Do I Need a Permit to Replace a Water Heater in Idaho?
Water heater replacement permit requirements. Yes, even for like-for-like swaps. What inspectors check and how to pass.
Yes — even for a like-for-like replacement.
Idaho-specific rules
Adopted code: 2018 International Mechanical Code (IMC) and 2018 International Fuel Gas Code (IFGC), part of Idaho's statewide baseline under the Idaho Building Code Act, effective January 1, 2021 — these govern venting, combustion air, and gas-fuel-fired water heater installations statewide. The plumbing connection (water lines, drain/relief-valve discharge piping) is governed by the plumbing code your local jurisdiction has adopted, which is not part of this statewide baseline — confirm the applicable plumbing code and any local amendments with your building department.
Why a Simple Swap Needs a Permit
Most jurisdictions require a permit for all water heater replacements, even when you're installing the same type and size. The permit ensures proper venting, gas connections, temperature/pressure relief valve discharge, and seismic strapping. Improper water heater installations are a leading cause of residential CO poisoning and water damage.
What Inspectors Check
The inspector will verify: gas line connections and drip leg (sediment trap), proper venting (metal B-vent for standard, PVC for high-efficiency), T&P relief valve discharging to within 6 inches of the floor or exterior, seismic strapping (two straps — upper and lower third), and adequate combustion air supply.
Tankless Conversion
Converting from a tank to tankless water heater often requires additional work: a larger gas line (tankless units draw more BTUs), PVC venting (most tankless units are high-efficiency), and potentially an electrical outlet for the unit. This may trigger both plumbing and gas permits.
DIY vs. Hiring a Plumber
Many jurisdictions allow homeowners to replace their own water heater in their primary residence — confirm with your city. You still must pull the permit and pass inspection. Most homeowners hire a licensed plumber because the permit and inspection process is simpler when the contractor handles it.
Yes, you need a $40-$60 permit. It's a quick same-day approval and one final inspection. Don't skip it — it protects you and your home.
Permit fees by city in Idaho
Verified from each city’s published fee schedule. Where a city has no separate fee listed for this project, open the city page for the current requirements and amount.
| City | Permit fee | Source |
|---|---|---|
| American Falls | $23.50Verifiedvia Consolidated Building-Development Permit (New Construction, Additions, Alterations, Repairs, Moving, Demolition, Signs, Grading) | Consolidated Building-Development Permit (New Construction, Additions, Alterations, Repairs, Moving, Demolition, Signs, Grading) → |
| Ammon | $160.00 (includes 3 inspections)Verified | Plumbing Permit → |
| Blackfoot | $100Verifiedvia Residential Building Permit (New Construction / Addition / Remodel) | Residential Building Permit (New Construction / Addition / Remodel) → |
| Boise | $55Verified | Water Heater Permit → |
| Buhl | $23.50Verifiedvia Building Permit (Residential New Construction, Additions, Remodels, Repairs) | Building Permit (Residential New Construction, Additions, Remodels, Repairs) → |
| Burley | $130.00Verified | Plumbing Permit → |
| Caldwell | $160.00 per dwelling unitVerified | Residential Plumbing Permit → |
| Cascade | 40% of the building permit fee (65% of the building permit fee if an outside plan reviewer is used)Verifiedvia Residential Building Permit | Residential Building Permit → |
| Chubbuck | $30.00Verified | Plumbing Permit → |
| City of St. Maries | $24.00Verifiedvia Building Permit | Building Permit → |
| Coeur d'Alene | $10.00 per item (quantity x $10)Verified | Plumbing Permit → |
| Donnelly | $24.00Verifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Driggs | $305Verifiedvia Residential Building Permit | Residential Building Permit → |
| Eagle | Cost up to $20,000: multiply by 3% plus $60; cost $20,001–$100,000: subtract $20,000, multiply by 2%, plus $660; cost over $100,001: subtract $100,000, multiply by 1%, plus $2,260Verified | Plumbing Permit → |
