Bathroom Remodel Permit in Portsmouth, NH (2026)

Research by DoINeedAPermit Research Team · Updated May 2026

The Short Answer

A full bathroom remodel in Portsmouth requires a permit if you are moving fixtures, adding electrical circuits, installing new exhaust ventilation, converting a tub to shower, or relocating walls. Surface-only work—tile, vanity swap in place, faucet replacement—does not need a permit.

Portsmouth Building Department enforces New Hampshire Building Code (adopted from the 2020 IBC/IRC), which treats bathroom remodels as interior work triggering permits whenever any plumbing fixture relocates, electrical service changes, or drainage/ventilation systems are altered. What sets Portsmouth apart from other Seacoast towns is its dual enforcement layer: the city also applies its own local amendments around historic-district overlay compliance and stormwater runoff (relevant when exhaust fans route condensation), plus it requires Plan Review Board sign-off on certain scope changes. Unlike some Granite State municipalities that allow over-the-counter permitting for minor bath work, Portsmouth routes full remodels through formal plan review, typically 10-15 business days. The city's online permit portal (accessible through the Portsmouth city website) allows digital submission but does not auto-approve bathroom projects—a reviewer will flag missing waterproofing details, GFCI/AFCI circuit specifications, and exhaust-duct termination drawings before issuing. Frost depth in Portsmouth is 48 inches, but that applies mainly to below-grade plumbing in basements; for second-floor and first-floor bath remodels, the bigger local constraint is the city's requirement that all new drains (if moving fixture drains) must satisfy trap-arm length limits under IRC P3005.2 (typically 5 feet from trap to vent, depending on pipe diameter). Lead-paint rules (federal RRP, not city-specific) apply to any pre-1978 home—disclosure and containment are required before demolition.

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

Stop-work order + $500 fine in Portsmouth; contractor loses license if they pulled work unpermitted on your behalf.
Insurance claim denial: your homeowner's policy excludes unpermitted work, leaving you liable for injury or water damage ($10,000–$50,000+ in bathroom mold/structural remediation).
Resale disclosure hit: the Residential Property Disclosure Statement (New Hampshire RPADC form) requires listing unpermitted renovations; buyers can sue within 2 years of closing ($5,000–$20,000 settlement cost).
Lender/refinance block: most lenders pull permit history; unpermitted remodels trigger appraisal holdups and mortgage denials.

Portsmouth full bathroom remodel permits — the key details

The core trigger in Portsmouth is IRC R101.2 (Work Requiring Permits): any change to plumbing fixtures, electrical systems, ventilation, or structural elements requires a permit application. For bathrooms, this means moving a toilet, sink, or tub to a new location automatically requires permitting—even if you're only shifting 3 feet. Adding a new exhaust fan or replacing an existing one with larger ductwork also triggers a permit because IRC M1505.1 mandates that all exhaust fans must be ducted to the exterior (not to an attic or soffit) and sized per fixture load, typically 50 CFM (cubic feet per minute) minimum for a full bathroom. Converting a tub to a shower (or vice versa) requires a permit because the waterproofing assembly changes: the code mandates a continuous, impermeable membrane underneath the tile or finish (IRC R702.4.2 specifies cement board + membrane for shower surrounds, sloped pan or liner for tub areas). If you're relocating a drain line, Portsmouth inspectors will check that your trap arm doesn't exceed the maximum length (per IRC P3005.2: for a 1.5-inch trap, max 5 feet from trap to vent; for 2-inch, max 10 feet)—violation of this is one of the top reasons for rough-plumbing rejections in the city. Any new electrical circuits added for heated towel rails, GFCI outlets, or exhaust fans must be drawn on a one-line electrical diagram and comply with NEC 210.8 (GFCI protection for all bathroom receptacles) and NEC 210.12 (Arc-Fault Circuit Interrupters for all bedroom and bathroom branch circuits in NH)—Portsmouth inspectors routinely reject plans that don't show AFCI devices on the main panel diagram. The city does NOT require a separate mechanical permit for exhaust fans in bathrooms (they fall under the electrical/plumbing permit bundle), but the duct routing to the exterior must be clearly marked and cannot route to an unconditioned attic.

