Bolthole Index

Wahkiakum County, Washington

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

67Index Score / 100
#3 of 39 in Washington

Wahkiakum County, Washington requires a building permit for houses, tiny houses, pole barns, sheds, and anything converted to a permanent residence1. Building & Planning handles applications in unincorporated Wahkiakum County, while a structure inside Cathlamet needs a building permit from the town clerk23. Unincorporated land has no zoning, but Cathlamet has its own zoning; county Health & Human Services handles septic installation permits456.

At a glance

Building permit
Required for permanent residences and attached structures; not required for detached, recreational structures without plumbing or conditioned air17
Zoning
None in unincorporated Wahkiakum County; only the incorporated Town of Cathlamet has adopted zoning under its Title 19845
Septic
Wahkiakum County Health & Human Services issues septic installation permits for new construction and repairs, backed by a licensed designer's or engineer's design6910
Owner-builder
Yes: an owner working on their own property is exempt from contractor registration, but a building permit is still required1112
Utility hookup before permit
A permanent residence needs potable water and Environmental Health-approved sewer or septic before the building permit will be accepted13
RV living
Permanent-residence use requires the RV's own potable water and sewer or septic; temporary camping remains unconfirmed14
Tiny homes
A county building permit is required when used as a permanent residence, with plumbing, conditioned air, potable water, and approved sewer or septic15
Minimum lot size
1 acre with a well and septic; 1/2 acre with public water and septic16

Who to call

Building permits

Wahkiakum County Building & Planning Department

Building permits, land use, shoreline (JARPA/SEPA) permits, and manufactured-home placement for unincorporated Wahkiakum County

360-795-6100

hicksd@wahkiakumcounty.gov

64 Main Street, Cathlamet, WA 98612

Septic permits

Wahkiakum County Health & Human Services - Environmental Health

On-site septic system (OSS) installation permits, test pits, and site/soil evaluations for new construction, repairs, and land divisions in Wahkiakum County

42 Elochoman Valley Road, Cathlamet, WA 98612

Roads & driveways

Wahkiakum County Public Works Department (County Road Approach permits)

County Road Approach permit applications for driveways that intersect a county road

tobinj@wahkiakumcounty.gov

Contact details are copied from each office’s official page and were checked against it on October 7, 2026.

Off-grid gear

Going off-grid in Wahkiakum 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 Wahkiakum County, Washington?

Yes, for most construction. The Wahkiakum County Building Permit Application Packet is required for houses, tiny houses, pole barns, sheds, or any other structure converted to a permanent residence7. A permanent residence must have plumbing, conditioned air, potable water, and Environmental Health-approved sewer or septic before you can apply113. A detached structure used only recreationally, without plumbing or conditioned air, does not need a building-permit application and cannot be used as a permanent residence7. Work in unincorporated Wahkiakum County that changes a structure's occupancy classification requires a building permit and inspection17. Wahkiakum County enforces the 2021 International Building, Residential, Mechanical and Fire Codes, the 2021 Uniform Plumbing Code, and the 2021 Washington State Energy Code with Washington amendments18. Washington's owner-builder exemption permits owners to work on their own property without contractor registration, but building permits still apply and the exemption does not cover work for sale, demolition, or lease1112. Qualifying work tied to farming, dairying, agriculture, horticulture, livestock or poultry also has a contractor-registration exemption, but that exemption does not waive Wahkiakum County building permits197.

Who issues building permits in Wahkiakum County, and how do you apply?

For unincorporated land, Wahkiakum County's Building & Planning Department is at 64 Main Street, Cathlamet, WA 98612; reach the building inspector at hicksd@wahkiakumcounty.gov, office line 360-795-6100 extension 104, or work cell 360-353-807420. Call ahead to confirm the required documents; applications and building documents may be emailed, and the county will not process an incomplete submission2. Inside the incorporated Town of Cathlamet, obtain the building permit from the town clerk before erecting a building3. County building permit fees are published: a new residence between 120 and 1,000 square feet runs $506.50, and one between 1,001 and 2,000 square feet runs $606.50, with the schedule's additional $4.50 building-permit fee21. A flood-elevation certificate, SEPA application, or JARPA application may also be required depending on the unincorporated property's location2. If a driveway intersects a county road, Public Works handles the separate County Road Approach permit application at tobinj@wahkiakumcounty.gov2223.

