Bolthole Index

Washington County, Idaho

Building permits, zoning and septic rules in Washington County, Idaho

63Index Score / 100
#18 of 44 in Idaho

Unincorporated Washington County, Idaho requires a building permit before covered construction, alterations or occupancy changes1. Washington County Planning & Zoning handles county building applications and land-use review; Cambridge has its own building permits and zoning2345. Southwest District Health handles septic permits, including for Cambridge properties using individual septic systems67.

At a glance

Building permit
Required for covered work in unincorporated Washington County before work begins1
Zoning
County zoning applies to unincorporated land; Cambridge sets zoning for the city and its designated impact area835
Septic permit
Southwest District Health issues installation permits; septic repairs and expansions also generally require approval69
RV living
Transient RV stays in manufactured/mobile-home parks are capped at 3 months; private-lot occupancy remains unconfirmed102
Tiny homes
No tiny-home-specific occupancy rule was confirmed; ordinary building, zoning and septic review still applies where relevant11112
Owner-builder
Owners may be exempt from Idaho contractor registration, but Washington County's building permit and inspections still apply13
Private well
An Idaho Department of Water Resources drilling permit is required before drilling14
Manufactured home
A certificate of occupancy is required; the manufactured-home definition includes size criteria and a HUD-certification exception1516

Who to call

Building permits

Washington County Planning & Zoning

Building permit applications, planning and zoning review, and county building inspections

208-414-3631

256 East Court, Weiser, ID 83672

Septic permits

Southwest District Health - Septic & Land Development

Septic-tank and drainfield permits, site evaluations, and septic-system oversight in Washington County

208-455-5400

Online permits →

Roads & driveways

Washington County Road & Bridge

County-road approach access, right-of-way and utility permit applications

208-414-0950

1102 E Court Street, Weiser, ID 83672

Online permits →

Contact details are copied from each office’s official page and were checked against it on October 12, 2026.

Off-grid gear

Going off-grid in Washington County means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Washington County, Idaho?

Yes. In unincorporated Washington County, an owner or authorized agent must apply before constructing, enlarging, altering, repairing, moving or demolishing a building or structure, or changing its occupancy1. The permit is issued only when the plans, specifications and completed project conform to the zoning title and adopted codes1. The county has adopted building and fire codes, and new buildings must meet applicable standards17. For a residential dwelling, the county requires the applicable sewer-system permit and approval of a county-road culvert and driveway approach before issuing the building permit118. Electrical, plumbing and HVAC work requires separate trade permits when performed19. Covered projects also require final building inspections and a certificate of occupancy2021.

Who issues building permits in Washington County, Idaho?

Washington County Planning & Zoning accepts county building-permit applications at 256 East Court, Weiser, ID 83672; call 208-414-36312. The county building rules here apply to unincorporated land; inside Cambridge, the city issues building permits, while individual septic systems still require public health district permits through Southwest District Health1476. County hearing applications must be accepted and fees paid in time for at least 3 weeks of legal notice; start at least 4 weeks before the hearing22. Subdivision applications carry an application fee plus applicable zone-change or special-use fees; we could not confirm the amounts, so request a project-specific fee estimate from Planning & Zoning232. For a residential county-road approach, call Road & Bridge at 208-414-0950 for the road supervisor’s required culvert and approach approval before the building permit1824.

Does Washington County, Idaho have zoning?

Washington County administers zoning for unincorporated land and publishes a zoning map and county code811. Cambridge sets its own zoning for the city and designated impact area; individual septic permits remain with the public health district, Southwest District Health576. Its districts include A1 Agricultural, A2 Agricultural Transitional, C1 and C2 Commercial, D1 Light Industrial, D2 Heavy Industrial and R Recreation25. The Planning and Zoning Commission hears land-use and zoning matters, including rezones, variances, special uses and subdivisions3. Dimensional rules depend on the district: A1 and A2 structures generally sit at least 15 feet from property boundaries and street rights-of-way and 100 feet from state or federal highways, while commercial and industrial districts have different setbacks26. Maximum building height is 35 feet in A1, A2 and C1, 45 feet in C2, and 100 feet in D1 and D2, subject to special-permit treatment for towers and similar structures27. We could not confirm a general minimum dwelling size for site-built homes or a minimum lot size for ordinary parcels; ask Planning & Zoning for the parcel's district standards2.

How do septic permits work in Washington County, Idaho?