Portsmouth's local code environment adds practical wrinkles that differ from towns 20 minutes away like Durham or Newmarket. First, Portsmouth's Building Department has one of the tighter plan-review timelines on the Seacoast—submissions are screened within 3–5 business days, but resubmissions often take another 7–10 days if corrections are needed (missing waterproofing specs, GFCI details, or exhaust-duct termination drawings are the three most common rejection items). The city's online permit portal (Portsmouth.nh.gov/building) allows PDF upload of permit forms and plans, but the portal does not provide real-time status updates; you must call or email the Building Department to check review progress. Second, Portsmouth is split between a historic district (downtown/waterfront) and non-historic zones; if your bathroom is in a listed historic home or in the historic district overlay, the Planning Board may require a Certificate of Appropriateness (COA) before renovation begins—this adds 2–4 weeks and is NOT included in the basic permit fee. Third, any work in bathrooms within 5 feet of the exterior wall must account for Portsmouth's stormwater management rules (City of Portsmouth Stormwater Ordinance): exhaust-fan condensate cannot be routed to the ground surface in a way that contributes to erosion or flooding. Most modern exhaust ducts handle this automatically, but inspectors will ask where the condensation will drain if ductwork runs 40+ feet. Fourth, if your home was built before 1978, the federal RRP (Renovation, Repair, Painting) rule applies: any disturbing of paint (removal, sanding) requires an EPA-certified contractor or homeowner notification and containment (this is not a city rule, but Portsmouth inspectors will note it in the permit file if they suspect lead paint).

Exemptions in Portsmouth are narrow but real. Per IRC R101.2 and NH Building Code adoption, interior finish work—including tile, paint, fixture replacement in the existing location, faucet swaps, towel-bar installation, and vanity cabinet replacement—does NOT require a permit as long as no plumbing, electrical, or drainage is disturbed. For example, if you're removing the old tile and re-tiling the same shower surround with the same plumbing rough-in, no permit is needed; if you're moving the shower head or relocating the drain, a permit is required. Likewise, a simple toilet replacement (removing the old bowl and wax ring, installing a new one in the same flange location) is exempt; but a toilet relocation (moving the flange to a new spot on the floor) requires a permit because the drain line and vent may need adjustment. The city's Building Department FAQ (available on the city website) explicitly states: 'Cosmetic updates to existing bathrooms without moving fixtures or changing electrical load are exempt.' This distinction is critical for budgeting: if you're doing a full-gut remodel with new tile, fixtures, lighting, and ventilation, you'll need a permit (~$300–$600 fee); if you're doing a vanity/faucet/tile refresh in place, you don't need a permit (zero fee, no inspections). The exemption does NOT apply to new bathrooms added to a house (e.g., converting a bedroom closet to a powder room)—that's a new fixture scenario and requires full mechanical, electrical, and plumbing permitting.

Portsmouth's climate and soil context matter for long-term compliance. Zone 6A means cold winters (average low -15°F, frost depth 48 inches), so any new drain lines or new plumbing rough-in must slope properly and be protected from freezing if they run near exterior walls or through unheated spaces. If you're relocating a toilet to a new location near an exterior wall, the vent stack must exit the roof above the snow-load line (per NH amendments to IRC), and the trap must be insulated or heated if it's in a cold space—inspectors will ask about this during rough-plumbing inspection. Glacial soil (granite bedrock is common in Portsmouth) means minimal settling issues, so foundation/basement bath relocations are generally straightforward. However, if you're adding a new drain line that crosses existing granite ledge or bedrock, you may need a licensed excavator and may trigger soil/foundation review, adding 5–10 days to the permit timeline. Exhaust-fan duct routing in cold climates must have a damper (to prevent cold-air backdrafting) and, in Portsmouth's case, should terminate on the roof above the eave line or on a side wall at least 2 feet above ground—the city enforces this strictly because improper termination leads to ice dams and attic moisture (a common complaint during inspections).

What comes next after you apply: Portsmouth Building Department will issue a permit number and send you a one-page approval (email, if submitted online) within 5–10 business days if the submission is complete. The permit fee is typically $300–$600 depending on valuation (the city uses a 0.75–1.2% fee schedule based on project cost; a $30,000 full-bath remodel pays ~$300–$360 in permit fees, plus $75 inspection fees per rough-plumbing and rough-electrical inspection, plus a $75 final inspection). Once issued, the permit is valid for 6 months (extendable); you must display it on-site during work. Inspections are scheduled by the homeowner or contractor: Rough Plumbing (after drain/supply lines are installed but before walls are closed), Rough Electrical (after circuits are run and AFCI/GFCI devices are in place but before outlets are trimmed out), Framing/Drywall (usually required if walls are moved or new studs installed, often skipped if only surface finishes are changing), and Final (after all finishes, fixtures, trim are in place). Most remodels require 3–4 inspections over 4–8 weeks. Portsmouth inspectors are known for thorough reviews: bring the waterproofing detail drawing (showing cement board + membrane thickness, joint taping, curing time), the AFCI/GFCI one-line diagram, and the exhaust-duct routing sketch to the rough-electrical and rough-plumbing inspections to avoid delays. The city does not allow work to proceed until inspection is signed off, and violations (e.g., wrong waterproofing assembly, missing GFCI devices, duct terminating to attic) must be corrected immediately—rework inspections are free but take another 5–7 business days to schedule.