| Emmett | See city page for the current Residential Building Permit fee | Residential Building Permit → |
| Fruitland | $23.50Verifiedvia Building Permit (New Construction, Additions, Remodels) | Building Permit (New Construction, Additions, Remodels) → |
| Garden City | $150.00Verifiedvia Residential Building Permit (New Construction / Addition / Remodel) | Residential Building Permit (New Construction / Addition / Remodel) → |
| Grangeville | $15.00Verifiedvia Residential Building Permit (New Construction, Additions, Alterations, Repairs) | Residential Building Permit (New Construction, Additions, Alterations, Repairs) → |
| Greenleaf | $50.00 flat, due upon submission of all building permit applicationsVerifiedvia Residential Building Permit (New Construction / Addition / Alteration) | Residential Building Permit (New Construction / Addition / Alteration) → |
| Hailey | $27.78Verifiedvia Building Permit (New Construction, Additions, Remodels — Commercial & Residential) | Building Permit (New Construction, Additions, Remodels — Commercial & Residential) → |
| Harrison | Per Table 1-A of the 1997 Uniform Building Code, applied to project valuation determined from ICBO Building Valuation Data (or the most recent available data if that publication has been discontinued)Verifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Hayden | $130 / $195 / $260 / $325 / $325 plus $65 per additional 1,000 sq ft or portion thereofVerified | Plumbing Permit (State-Issued — Idaho DOPL, not the City) → |
| Heyburn | See city page for the current Residential Home Permit (New Construction — Single Family, Duplex, Zero Lot Line, Townhouse) fee | Residential Home Permit (New Construction — Single Family, Duplex, Zero Lot Line, Townhouse) → |
| Idaho City | $23.50Verifiedvia Residential Building Permit (New Construction, Additions & Alterations) | Residential Building Permit (New Construction, Additions & Alterations) → |
| Idaho Falls | $5.10 per installationVerified | Plumbing Permit → |
| Jerome | $23.50Verifiedvia Residential Building Permit | Residential Building Permit → |
| Kellogg | See city page for the current Residential Building Permit (New Construction / Addition / Alteration) fee | Residential Building Permit (New Construction / Addition / Alteration) → |
| Ketchum | $130Verified | Plumbing Permit (State of Idaho) → |
| Kimberly | $150.00Verifiedvia Building Permit (New Construction, Additions, Remodels, Repairs, Demolition, Re-Roof) | Building Permit (New Construction, Additions, Remodels, Repairs, Demolition, Re-Roof) → |
| Kootenai County | $130 / $195 / $260 / $325 / $325 plus $65 per additional 1,000 sq ft or portion thereofVerified | Plumbing Permit (State-Issued — Idaho DOPL, not the County) → |
| Kuna | $130Verified | Plumbing Permit → |
| Lewiston | $216.56, plus $72.20 for each additional 1,000 sq ft or portion thereofVerified | Plumbing Permit → |
| Malad City | See city page for the current Residential Building Permit (New Construction / Addition / Accessory) fee | Residential Building Permit (New Construction / Addition / Accessory) → |
| Melba | See city page for the current Residential Building Permit (New Dwelling / Addition / Remodel) fee | Residential Building Permit (New Dwelling / Addition / Remodel) → |
| Meridian | $30 per unit base fee, plus $8 per fixtureVerified | Residential Plumbing Permit → |
| Middleton | $130.00Verified | Plumbing Permit → |
| Minidoka County (Building Authority for Unincorporated County and the Cities of Acequia, Minidoka, Paul, and Rupert) | See city page for the current Residential Building Permit (New Construction, Addition, Remodel) fee | Residential Building Permit (New Construction, Addition, Remodel) → |
| Moscow | $27.50Verifiedvia Residential Building Permit (New Single-Family Dwelling / Addition) | Residential Building Permit (New Single-Family Dwelling / Addition) → |
| Mountain Home | See city page for the current Residential Building Permit (New Construction) fee | Residential Building Permit (New Construction) → |
| Nampa | $180.00 per dwelling unitVerified | Residential Plumbing Permit → |