Southwest District Health issues septic installation permits in Washington County and conducts an on-site evaluation before issuing a permit; call 208-455-5400 before designing the system628. Installing, modifying, repairing or expanding a septic system generally requires a valid installation permit, with specific state exceptions9. Owners installing their own standard or basic alternative systems may qualify for an installer-permit exemption; that exemption does not waive the system’s installation permit9. Ask Southwest District Health whether a proposed repair qualifies for an exception before starting work928. The health district inspects installed systems; large soil-absorption systems also require DEQ review and inspection1229. Only 0.5% of county soils are rated without severe limitations for a conventional drain field, making site feasibility an early purchase question30. Extended Treatment Package systems require annual testing, inspection and maintenance by a licensed service provider31.

Can you live in an RV or tiny home in Washington County, Idaho?

Washington County limits transient RV use inside manufactured/mobile-home parks: no more than 10% of park sites may be designated for transient RVs, and a transient RV may stay no longer than 3 months10. That park rule does not answer whether someone may live in an RV on an ordinary private parcel, and we could not confirm a separate private-lot rule; ask Planning & Zoning at 208-414-3631 before relying on an RV during construction or as a residence2. We also could not confirm a tiny-home-specific occupancy rule; ask Washington County Planning & Zoning how the proposed home would be classified2. A tiny home that meets the county code's definition of a building or structure is subject to the ordinary building-permit framework in unincorporated Washington County, with county zoning review for unincorporated land138. A manufactured or mobile home used as a permanent residence must sit on a legal lot, meet placement requirements and receive a certificate of occupancy before anyone moves in15, and the manufactured-home definition includes a 600-square-foot erected-on-site criterion with a HUD-certification exception for homes that do not meet the size criteria16. Park-specific site-size, coverage and utility rules should not be generalized to an ordinary parcel323334.

How do you build a home in Washington County, Idaho?

  1. Ask Washington County Planning & Zoning to identify the zoning district, controlling setbacks and height limit before finishing the site plan252627.
  1. Obtain the public health district's site evaluation and septic installation permit required for the county building application121.
  1. Secure the correct road approval. For a residential driveway onto a county road, the county road supervisor must approve the culvert and approach before the building permit can be issued; a state-highway approach requires an Idaho Transportation Department encroachment permit1835.
  1. Apply to Planning & Zoning before construction begins and supply plans that conform to the zoning title and adopted codes1.
  1. Obtain separate electrical, plumbing and HVAC permits for that work19.
  1. Complete the county and trade inspections, have the public health district inspect the installed septic system, and obtain the certificate of occupancy202921.

What should you check before buying land in Washington County, Idaho?

Check septic feasibility first because only 0.5% of Washington County soils are rated without severe limitations for a conventional drain field30. Check terrain at the proposed homesite too: only 21% of county land is at a slope of 15% or less36. Idaho requires a drilling permit before a private well is drilled, and the well driller must be licensed14. Verify legal access and the correct road authority; a residential county-road approach needs county approval before the building permit, while a state-highway driveway requires a state encroachment permit1835. Ask Planning & Zoning whether subdivision plans need floodway or flood-fringe materials; we could not confirm a blanket countywide floodplain prohibition37. Finally, budget carrying costs using the county's roughly 0.5% effective property-tax rate and $1,316 median annual property-tax bill3839.

Watch-outs

  • Washington County requires the applicable sewer-system permit and county-road approval for a residential dwelling before issuing the building permit, so those reviews belong at the front of the schedule118.
  • Only 0.5% of Washington County soils are rated without severe limitations for a conventional drain field; secure the public health district's site evaluation before committing to a homesite3012.
  • The 3-month RV limit applies only to transient sites in manufactured/mobile-home parks; Washington County's rule for RV living on an ordinary private parcel could not be confirmed102.
  • Agricultural treatment is limited: qualifying improvements on land used exclusively for agriculture may fall outside the zoning title, but farm and ranch buildings still have stated setback rules40.
  • Idaho's contractor-registration exemption for owners who do their own work and do not plan to sell within 12 months does not waive Washington County's building permit13.