Three Portsmouth bathroom remodel (full) scenarios

Scenario A

Moving toilet and sink; new exhaust fan; same tub location — Strawbery Banke historic area

You're gutting a first-floor powder room in a pre-1978 home within Portsmouth's historic district (Strawbery Banke area). The existing toilet is flanged to the right wall; you want to move it to the left wall (new rough-in, new vent). The sink is relocating from the window wall to the far corner (new supply and drain lines). The exhaust fan is being replaced with a larger model and ducted to the roof (old ductwork routed to soffit, which is not code-compliant). Waterproofing around the sink backsplash will use cement board + acrylic membrane. Permit required: YES. Here's why: fixture relocation (toilet and sink) triggers IRC R101.2, new exhaust fan with exterior duct triggers M1505.1, and relocating the toilet vent may require adjusting the main vent stack (Rough Plumbing inspection will confirm trap-arm length and vent sizing). The historic district overlay adds a complication: you must obtain a Certificate of Appropriateness (COA) from the Portsmouth Planning Board BEFORE applying for the building permit—this is unusual in non-historic areas and adds 2–4 weeks. The COA reviews aesthetic impact (e.g., where the exhaust duct exits the roof, whether the new configuration is visible from the street); this is not a code review, but it's mandatory. Once COA is issued, submit the building permit application with plans showing: (1) toilet flange location (old and new), vent-stack size and routing, trap-arm length from trap to vent (must be ≤5 feet for 1.5-inch trap); (2) sink supply and drain routing with P-trap depth and vent tie-in; (3) exhaust fan CFM rating (≥50 CFM for bathroom), duct diameter (typically 4 inches), and roof termination detail (showing hood, damper, clearance above roof line). During Rough Plumbing, the inspector will measure trap-arm length and check vent sizing (per IRC P3005.2 and P3103.2). During Rough Electrical, GFCI protection on all receptacles and AFCI on the branch circuit must be shown. Waterproofing detail (cement board + membrane, or alternative approved assembly) must be marked on the plan or submitted separately. Permit fee: ~$350–$450 (1% of valuation, estimated $35,000–$45,000 for the full remodel). Inspection fees: $75 Rough Plumbing, $75 Rough Electrical, $75 Final = $225. COA (if required): $25–$50. Total cost to get permitted: ~$450–$700 before any actual construction. Timeline: COA review 2–4 weeks, building permit review 5–10 days, inspections 4–8 weeks. RRP (lead-paint) containment required if pre-1978 paint is disturbed.

Scenario B

Tub-to-shower conversion with new waterproofing assembly — second-floor full bath, non-historic zone