| Notus | See city page for the current Residential Building Permit (New Construction, Additions, Remodels) fee | Residential Building Permit (New Construction, Additions, Remodels) → |
| Osburn | $140.00 per sq. ft. (valuation input)Verifiedvia Residential Building Permit (New Construction / Addition / Alteration) | Residential Building Permit (New Construction / Addition / Alteration) → |
| Payette | $24Verifiedvia Residential Building Permit | Residential Building Permit → |
| Plummer | $23.50Verifiedvia Residential Building Permit | Residential Building Permit → |
| Pocatello | $130Verified | Plumbing Permit → |
| Post Falls | $35.00Verified | Plumbing Permit → |
| Preston | Set by city inspector, based on valuationVerifiedvia Building Permit (New Construction / Additions / Accessory Buildings) | Building Permit (New Construction / Additions / Accessory Buildings) → |
| Priest River | Per Table 1-A of the 1997 Uniform Building Code (valuation-based)Verifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Rathdrum | See city page for the current Plumbing Permit (State-Issued — Idaho DOPL, not the City) fee | Plumbing Permit (State-Issued — Idaho DOPL, not the City) → |
| Rexburg | $130.00Verified | Plumbing Permit → |
| Rigby | $26.46Verifiedvia Residential Building Permit (Single-Family Dwelling, Townhouse, New Construction & Additions) | Residential Building Permit (Single-Family Dwelling, Townhouse, New Construction & Additions) → |
| Rupert | Calculated from Project Value using the Building Department's fee schedule; no dollar-per-valuation-bracket table was found published onlineVerifiedvia Residential Building Permit | Residential Building Permit → |
| Salmon | $24Verifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Sandpoint | $61.10Verifiedvia Residential Building Permit (New Single-Family Construction) | Residential Building Permit (New Single-Family Construction) → |
| Shelley | $21.00Verifiedvia Building Permit (New Construction, Additions, Remodels) | Building Permit (New Construction, Additions, Remodels) → |
| Soda Springs | $25.00Verifiedvia Residential Building Permit (New Construction / Addition / Remodel) | Residential Building Permit (New Construction / Addition / Remodel) → |
| Spirit Lake | See city page for the current Plumbing Permit (State-Administered) fee | Plumbing Permit (State-Administered) → |
| Star | $130.00Verified | Plumbing Permit → |
| Twin Falls | $120.00Verified | Plumbing Permit (MEP) → |
| Unincorporated Ada County | Valuation-based per Ada County 2025 Fee Schedule (Resolution 3149, effective November 2025); see Building-Fees.pdf at adacounty.id.gov/developmentservices/permitting-division/fees/Verifiedvia Residential Building Permit (New Construction / Addition) | Residential Building Permit (New Construction / Addition) → |
| Unincorporated Bannock County | $23.00Verifiedvia Residential Building Permit (New Construction / Addition) | Residential Building Permit (New Construction / Addition) → |
| Unincorporated Bingham County | $1–$500: $16.50 | $501–$2,000: $16.50 + $2.20/each add'l $100 | $2,001–$25,000: $49.50 + $9.90/each add'l $1,000 | $25,001–$50,000: $277.30 + $7.15/each add'l $1,000 | $50,001–$100,000: $455.95 + $4.95/each add'l $1,000 | $100,001–$500,000: $762.85 + $3.85/each add'l $1,000 | $500,001–$1,000,000: $2,243.45 + $3.30/each add'l $1,000 | $1,000,001–$5,000,000: $3,915.45 + $2.20/each add'l $1,000Verifiedvia Residential Building Permit (New Construction / Addition / Remodel) | Residential Building Permit (New Construction / Addition / Remodel) → |
| Unincorporated Bonneville County | See city page for the current Residential Building Permit (New Construction / Addition) fee | Residential Building Permit (New Construction / Addition) → |
| Unincorporated Canyon County | $280.00Verifiedvia Residential Building Permit (New Construction / Addition / Remodel) | Residential Building Permit (New Construction / Addition / Remodel) → |
| Unincorporated Cassia County | Calculated based on square footage using the IBC 2003 Valuation Table 1Verifiedvia Residential Building Permit (New Construction / Addition) | Residential Building Permit (New Construction / Addition) → |