Sources

  1. 3-1-3: Building Permit Requirement, quoted and re-checked
  2. Washington County Planning & Zoning (co.washington.id.us)
  3. Hearing Information | Washington County, ID, quoted and re-checked
  4. Cambridge: 9-1-2: Building Permits Required (Washington County), quoted and re-checked
  5. Cambridge: official source (Washington County), quoted and re-checked
  6. Septic & Land Development, quoted and re-checked
  7. Cambridge: Septic and Septage (Washington County), quoted and re-checked
  8. Idaho Code § 67-6504 — Planning and zoning commission (Idaho statewide rule), quoted and re-checked
  9. IDAPA 58.01.03 Individual/Subsurface Sewage Disposal & Cleaning of Septic Tanks Rules, quoted and re-checked
  10. 5-16-1: Manufactured Home Parks, quoted and re-checked
  11. Planning & Zoning | Washington County, ID, quoted and re-checked
  12. Septic and Septage, quoted and re-checked
  13. Idaho Division of Occupational and Professional Licenses, Contractors FAQ, quoted and re-checked
  14. Wells, quoted and re-checked
  15. 3-3-6: Permitted Locations and Requirements, quoted and re-checked
  16. Washington County Code § 5-2-1, Definitions, quoted and re-checked
  17. Washington County Comprehensive Plan, quoted and re-checked
  18. 3-1-3: Building Permit Requirement, quoted and re-checked
  19. Frequently Asked Questions (FAQs) - Division of Occupational and Professional Licenses (Idaho statewide rule), quoted and re-checked
  20. Washington County New Building Permit Package, quoted and re-checked
  21. Washington County New Building Permit Package, quoted and re-checked
  22. Hearing Information, quoted and re-checked
  23. An Overview of Washington County’s Subdivision Process, quoted and re-checked
  24. Washington County Road & Bridge (co.washington.id.us)
  25. Planning & Zoning, quoted and re-checked
  26. 5-3-4: Setback Building Lines, quoted and re-checked
  27. 5-3-3: Maximum Height of Buildings and Structures, quoted and re-checked
  28. Southwest District Health - Septic & Land Development (swdh.id.gov)
  29. Septic and Septage, quoted and re-checked
  30. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
  31. Septic & Land Development – Southwest District Health, quoted and re-checked
  32. 5-16-1: Manufactured Home Parks, quoted and re-checked
  33. 5-16-1: Manufactured Home Parks, quoted and re-checked
  34. 5-16-1: Manufactured Home Parks, quoted and re-checked
  35. Types of Right-of-Way Encroachment Permits (Idaho statewide rule), quoted and re-checked
  36. Share of land at 15% slope or less: Bolthole Index county data
  37. An Overview of Washington County’s Subdivision Process, quoted and re-checked
  38. Effective property tax rate: Bolthole Index county data
  39. Median property tax bill: Bolthole Index county data
  40. 5-1-2: Scope, Interpretation and Application of Provisions, quoted and re-checked

Written October 12, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

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Compared with neighboring counties

Like all 6 of its neighbors, Washington County requires a building permit for a home.

RuleWashington CountyAdams CountyGem CountyPayette CountyValley CountyBoise CountyCanyon County
Building permitRequiredRequiredRequiredRequiredRequiredRequiredRequired
County zoningYesYesYesYesYesYesYes
Septic permitsSouthwest District HealthSWDHSouthwest District HealthSouthwest District HealthCentral District HealthCentral District HealthSouthwest District Health

County locator

Washington County in Idaho

63
County map
Washington County highlighted among the Idaho counties · colored by Index score

How Washington County scores

Seclusion84100% ev.
Self-Sufficiency43100% ev.
Admin Boringness3890% ev.
Durability42100% ev.
Property Autonomy90100% ev.
Carry Cost80100% ev.

Evidence strength: 98%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$398kTypical home
0.5%Property tax
$2,299Land / acre
20.7"Annual rain
16.2% of yrsSevere drought
12.9 / yr (+11)Mid-century 100°F days
35.8 daysMid-century dry spell
1.04" (+6.7%)Mid-century 1-day rain
1.16×Wildfire change factor
100%Forward climate coverage
$1,240Home insurance / yr
3.8% / yrInsurance growth
1.35%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
918People within 30 min
791,077People within 2 hr
1,891Radius comparison (15 mi)
7.9People / sq mi
37%Federal land
21%Land at 15% slope or less
0.5%Soils rated "not limited" for septic (strict USDA rating)
4,763 acWorkable land screen
16.5%Wooded land
45.5 tonsBiomass / forest ac
48.3°FAvg temp

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Cities and towns in Washington County

Inside a city or town, that city usually issues building permits and sets zoning; the county’s rules above cover unincorporated land. Septic, wells and floodplain rules usually stay with the county or state everywhere.

Not yet researched: Midvale

Answers from the rulebook for Washington County

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

Washington County rules

  • Building permitRequired

    Construction, enlargement, alteration, repair, movement, demolition, or occupancy change of a building or structure subject to the county code.

    • A state sewer-system permit is also required where applicable and is necessary to obtain a county building permit.
    • For a residential dwelling, county road-supervisor approval of culvert installation and driveway approach is required before and as a condition of obtaining the building permit.
    “Any owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure, or to cause any such work to be done, shall first make application to the planning and zoning administrator and/or building official, or other person designated by the board of county commissioners, and obtain the required permit.”
    One more reviewed finding on this topic
    • Required — Construction, enlargement, alteration, repair, movement, demolition, or occupancy change of a building or structure in unincorporated Washington County.
      “Any owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure, or to cause any such work to be done, shall first make application to the planning and zoning administrator and/or building official, or other person designated by the board of county commissioners, and obtain the required permit.”
  • Building code adoptedAdopted

    New buildings in Washington County.