You're converting a 5-foot alcove tub to a walk-in shower in a second-floor full bathroom of a 1990s suburban home in Portsmouth (not historic district). The new shower will have a tile surround (cement board + acrylic membrane) and a linear drain on the floor (sloped to drain). The existing plumbing rough-in (supply valves, drain stub) can stay in place—no fixture relocation. You're NOT adding a new exhaust fan or changing electrical. The main permit trigger here is IRC R702.4.2 (waterproofing assembly for shower surrounds)—replacing a tub with a shower means a different waterproofing system, which requires plan-review and inspection approval. Permit required: YES, even though fixtures aren't moving, because the waterproofing assembly type changes. The city's code enforcement specifically calls out tub-to-shower conversions as requiring a permit and waterproofing detail submission. This is a common misconception: homeowners often assume 'same plumbing, same location' means no permit, but the assembly change triggers it. You must submit: (1) cross-section detail showing existing walls, new cement-board thickness (typically 1/2 inch on studs, or 1.25 inches if replacing damaged drywall), acrylic waterproofing membrane spec (thickness, coverage, cure time, e.g., 3mm liquid or 60-mil sheet), tile substrate, grout spec, and caulk at corners (per ANSI A108.01). (2) Linear drain specification and slope drawing (typically 1/4 inch per foot toward drain). (3) If the shower pan is new, a pan-liner spec or pre-formed pan detail. The city's Building Department requires this detail BEFORE issuing the permit—it's not approved as a 'standard detail'; every shower must be documented because improper waterproofing is the #1 source of post-permit complaints (water intrusion, mold, structural damage). Permit fee: ~$250–$350 (smaller project, lower valuation ~$15,000–$20,000). Inspections: Drywall inspection (after cement board is installed, before membrane application—this is crucial because inspectors verify board thickness and stud spacing), Waterproofing/Tile inspection (after membrane is applied and cured, before tile, to verify continuity and sealing at drains and penetrations), and Final (after tile and grout). Timeline: 5–10 days plan review, 4–6 weeks construction + inspections (the waterproofing membrane cure time alone is 3–7 days, depending on product). RRP rules apply if pre-1978 drywall/paint is cut. Common rejection: submitting a waterproofing detail that shows only 'tile + mortar' without an actual membrane layer—inspectors will reject and request a revised plan. Another rejection: proposing a vinyl or TPO liner without an approved detail—Portsmouth requires either liquid membrane or sheet membrane per ANSI, not plastic liners (though some inspectors will allow a pre-formed shower pan if manufacturer's documentation is attached).

Permit required (waterproofing assembly change) | Cement board + acrylic membrane detail required before permit issuance | Drywall inspection required (board thickness + stud spacing) | Waterproofing/tile inspection required (membrane continuity + drain sealing) | Permit $250–$350 | Inspections $225 | Total permit cost $475–$575 | Timeline 4-6 weeks including membrane cure

Scenario C

Vanity and toilet replacement in place; new tile surround, no plumbing/electrical change — owner-builder exempt scenario

You're refreshing a main-floor half-bath: removing the old pedestal sink and replacing it with a new pedestal sink in the exact same location (same supply valves, same P-trap location under the same flange). Removing the existing toilet and installing a new low-flow toilet in the same flange location (wax ring swap, no vent or supply-line change). Keeping the existing vanity light and GFCI outlet as-is. Removing old vinyl wallpaper and adding new tile tile wainscot (6 inches high) over the existing drywall (no new cement board, no waterproofing—just thin-set and grout on drywall, which is cosmetic). No changes to exhaust ventilation (none exists). Permit required: NO. This is pure cosmetic fixture refresh. IRC R101.2 exemptions explicitly exclude fixture replacement in the same location and interior finish work (flooring, tile, paint, wallpaper). The city's FAQ confirms: 'Replacing a toilet or sink with a new fixture in the same location without moving supply or drain lines does not require a permit.' However, important nuance: if you're tiling the surround in a shower area (not this scenario, but worth noting for comparison), that triggers the waterproofing assembly rule and DOES require a permit. But for a tile wainscot on drywall (not in a wet-spray zone around a tub or shower), this is exempt. You do not need to file any paperwork, no permit fee, no inspections. You can hire a handyman or DIY this work. Cost to file/permit: $0. Timeline: immediate, no delays. Lead-paint RRP applies only if you're disturbing existing paint (removing old wallpaper may or may not count; if the wallpaper contains paint, containment is recommended, but if it's pure paper, you're likely exempt—check with an RRP-certified contractor if pre-1978). This scenario exemplifies the narrow exemption: if you add ANY fixture movement, new electrical circuit, new exhaust duct, or waterproofing assembly change, it flips to permit-required. But pure swap + tile finish = exempt.

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Waterproofing details and common rejection triggers in Portsmouth

The single biggest reason for permit rejection in Portsmouth bathroom remodels is inadequate or missing waterproofing specification. IRC R702.4.2 requires a continuous, impermeable membrane in shower and tub surrounds, but the code does not mandate one specific product—it allows cement board + liquid membrane, cement board + sheet membrane, pre-formed shower pans, or proprietary waterproof drywall (like Durock or USG DensArmor Plus) as long as the assembly is sealed and sloped. Portsmouth inspectors, however, require a written detail showing: (1) substrate type (cement board, tile backer board, or waterproof drywall with thickness); (2) membrane type and thickness (e.g., '3mm liquid acrylic membrane per ANSI A108.02' or '60-mil sheet membrane'); (3) sealing at all penetrations (faucets, drains, pipe passes) using sealant tape or caulk; (4) slope or pan depth to drain; (5) cure time before tile application (liquid membranes often require 3–7 days). Submitting a plan that says 'tile on cement board' without specifying the membrane product will be rejected. Submitting a plan that proposes drywall + thin-set + tile (without a membrane layer) will be rejected. The city has seen too many post-project mold and water-intrusion complaints, so inspectors now verify the membrane product is actually in place during the Drywall/Waterproofing inspection (before tile is laid). If you're using a liquid membrane, the inspector will ask to see the product label and may request a material data sheet (to confirm it meets ANSI A108.01 or A108.02). If you're using a sheet membrane, the inspector will check seams are overlapped and sealed. One trick to avoid rejection: get the waterproofing product spec and ANSI rating from your contractor or tile supplier BEFORE submitting the permit plan. Include the product name, thickness, and ANSI standard in the written detail section of your plans. Inspectors in Portsmouth are detail-oriented and will verify the product exists and is rated correctly.