Does Wahkiakum County have zoning?

No. Cathlamet is the only incorporated town inside Wahkiakum County, and the rest of the county is unincorporated and has no county zoning districts424. The Town of Cathlamet has its own Title 19 zoning, so land inside town limits is governed differently5. Because unincorporated Wahkiakum County has no zoning ordinance, county zoning does not restrict accessory dwellings or temporary camping there; building-code, septic, shoreline, floodplain and other non-zoning rules can still apply25. Unincorporated Wahkiakum County has no minimum dwelling size, lot-coverage limit, or building-height limit imposed solely through county zoning262728. House setbacks are 30 feet from mean high water, 5 feet from a side lot line, and 15 feet from a road right-of-way line; some reductions may be available through a variance or the responsible department29. Residential lots need at least 1 acre with a well and septic or 1/2 acre with public water and septic16. Land division also requires county approval under the applicable short-plat or subdivision process30.

How do septic permits work in Wahkiakum County?

Wahkiakum County Health and Human Services issues septic installation permits for new construction and repairs9. Every application must include two copies of a septic-system design prepared by a licensed on-site wastewater treatment system designer or professional engineer10. The county requires test pits so the county and designer can evaluate the soil and choose the system type31. The local health officer must inspect permitted on-site sewage work, and the system must be inspected before cover; ongoing inspections are at least every 3 years for a sewage tank with a gravity soil dispersal component and annually for other systems unless the health officer requires more frequent checks32. A permanent residence cannot obtain a building permit until Environmental Health approves sewer or septic and potable water is confirmed33. Only 6.8% of Wahkiakum County soils have no severe limitation for a conventional drain field, so complete the site and soil evaluation before committing to a house location34. Environmental Health is at 42 Elochoman Valley Road, Cathlamet, WA 9861231.

Can you live in an RV or tiny home on your land in Wahkiakum County?

Unincorporated Wahkiakum County has no county zoning restriction on temporary camping, but an RV used as a permanent residence must have its own potable water and sewer or septic2514. A tiny house used as a permanent residence requires the county building-permit packet plus plumbing, conditioned air, potable water, and approved sewer or septic15. Washington defines a code-built tiny house as no more than 400 square feet, including its kitchen, bathroom, and sleeping area35. Unincorporated Wahkiakum County adds no minimum dwelling size solely through zoning, although the building code and other site rules still apply26. A manufactured home needs a county placement permit, foundation specifications, engineered anchoring, approved septic and water, and a title-elimination permit; the title-elimination requirement also applies inside Cathlamet36.

Building a home in Wahkiakum County: the steps, in order

  1. Confirm whether the parcel is inside Cathlamet: the town clerk issues building permits in town, while county Building & Planning handles unincorporated projects32.
  2. For unincorporated land, check that the lot and house location can meet the applicable minimum lot size and setbacks before finalizing plans1629.
  3. Start the septic site and soil evaluation with Wahkiakum County Health & Human Services; test pits come before system design31.
  4. Have a licensed designer or professional engineer prepare the septic design, then secure Environmental Health approval and confirm potable water1013.
  5. Call county Building & Planning before submitting an unincorporated application, confirm every required document, and email the application and building documents if convenient; incomplete applications are not processed2.
  6. Obtain a County Road Approach permit through Public Works if the driveway intersects a county road2223.
  7. Ask whether the property's location also requires a Flood Elevation Certificate, SEPA application, or JARPA application2.

What to check before you buy land in Wahkiakum County

Check the soil before you assume a standard septic system will work: only 6.8% of Wahkiakum County's soils carry no severe limitation for a conventional drain field, so a site and soil evaluation matters before you commit34. Confirm the parcel is outside Cathlamet if you're counting on no zoning review; land inside the town is governed by Title 19 zoning instead45. If the tract you're buying was recently split from a larger parcel, ask whether it went through the county's short-plat or subdivision process, which applies to any division into four or more parcels where the smallest lot is under five acres30. Terrain here is steep by rural standards: only 28.2% of the county sits at 15% slope or less, while 85.1% is forested, so grading and access can matter as much as soils3738. Rainfall is heavy, at about 81.7 inches a year, with severe drought in only 4.8% of years, which favors a well but means drainage and site grading deserve real attention3940. If your driveway will connect to a state highway rather than a county road, you need written permission from the Washington Department of Transportation before building it, separate from the county's Road Approach permit41. Budget for carrying costs too: the effective property tax rate runs about 0.6%, with a median annual bill near $2,084, against a typical home value around $405,190424344.