    • The county states that the International Building Code and International Fire Code apply as amended by the state.
    “Washington County has adopted the International Building Code and the International Fire Code as amended by the state. All new buildings must meet applicable standards.”
  • InspectionsRequired

    Building work requiring the Washington County building permit package.

    • Final inspections are required.
    • Plumbing, mechanical, and electrical permits and inspections are the applicant’s responsibility.
    • The building official may enter property at reasonable times when necessary to enforce the code or when there is reasonable cause to believe a violation exists; occupied premises require credentials and requested entry, while unoccupied premises require reasonable efforts to locate the owner or person in control.
    “FINAL INSPECTIONS ARE REQUIRED. Plumbing, mechanical and electrical permits and inspections are your responsibility.”
  • Certificate of occupancyRequired

    Building projects covered by the county building permit package.

    • The requirement is stated pursuant to the applicable building code.
    “CERTIFICATE OF OCCUPANCY IS REQUIRED PURSUANT TO BUILDING CODE.”
  • County-wide zoningPresent (with conditions)

    Washington County zoning and land-use matters.

    • The county Planning and Zoning Commission conducts hearings on land-use and zoning matters.
    • Specific district standards and approvals were not fully extracted from the linked code book.
    “The Washington County Planning and Zoning Commission is required by state law to hold hearings on a variety of land use and zoning matters.”
    One more reviewed finding on this topic
    • Present — County zoning administration and zoning materials in Washington County.
      “View the Washington County Idaho Code Book. View the Idaho State Building Codes. [...] Zoning Map Link”
  • Local zoningPresent

    County-administered zoning in Washington County; this claim does not aggregate incorporated municipalities or other local ordinances.

    • The county Planning and Zoning Commission handles rezones, variances, special-use permits, development agreements, ordinance changes, and subdivisions.
    “The Washington County Planning and Zoning Commission is required by state law to hold hearings on a variety of land use and zoning matters.”
  • Zoning districtsPublished

    County zoning districts and zoning materials published through Washington County's Planning & Zoning resources.

    • District-specific dimensional and use rules were not separately extracted in this run.
    “A1 Agricultural: no color A2 Agricultural transitional: red C1 Commercial: yellow C2 Commercial: orange D1 Light industrial: light brown D2 Heavy industrial: dark brown R Recreation: blue”
  • Minimum dwelling sizeSpecified

    Manufactured homes used as dwellings under Washington County zoning definitions.

    • The manufactured home must be constructed according to HUD/FHA manufactured/mobile home construction and safety standards and built after July 1, 1976.
    • The definition describes a manufactured home as at least 600 square feet when erected on site, or at least 14 body feet wide or 40 body feet long in traveling mode.
    • A structure that meets all other requirements but not the size requirements may still qualify if the manufacturer voluntarily files the required HUD certification and complies with 42 USC section 5401 et seq.
    • This is a manufactured-home definition, not a confirmed minimum floor-area rule for every dwelling type.
    • County building permits remain required for construction, moving, or occupancy changes under Washington County Code § 3-1-3.

    minimum erected-on-site area: >= 600 square feet (The definition contains a HUD-certification exception for structures not meeting the size requirements.) · minimum traveling-mode width: >= 14 body feet (The definition also permits the 40-body-foot length criterion.) · minimum traveling-mode length: >= 40 body feet (The definition also permits the 14-body-foot width criterion.)

    “or when erected on site, is six hundred (600) or more square feet”
  • Minimum lot sizeDistrict specific (with conditions)

    Manufactured/mobile home park sites.

    • Manufactured/mobile home parks require a special use permit.
    • Each manufactured/mobile home site must have at least 4,500 square feet and minimum width of 45 feet.

    minimum lot size: >= 4500 square feet (Manufactured/mobile home park site) · minimum site width: >= 45 feet (Manufactured/mobile home park site)

    “four thousand five hundred (4,500) square feet”
  • SetbacksSpecified

    Buildings and structures in county zoning districts.

    • A1/A2: 15 feet from property boundary and street right-of-way, and 100 feet from state or federal highways, subject to stated exceptions.
    • C1/C2/D1/D2: 5 feet from property boundary, 40 feet from street right-of-way, and 100 feet from state or federal highways; if adjoining A1/A2, 15 feet from property line and 40 feet from county road.
    • Frontage requirements vary by zone.
    “In zones A1 and A2, no dwelling or structure or any portion thereof, except steps and uncovered porches less than ten feet (10') in width, shall be erected within fifteen feet (15') of the property boundary lines or within fifteen feet (15') of the street right of way or within one hundred feet (100') of any state or federal highway.”
  • Lot coverageSpecified

    Manufactured/mobile home park sites.