GFCI and AFCI protection: Portsmouth's electrical code enforcement

New Hampshire Building Code adoption of the 2020 NEC is strict on GFCI (Ground Fault Circuit Interrupter) and AFCI (Arc-Fault Circuit Interrupter) protection in bathrooms, and Portsmouth's Building Department enforces it rigorously. NEC 210.8(A)(1) requires GFCI protection for all receptacles in bathrooms (defined as a room with a sink, toilet, or shower/tub). NEC 210.12(B) requires AFCI protection for all circuits in bathrooms (branch circuit protection). When you add a new exhaust fan, heated towel rail, or bathroom lighting, the circuit must be on an AFCI breaker or outlet, which means the main panel must have an AFCI breaker installed (or GFCI/AFCI combo outlets used). Portsmouth inspectors will request a one-line electrical diagram showing: (1) which breaker the new bathroom circuits are on; (2) whether that breaker is an AFCI type; (3) which outlets are protected (all of them should be listed and GFCI-protected, either by a GFCI breaker or individual GFCI outlets). If the plan doesn't show AFCI/GFCI details, it will be rejected and sent back for correction—this is not a 'we'll just assume it' situation. During the Rough Electrical inspection, the inspector will open the main panel and verify the AFCI breakers are installed and correctly labeled. If existing breakers are standard type (not AFCI), the inspector will ask for an upgrade. Many remodelers skip this step and try to get away with it; Portsmouth will stop the work. Cost impact: an AFCI breaker retrofit typically runs $150–$300 if you add it mid-project; upfront installation (during permit planning) costs the same but avoids delays. For a full-bath remodel with new lighting, exhaust fan, and possible heated towel rail, you should plan for at least one dedicated AFCI circuit, likely two. Include this in your electrical estimate.

City of Portsmouth Building Department
Portsmouth City Hall, 1 Junkins Avenue, Portsmouth, NH 03801
Phone: (603) 610-7242 (Building Inspector's Office) — verify current number on city website | https://www.ci.portsmouth.nh.us/building-permits (online submission available; check site for current portal link)
Monday–Friday 8:00 AM–5:00 PM; closed major holidays

Common questions

Can I do a bathroom remodel myself without a contractor if I'm the homeowner?

Yes, if your home is owner-occupied (primary residence), you can pull the permit as owner-builder and do the work yourself. However, you must still obtain the permit, pass all inspections, and follow code. Plumbing and electrical rough-ins must meet IRC and NEC standards; inspectors will verify this. Many homeowners hire plumbers and electricians for rough-ins (the code requires licensed trades in NH for these specific tasks) and do demolition, framing, drywall, tile, and trim themselves. You cannot legally perform plumbing or electrical rough-in work yourself unless you're a licensed trades person (or the homeowner performing limited unpermitted work, which would void the permit). Bottom line: owner-builder permits are allowed, but the work must still pass inspection.

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

Plan review typically takes 5–10 business days if your application is complete (all plans, waterproofing detail, electrical diagram). If the submission has missing info, it goes back to you for revision, adding another 5–10 days. Resubmissions are typically reviewed faster (3–5 days) if corrections are minor. Once approved, you can begin. Total inspections (Rough Plumbing, Rough Electrical, Drywall/Waterproofing, Final) take 4–8 weeks depending on your contractor's schedule and inspection availability—inspections are usually scheduled on 2–3 day notice. If it's a historic-district project, add 2–4 weeks for the COA (Certificate of Appropriateness) review before you even apply for the building permit.

What is the permit fee for a bathroom remodel in Portsmouth?