Watch-outs

  • Only the incorporated Town of Cathlamet has zoning in Wahkiakum County; the rest of the county is unincorporated with no zoning, but that means building and land-use rules still run through Building & Planning, not that anything goes420.
  • A detached recreational structure or RV without its own plumbing and conditioned air avoids a building permit, but Wahkiakum County's own rule is explicit that it cannot legally be used as a permanent residence7.
  • If your land is in a mapped flood area, the county requires a Flood Elevation Certificate before it will issue a building permit at all; confirm this early rather than after you've designed your home45.

Sources

  1. Land Use, Building Permits & Shoreline Permits (2026 county census)
  2. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  3. 18.65.010 Required | Cathlamet Municipal Code, quoted and re-checked
  4. FAQs • Is there zoning in Wahkiakum County?, quoted and re-checked
  5. FAQs • Is there zoning in Wahkiakum County?, quoted and re-checked
  6. On-Site Septic System Permits (2026 county census)
  7. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  8. FAQs • Is there zoning in Wahkiakum County? (2026 county census)
  9. On-Site Septic System Permits, quoted and re-checked
  10. On-Site Septic System Permits, quoted and re-checked
  11. Washington State Legislature - RCW 18.27.090 Exemptions (2026 county census)
  12. RCW 18.27.090: Exemptions, quoted and re-checked
  13. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  14. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  15. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  16. co.wahkiakum.wa.us, quoted and re-checked
  17. Title 30 Building Codes and Permits, quoted and re-checked
  18. 2024 Wahkiakum County Building Code Requirements, quoted and re-checked
  19. RCW 18.27.090: Exemptions, quoted and re-checked
  20. Wahkiakum County Building & Planning Department (co.wahkiakum.wa.us)
  21. Wahkiakum County Building Section Permit Fee Schedule, quoted and re-checked
  22. Wahkiakum County Public Works Department (County Road Approach permits) (co.wahkiakum.wa.us)
  23. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  24. Building & Planning FAQs, quoted and re-checked
  25. Washington law on county zoning and building authority
  26. Building & Planning FAQs, quoted and re-checked
  27. Building & Planning FAQs, quoted and re-checked
  28. Building & Planning FAQs, quoted and re-checked
  29. Setback Requirements for Residential Developments, quoted and re-checked
  30. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  31. Wahkiakum County Health & Human Services - Environmental Health (co.wahkiakum.wa.us)
  32. WAC 246-272A-0260 Inspection, quoted and re-checked
  33. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  34. 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
  35. Tiny Houses (Washington statewide rule), quoted and re-checked
  36. Land Use, Building Permits & Shoreline Permits, quoted and re-checked
  37. Share of land at 15% slope or less: Bolthole Index county data
  38. Wooded share of land: Bolthole Index county data
  39. Annual precipitation: Bolthole Index county data
  40. Share of years in severe drought: Bolthole Index county data
  41. RCW 47.32.150 — Approach roads, other appurtenances—Permit (Washington statewide rule), quoted and re-checked
  42. Effective property tax rate: Bolthole Index county data
  43. Median property tax bill: Bolthole Index county data
  44. Typical home value (Zillow): Bolthole Index county data
  45. Wahkiakum County Building Permit Process, quoted and re-checked

Written October 7, 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

Unlike all 6 of its neighbors, Wahkiakum County has no countywide zoning.

RuleWahkiakum CountyPacific CountyCowlitz CountyLewis CountyClark CountyThurston CountyGrays Harbor County
Building permitRequiredRequiredRequiredRequiredRequiredRequiredRequired
County zoningNoYesYesYesYesYesYes
Septic permitsCounty Health & Human ServicesCounty Env. Health Div.County Health Dept.County Env. HealthCounty Public HealthCounty Public Health & Social ServicesCounty Env. Health Div.

County locator

Wahkiakum County in Washington

67
County map
Wahkiakum County highlighted among the Washington counties · colored by Index score

How Wahkiakum County scores

Seclusion54100% ev.
Self-Sufficiency62100% ev.
Admin Boringness58100% ev.
Durability53100% ev.
Property Autonomy50100% ev.
Carry Cost70100% ev.