    • The limitation applies to manufactured/mobile homes and accessory structures on the manufactured/mobile home site.

    maximum lot coverage: <= 75 percent (Manufactured/mobile home park site)

    “The manufactured/mobile home and accessory structures shall not cover more than seventy five percent (75%) of the area of the manufactured/mobile home site.”
  • Building heightSpecified

    Buildings and structures in Washington County zoning districts A1, A2, C1, C2, D1, and D2.

    • Towers and similar structures may be exempted by special permits from the commission.

    maximum height in A1/A2/C1: <= 35 feet (Special permits may exempt towers and similar structures) · maximum height in C2: <= 45 feet (Special permits may exempt towers and similar structures) · maximum height in D1/D2: <= 100 feet (Special permits may exempt towers and similar structures)

    “towers and similar structures may be exempted”
  • Living in an RVLimited

    Transient recreational-vehicle sites in manufactured/mobile home parks.

    • Transient spaces may not exceed ten percent of manufactured/mobile home sites.
    • Transient recreational vehicles may stay no more than three months.
    • The site, yard, and property-development standards apply.

    maximum transient RV sites: <= 10 percent of manufactured/mobile home sites · maximum stay: <= 3 months

    “Transient spaces not more than ten percent (10%) of the manufactured/mobile home sites may be used for transient recreational vehicle sites. Sites reserved for transient recreational vehicles shall be so designated on the plans submitted with the application for the manufactured/mobile home park permit. The site, yard, and property development standards of this title shall fully apply to sites reserved for transient recreational vehicles. Such vehicles shall stay not more than three (3) months.”
  • Manufactured homesLimited

    Manufactured/mobile homes used as residences in Washington County.

    • The home must comply with county and state building, electrical, and plumbing codes.
    • A building inspector must issue a certificate of occupancy before occupancy.
    • A permanent foundation is not required for manufactured homes placed in mobile-home parks.
    • Permanent residences must be on a legal lot and meet placement requirements.
    “No mobile home may be occupied until the building inspector has issued a certificate of occupancy.”
  • Who permits septicLocal (with conditions)

    Septic and land-development permitting administered by Southwest District Health in its service area, including Washington County.

    • SWDH coordinates with the Idaho Department of Environmental Quality for sanitary restrictions and project reviews.
    • For subdivisions using individual wells and individual subsurface sewage disposal systems, SWDH requires a Subdivision Engineering Report before sanitary restrictions can be released.
    “Subdivisions that utilize individual wells and individual subsurface sewage disposal systems must complete a Subdivision Engineering Report (SER) through SWDH before sanitary restrictions can be released, the SER must be prepared by a Licensed Civil Engineer.”
  • Septic inspectionLimited

    Extended Treatment Package septic systems in Washington County.

    • ETP systems must undergo annual testing, inspection, and maintenance.
    • The work must be completed by a licensed service provider.

    inspection frequency: per 1 year (Applies to Extended Treatment Package systems.)

    “ETP systems are required to undergo annual testing, inspection, and maintenance to ensure proper operation.”
  • Mandatory utility hookupWater and sewer (with conditions)

    Manufactured/mobile home park sites.

    • Each manufactured/mobile home site must be served with water, electricity, and sanitary facilities.
    • Water and sewer distribution facilities must comply with Idaho Code and state and local regulations.
    “water, electricity and sanitary facilities”
  • Agricultural exemptionConditional

    Land used exclusively for agricultural purposes and qualifying farm or ranch buildings.

    • The zoning title does not apply to concrete ditches, pipelines, fences, wells, or similar improvements where land is used exclusively for agricultural purposes.
    • Farm and ranch buildings remain subject to 15-foot property-boundary and county-road setbacks and 40-foot public-road or street-right-of-way setbacks, with the code's stated exceptions.
    “land is used exclusively for agricultural purposes”
  • Subdividing landRegulated (with conditions)

    Subdivision and related zoning applications in Washington County.

    • Subdivision is processed through the Planning and Zoning Office.
    • Applications must be completed, accepted, and accompanied by fees before legal notice can be posted.
    • The hearing process requires legal notice at least three weeks before the hearing date.
    “To bring a zoning issue before the Planning and Zoning Commission, whether a Rezone, Variance, Special Use, Development Agreement, Ordinance Change, or Subdivision, you must contact the Planning and Zoning Office.”
    One more reviewed finding on this topic
    • Regulated (with conditions) — Subdivision activity in Washington County.
      “Subdivision regulations are found in Washington County’s Subdivision Ordinance. The ordinance provisions apply to all subdivision activity.”
  • Driveway accessRequired

    A residential dwelling requiring a building permit and a driveway approach onto a county road.