Portsmouth uses a percentage-of-valuation fee schedule: typically 0.75–1.2% of the estimated project cost. For a $30,000 full-bath remodel, expect $225–$360 in permit fees. Add $75 per inspection (Rough Plumbing, Rough Electrical, Final = 3 inspections, $225 total). A drywall or waterproofing inspection may add another $75. Total permit and inspection cost: $300–$600. If you're in a historic district, add a $25–$50 COA fee. Get a pre-permit cost estimate from the Building Department by calling with your project scope and estimated cost.

Do I need a permit if I'm just replacing my toilet and vanity with new ones in the same spot?

No. Replacing fixtures in the existing location without moving supply or drain lines is exempt from permitting. This includes toilet swap (old wax ring, new toilet in same flange), pedestal or vanity sink replacement in the same location, faucet upgrade, and light fixture swap. The exemption applies as long as no plumbing lines are disturbed, no electrical circuits are added, and no walls are moved. If you move the fixture to a new location, you need a permit.

Can the exhaust fan ductwork go to my attic instead of the exterior?

No. IRC M1505.1 and Portsmouth code require all bathroom exhaust fans to be ducted to the exterior (roof or wall), not to an attic or soffit. Ducting to an attic violates code and will fail inspection—the duct must terminate outside with a damper to prevent cold-air backdrafting. This is a common code violation in older homes and one of the first things inspectors check during rough inspection. If your home has an existing fan ducted to the attic, converting it to exterior duct during a remodel is often required by inspectors.

What is the most common reason bathrooms get rejected during plan review in Portsmouth?

Incomplete or missing waterproofing detail. Submitting a plan that shows 'tile surround' without specifying the membrane type (liquid vs. sheet), thickness, and ANSI rating will be rejected. The city requires a written detail showing substrate, membrane product, sealing at penetrations, and cure time. Second most common: missing GFCI/AFCI electrical details on the one-line diagram. Make sure your plan shows which circuits have AFCI breakers and which outlets are GFCI-protected. Include product specs for both.

Is a bathroom remodel in a pre-1978 home subject to lead-paint rules?

Yes. If your home was built before 1978, the federal RRP (Renovation, Repair, Painting) rule applies. If you're removing paint, sanding drywall, or disturbing painted surfaces, you must either hire an EPA-certified RRP contractor or follow containment protocols yourself (not recommended unless trained). This is a federal rule, not Portsmouth-specific, but it applies to all bathroom remodels in older homes. Lead-paint disclosure and containment are required before work begins. Portsmouth inspectors will often ask about RRP compliance during the initial inspection if the home is pre-1978.

Do I need a permit to convert a tub to a shower?

Yes. Even if the plumbing rough-in (supply and drain) stays in the same location, changing from a tub to a shower changes the waterproofing assembly, which triggers a permit. IRC R702.4.2 requires a different waterproofing detail for showers (typically cement board + acrylic membrane, with slope or pan to drain) versus tubs. The city requires a written waterproofing detail before approval. This is a very common remodel, and Portsmouth inspectors see it often—expect detailed review of the shower-pan slope and membrane sealing.

Can I move my toilet to a different wall in the bathroom without a major plumbing overhaul?

Maybe, but it requires a permit. Moving a toilet to a new location means a new drain flange, new vent-stack tie-in (or vent relocation), and new supply line routing. The trap arm (distance from trap to vent) must not exceed code limits (per IRC P3005.2: 5 feet for 1.5-inch, 10 feet for 2-inch trap). If your new location is more than 5 feet from the existing vent, you'll need to reroute the vent stack or install a new one, which is more complex and costly. A plumber can assess this during a pre-permit consultation. The permit is required; rough-plumbing inspection will verify trap-arm length and vent sizing.

What happens during the rough-plumbing inspection for my bathroom remodel?

The inspector will verify: (1) new drain lines are sloped properly (typically 1/4 inch per foot toward the main drain); (2) trap-arm length from trap to vent is within code limits; (3) vent-stack sizing and routing to the roof; (4) P-traps are properly sealed and accessible; (5) supply lines are correctly sized and protected; (6) any new cleanout plugs are accessible. The inspector will measure trap-arm distance and may ask you to open walls if rough-ins are not visible. Bring your plumbing plan to the inspection so the inspector can verify it matches the work. Common issues: trap arm too long (exceeds code), vent too small (not sized for fixture load), missing trap sealing, or improper slope. These must be corrected before the inspector signs off.

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 Portsmouth Building Department before starting your project.

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