| Unincorporated Elmore County | $100.00Verifiedvia Residential Building Permit (New Construction / Addition) | Residential Building Permit (New Construction / Addition) → |
| Unincorporated Franklin County | 1% of the assessed value of the proposed buildingVerifiedvia Residential Building Permit (New Construction / Remodel Changing Outside Dimensions) | Residential Building Permit (New Construction / Remodel Changing Outside Dimensions) → |
| Unincorporated Gem County | $1–$500: no fee listed at base tier; $501–$2,000: $23.50 for the first $500 plus $3.05 for each additional $100 or fraction thereof; $2,001–$25,000: $69.25 for the first $2,000 plus $14.00 per additional $1,000 or fraction; $25,001–$50,000: $391.25 for the first $25,000 plus $10.10 per additional $1,000; $50,001–$100,000: $643.75 for the first $50,000 plus $7.00 per additional $1,000; $100,001–$500,000: $993.75 for the first $100,000 plus $5.60 per additional $1,000; $500,001–$1,000,000: $3,233.75 for the first $500,000 plus $4.75 per additional $1,000; $1,000,001+: $5,608.75 for the first $1,000,000 plus $3.65 per additional $1,000Verifiedvia Residential Building Permit (New Construction / Addition / Alteration) | Residential Building Permit (New Construction / Addition / Alteration) → |
| Unincorporated Jefferson County | $26.46Verifiedvia Residential Building Permit (Single-Family Dwelling / New Construction, Additions, ADUs) | Residential Building Permit (Single-Family Dwelling / New Construction, Additions, ADUs) → |
| Unincorporated Latah County | $50.00 flatVerifiedvia Residential/General Building Permit | Residential/General Building Permit → |
| Unincorporated Madison County | $500 for dwellings/non-accessory structures; $100 for accessory structuresVerifiedvia Residential Building Permit (New Construction / Addition / Accessory Structure) | Residential Building Permit (New Construction / Addition / Accessory Structure) → |
| Unincorporated Nez Perce County | $112.65 per sq ft (minimum)Verifiedvia Single Family Residence Building Permit | Single Family Residence Building Permit → |
| Unincorporated Power County | $24 for valuation $1–$500; $24 + $3 per additional $100 (or fraction) up to $2,000; $69 + $11 per additional $1,000 up to $40,000; $487 + $9 per additional $1,000 up to $100,000; $1,027 + $7 per additional $1,000 up to $500,000; $3,827 + $5 per additional $1,000 up to $1,000,000; $6,327 + $3 per additional $1,000 up to $5,000,000; $18,327 + $1 per additional $1,000 above $5,000,000Verifiedvia Residential Building Permit (New Construction / Addition) | Residential Building Permit (New Construction / Addition) → |
| Unincorporated Twin Falls County | $82.65 per sq ft (Single Family Home); Finished Basement $42.78/sq ft; Unfinished Basement $32.29/sq ft; Carport/Lean-to $32.12/sq ft; Ag Shop/Res Shop $41.71/sq ft; Deck/Covered Porch/Patio $18.66/sq ftVerifiedvia Residential Building Permit (New Construction / Addition) | Residential Building Permit (New Construction / Addition) → |
| Unincorporated Valley County | See city page for the current Residential Building Permit (New Construction / Addition / Alteration) fee | Residential Building Permit (New Construction / Addition / Alteration) → |
| Victor | $22.50Verifiedvia Standard Building Permit (Residential New Construction) | Standard Building Permit (Residential New Construction) → |
| Wallace | See city page for the current Residential Building Permit (New Construction / Addition / Alteration) fee | Residential Building Permit (New Construction / Addition / Alteration) → |
| Wilder | $24.00Verifiedvia Residential Building Permit (New Construction / Addition / Remodel / Accessory Structure) | Residential Building Permit (New Construction / Addition / Remodel / Accessory Structure) → |
| Worley | $23.50 for valuation $1-$500; $23.50 for the first $500 plus $3.05 per additional $100 (or fraction) to $2,000; $69.25 for the first $2,000 plus $14 per additional $1,000 to $25,000; scaling further per Table 1-A for higher valuationsVerifiedvia Residential Building Permit | Residential Building Permit → |