    • County road-supervisor approval of culvert installation and driveway approach must occur before and as a condition of obtaining the building permit.
    “The Washington County road supervisor must approve the culvert installation and the construction of the driveway approach onto a county road, prior to, and as a condition of, obtaining a building permit for a residential dwelling from the county.”
    One more reviewed finding on this topic
    • Required — Residential dwelling building permits in Washington County.
      “road supervisor must approve the culvert installation and the construction of the driveway approach onto a county road”
  • Building in a floodplainLimited

    Subdivision development within a floodway or floodway fringe in Washington County.

    • The subdivision checklist requires the general location of planned improvements, present water channel, planned rerouting, flood-proofing method, and means of insuring improvements in flood-prone areas.
    • The source does not establish a blanket countywide floodplain prohibition.
    “For developments within a floodway or flood way fringe (using the Army Corps of Engineers standards.) the sub divider shall submit the general location of all planned improvements, location of the present water channel, planned rerouting of waterways, method of flood proofing buildings and means of insuring improvements within the flood prone areas.”
  • Permit feesVariable (with conditions)

    County subdivision and related land-use development applications.

    • The official subdivision guide states that the applicant must pay a subdivision application fee and any other land-use development fees such as zone-change or special-use-permit fees.
    • No amount was established from the opened official source.
    “The applicant will pay a fee for the subdivision application along with any other land use development fees such as a zone change, special use permit.”
  • Permit processPublished (with conditions)

    Planning and Zoning applications for rezones, variances, special uses, development agreements, ordinance changes, and subdivisions.

    • Application must be completed and accepted by the Administrator.
    • Fees must be paid in time for legal notice to be posted at least three weeks before the hearing.
    • Applicants are advised to start at least four weeks before the hearing date.
    • Regular meetings are held the third Tuesday of each month at 6:00 p.m.

    legal notice lead time: >= 3 weeks · recommended preparation lead time: >= 4 weeks

    “To be on the agenda for a meeting you must have your application completed, accepted by the Administrator, and fees paid in time for the legal to be posted for at least 3 weeks prior to the hearing date.”
    One more reviewed finding on this topic
    • Partial — County subdivision and land-development approval process.
      “If a property is subject to subdivision regulation—the applicant must adhere to the following three-part public approval process: Phase 1: Pre-application Meeting Phase 2: Preliminary Plat Phase 3: Final Plat”

Idaho rules that apply here

  • Owner-builder exemptionConditional

    Homeowners personally performing plumbing work on their own residential premises in Idaho.

    • The homeowner must own the residential property and personally perform the permitted work.
    • The homeowner permit is valid only for a primary or secondary residence and associated outbuildings.
    • Associated outbuildings must not be used for commercial purposes or rented by a tenant.
    • The homeowner must accept responsibility for all work performed.
    • All work must be inspected by the Division of Occupational and Professional Licensing.
    • A plumbing permit must be obtained by application to the Division.
    • The application must be submitted with payment.
    • The application form states that an additional $65 fee may be assessed if the location is not clearly provided by directions or an attached map.
    • The application was revised 8/17/2022; this revision date is not treated as an effective date.

    unclear-location fee: 65 USD (May be assessed if the location is not clearly given by directions or an attached map.)

    “I certify that I am the owner of the residential property and will personally perform the work covered by this permit.”
    5 more reviewed findings on this topic
    • Available (with conditions) — An owner performing construction work on the owner's own land in Washington County, Idaho, for purposes of Idaho contractor-registration requirements.
      “Owners: Owners who do their own work on their own land and do not intend to sell the property within 12 months are exempt from registration.”
    • Available — An owner performing their own construction work on the owner's own land in Idaho.
      “A: Any person who engages in a construction job with a dollar amount exceeding $2000.00 (materials & labor) and is not otherwise exempt (The exemptions are listed below); [...] Owners: Owners who do their own work on their own land and do not intend to sell the property within 12 months are exempt from registration.”
    • Conditional — An Idaho homeowner undertaking construction or trade work for which a state-administered permit process applies.
      “Public (Homeowners Only) [...] *Public: “Homeowner” is pre-selected. [...] Once payment is processed, you may choose “Request Inspection” and/or “Print Permit””
    • Conditional — Owners performing construction work on their own land in Idaho under the state contractor-registration system.
      “Owners who do their own work on their own land and do not intend to sell the property within 12 months are exempt from registration.”
    • Conditional — Homeowners personally performing electrical work on a primary or secondary residence and related outbuildings in Idaho.
      “Homeowners may purchase a permit only when they themselves are doing electrical work on their primary or secondary residence and/or related outbuildings.”
  • Camping on your landLimited

    Camping or parking a vehicle or trailer on Idaho Fish and Game Wildlife Management Areas and access sites separate from a WMA.

