified and use containment/cleanup protocols. Cost: typically included in contractor estimate or $500–$2,000 added to project. Danville Building Department does not enforce lead rules directly; California Department of Toxic Substances Control does.

If I'm only replacing the faucet and vanity in the same location, is a permit needed?

No. Swapping a faucet (in the same sink location) and replacing a vanity cabinet (in the same footprint) without moving plumbing rough-ins or adding electrical circuits is exempt from permitting under California Building Code. This is finish work. However, if you're adding a new outlet (GFCI) or light fixture, a permit is triggered. Also, if the vanity replacement reveals code non-compliance in the existing plumbing (e.g., no trap, corroded trap), the city may require correction before sign-off—though typically this is not caught unless you pull a permit for associated work.

How long does a full bathroom remodel typically take from permit filing to final inspection in Danville?

For a moderate-scope remodel (fixture relocation, new exhaust duct, electrical upgrade): 3–5 weeks from filing to final approval. For a simple cosmetic project (no permit required), 1–2 weeks of construction. For a complex remodel involving structural wall removal: 4–6 weeks or longer. The timeline is split between plan review (5–14 business days), construction (1–3 weeks), and inspections/final approval (3–7 days after requested). Delays occur if plan review comments require resubmission or if inspections find non-code-compliant work.

What if my bathroom exhaust fan vents into the attic? Do I need to fix it during a remodel?

Yes. Venting an exhaust fan into the attic violates California Building Code (IRC M1505) and creates moisture and mold hazards. If you're pulling a permit for a bathroom remodel, Danville's inspector will require that the existing fan ductwork be extended to the exterior (roof or wall termination). This is a code violation, not an optional upgrade. If you're only doing cosmetic work (no permit), you can leave the old fan in place, but if the fan fails and you replace it, extending the duct to the exterior is required at that time. Cost to reroute: $400–$800 depending on attic accessibility and roof/wall location.

Is a pressure-balanced shower valve required by Danville code?

Yes. California Title 24 and IPC (International Plumbing Code) require pressure-balanced or thermostatic mixing valves in all new or remodeled showers and tubs to prevent sudden temperature changes caused by pressure drops in the supply line (anti-scald). Danville's plan review will verify that the valve specification on your permit application includes 'pressure-balanced' language. A standard 3-handle or single-handle valve without pressure-balancing will be rejected. Cost: pressure-balanced valves run $150–$400 (vs. $30–$80 for basic valves). Installers know this requirement, so it's usually included automatically, but verify in the permit documents.

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 Danville Building Department before starting your project.

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