    • The restriction applies in areas posted against camping or parking.
    • Leaving an unattended camp, vehicle, or trailer for more than 48 hours is prohibited without authorization.
    • Camping or parking for more than 10 days during any 30-day period on one WMA or one separate access site is prohibited without authorization.
    • The rule permits authorization by the Commission, Director, Regional Supervisor, or designee.

    unattended duration: > 48 hours (Unless specifically authorized by the Commission, Director, Regional Supervisor, or designee.) · camping or parking duration: > 10 days during any 30-day period per WMA or separate access site (Unless specifically authorized by the Commission, Director, Regional Supervisor, or designee.)

    “camp or park a vehicle or trailer for more than ten (10) days during any thirty (30) day period”
  • Accessory dwellingsLimited

    Accessory dwelling units for Idaho DEQ wastewater-flow and septic-system sizing purposes; this claim does not establish statewide zoning permission.

    • An ADU is sized as a single-family dwelling for the cited wastewater-flow guidance.
    • An ADU may combine flows with another structure into one system.
    • Any common septic tank must be large enough to hold the required capacity from both structures.
    • Local land-use, building, and septic authorities may impose additional requirements.

    wastewater flow basis: single-family dwelling

    “Size as a single family dwelling. Can combine with another structure's flows into one system”
  • Septic permitRequired

    Modification, repair, expansion, or installation of an individual or subsurface sewage disposal system anywhere in Idaho.

    • A valid installation permit is required unless an exception in IDAPA 58.01.03 Section 005.02 applies.
    • Portable nondischarging systems may be installed as temporary blackwaste or wastewater systems if properly maintained and of a design approved by the Director.
    • Individual and subsurface disposal systems may be repaired without a valid installation permit when needed because of clogged or broken solid piping or malfunctions in an electrical or mechanical system; the repair may not expand the system unless authorized by the Director.
    • Unless otherwise stated on the application or permit, authorized construction or activity must be completed and approved within two years after issuance or the permit becomes invalid.
    • At the Director’s discretion, a permit may be renewed if the request is received before the permit’s expiration date.
    • Construction must comply with the approved plans, specifications, and conditions; deviations require advance Director approval.
    • Idaho’s public health districts administer the state rules under an MOU with the Idaho Department of Environmental Quality and issue septic system permits.
    • A local zoning, building, fire, safety, or health regulation establishing a higher protective standard prevails when the state rule conflicts with it.

    permit validity period: 2 years (Unless otherwise stated on the application or permit; authorized construction or activity must be completed and approved within this period.)

    “Except as specified in Subsection 005.02 no person may modify, repair or expand or install any individual or subsurface sewage disposal system within the state of Idaho unless there is a valid installation permit authorizing that activity.”
    2 more reviewed findings on this topic
    • Required — Installation, modification, repair, or expansion of an individual or subsurface sewage disposal system in Washington County under Idaho state rules.
      “Except as specified in Subsection 005.02 no person may modify, repair or expand or install any individual or subsurface sewage disposal system within the state of Idaho unless there is a valid installation permit authorizing that activity.”
    • Required — Installation of individual or subsurface sewage disposal systems in Washington County.
      “To have a septic system installed, the property owner must obtain a permit from a public health district.”
  • Well permitRequired

    Construction or drilling of wells in Idaho, including domestic wells.

    • Before drilling, the well owner or driller must obtain a drilling permit from IDWR.
    • All wells must be constructed by a well driller with a valid IDWR license.
    • The separate water-right permit exemption for domestic purposes does not eliminate the drilling-permit requirement.
    • For new diversions in qualifying subdivisions filed on or after July 1, 2025, a water-right permit is required in a moratorium area, critical groundwater area, or groundwater management area, except for in-home uses and watering livestock.
    • Well construction rules apply to wells and other artificial openings more than 18 vertical feet below land surface.

    well depth threshold: > 18 vertical feet below land surface (The cited well-construction rules describe covered wells and artificial openings.) · subdivision application date: >= 2025-07-01 (Applies to qualifying new diversions described in Idaho Code § 42-227(4).)

    “Prior to drilling a well, the well owner or well driller must first obtain a drilling permit from IDWR.”
    One more reviewed finding on this topic
    • Required — Drilling a well in Washington County.
      “Idaho law requires all well drillers to be licensed and obtain a permit before drilling.”
  • Campground & park staysLimited

    Temporary camping in Idaho State Parks administered by the Idaho Department of Parks and Recreation.

    • Camping is permitted only in designated areas.
    • Stays are limited to 14 nights in a 30-day period; the same page's FAQ separately states a 15-day limit, creating an unresolved internal discrepancy.
    • Individual-site occupancy is limited to one family unit or no more than 8 persons unless otherwise specified; companion-site and site-design restrictions apply.
    • Camping is not permitted on beaches, parking lots, or day-use facilities.
    • Check-in is at 2 p.m. for campsites and checkout is at 1 p.m.; late checkouts may incur additional fees unless prior arrangements have been made.

    state-park stay limit: 14 nights in 30 days (FAQ on the same page states 15 days in any 30-day period) · individual-site people limit: <= 8 people (one family unit or site-specific limits may apply)

    “Camping is permitted only in designated areas. [...] Stays are limited to 14 nights in a 30-day period.”
  • county zoning authorityGeneral

    Idaho counties adopting zoning for unincorporated areas through their boards of county commissioners.

    • A board of county commissioners is a governing board and may exercise the powers authorized by the Local Land Use Planning Act.
    • The county board's powers under the chapter apply to the unincorporated area of the county.
    • Zoning must be adopted, amended, or repealed by ordinance using the notice and hearing procedures in Idaho Code § 67-6509.
    • Zoning districts must conform to the adopted comprehensive plan.
    • Within zoning districts, standards may regulate or restrict building height, number of stories, size, construction, reconstruction, alteration, repair or use of buildings and structures; lot occupancy; courts, yards and open spaces; population density; and building and structure location and use.
    • Standards must be uniform for each class or kind of building throughout each district, but may differ between districts.
    • Overlay zoning districts require clear and objective standards and must not constitute a regulatory taking under Idaho or federal law.
    “The powers of the board of county commissioners conferred by this chapter shall apply to the unincorporated area of the county.”
  • county building authorityGeneral

    Idaho counties' authority to adopt and enforce building codes and require permits for residential construction in unincorporated areas when the county operates a building-code enforcement program.

    • The statute defines local government as any city or county of Idaho.
    • A local government that had not previously implemented a code-enforcement program may elect to implement one by ordinance evidencing its intent to do so.
    • Construction in a local-government jurisdiction enforcing building codes requires a permit under the applicable local ordinance.
    • A local government issuing permits and performing enforcement must adopt the specified state-adopted codes and may amend them only within the limits stated in Idaho Code § 39-4116(4).
    • Local amendments must generally provide at least an equivalent level of protection; accessibility amendments are restricted, and additional residential-code amendments require the statutory good-cause, necessity, ordinance, public-hearing, publication, and notice procedures.
    • Single-family homes and multiple-family dwellings up to two units are exempt from automatic fire-sprinkler requirements in the enumerated codes.
    • Agricultural buildings must be exempted; a county may issue farm-building permits only for road setbacks and utility easements, at no more than actual issuance cost.
    • Permits are governed by the laws in effect when the application is received.
    • The state division retains jurisdiction for in-plant inspections and installation standards for manufactured or mobile homes and for in-plant inspections and enforcement of modular-building and commercial-coach construction standards.
    “"Local government" means any city or county of this state.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

  • Tiny homes — Tiny-home occupancy on private land in unincorporated Washington County.
  • Off-grid sanitation — Off-grid sanitation systems in Washington County.
  • Short-term rentals — Short-term rental use in unincorporated Washington County.

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Living off-grid in Washington County, Idaho

Is Washington County a good place to live off-grid or homestead?

Washington County scores 63/100 on the Bolthole Index, a solid county profile. Its strengths: a stronger property-autonomy legal backdrop and sparse surroundings — about 918 people within a 30-minute drive. Watch-outs: more administrative friction around building and land use.

Do you need a building permit in Washington County, Idaho?

Washington County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Southwest District Health. Owner-builders may act as their own contractor to build their home. These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

How much does land cost in Washington County, Idaho?

Land in Washington County runs about $2,299 per acre, based on the latest county data.

What is the water situation in Washington County?

Washington County gets about 20.7" of rain a year, with severe drought in roughly 16.2% of years.

How remote is Washington County?

A representative private-land location has about 918 people within a 30-minute drive and 791,077 within two hours. The road-network catchments count population across county lines and clusters of smaller cities; straight-line radius values remain available as a comparison.

How Washington compares in Idaho

Compare side-by-side →See all 44 Idaho counties ranked →