Evidence strength: 100%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$405kTypical home
0.6%Property tax
$6,630Land / acre
81.7"Annual rain
4.8% of yrsSevere drought
0.2 / yr (+0.2)Mid-century 100°F days
17.4 daysMid-century dry spell
2.91" (+7.5%)Mid-century 1-day rain
1.32×Wildfire change factor
100%Forward climate coverage
$1,526Home insurance / yr
1.2% / yrInsurance growth
0%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
19,767Radius comparison (15 mi)
18.1People / sq mi
1.8%Federal land
28.2%Land at 15% slope or less
6.8%Soils rated "not limited" for septic (strict USDA rating)
11,112 acWorkable land screen
85.1%Wooded land
96.6 tonsBiomass / forest ac
50.5°FAvg temp

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Cities and towns in Wahkiakum 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.

Answers from the rulebook for Wahkiakum County

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

Wahkiakum County rules

  • Building permitRequired

    Houses, tiny houses, pole barns, sheds, and other structures converted to permanent residences.

    • Recreational detached structures without plumbing or conditioned air do not require this application and cannot be permanent residences.
    • Permanent residences require plumbing, conditioned air, potable water, and County Environmental Health-approved sewer or septic before application.
    “The Wahkiakum County Building Permit Application Packet is required for: houses, tiny houses, pole barns, sheds, or any other structure that will be converted to a permanent residence.”
  • Building code adoptedAdopted (with conditions)

    Building work administered by the Wahkiakum County Building and Planning Department.

    • County document lists Washington State Amendments to the listed codes.

    code editions: 2021 International Building, Residential, Mechanical, and Fire Codes; 2021 Uniform Plumbing Code; 2021 Washington State Energy Code

    “Wahkiakum County Building Code Requirements Codes 2021 International Building Code 2021 International Residential Code 2021 International Mechanical Code 2021 International Fire Code 2021 Uniform Plumbing Code (IAMPO) 2021 Washington State Energy Code Washington State Amendments to the above codes”
  • InspectionsRequired

    Work in unincorporated Wahkiakum County that changes occupancy classification and therefore requires a building permit.

    • The quoted county code provision concerns changes in occupancy classification.
    • Incorporated cities or towns may have separate permit requirements.
    “any work regardless of its nature, that results in a change in occupancy classification shall require a building permit and shall be subject to inspection.”
  • County-wide zoningAbsent

    County zoning in unincorporated Wahkiakum County.

    • The incorporated Town of Cathlamet has zoning.
    “Cathlamet is the only incorporated town inside of Wahkiakum County. The rest of Wahkiakum County is unincorporated and does not have zoning.”
  • Local zoningVaries (with conditions)

    County aggregate of local zoning: incorporated Cathlamet and unincorporated county.

    • Cathlamet is the only incorporated town in the county and has zoning under its Title 19.
    • The rest of the county is unincorporated and has no zoning.
    “The incorporated Town of Cathlamet has zoning. Reference Title 19 Zoning Town of Cathlamet for more information.”
  • Zoning districtsNot published (with conditions)

    County zoning districts in unincorporated Wahkiakum County.

    • The county states that unincorporated areas have no zoning; therefore no county zoning-district schedule applies there.
    • Cathlamet, an incorporated town, may have separate municipal zoning rules.
    “There is no zoning in the unincorporated areas of Wahkiakum County.”
  • Minimum dwelling sizeNone (with conditions)

    Minimum dwelling size imposed solely through county zoning in unincorporated Wahkiakum County.

    • The no-zoning statement does not eliminate building-code, health, septic, floodplain, shoreline, or other non-zoning requirements.
    “There is no zoning in the unincorporated areas of Wahkiakum County.”
  • Minimum lot sizeSpecified

    Residential lot sizes in Wahkiakum County where the property uses a well and septic or septic with public water.

    • With a well and septic, the minimum lot size is one acre.
    • With septic and public water, the minimum lot size is one-half acre.

    minimum lot size with well and septic: 1 acre · minimum lot size with septic and public water: 0.5 acre

    “The minimum lot size is 1 acre if there will be a well and septic on the property. If there will be a septic and public water, minimum lot size is 1/2 acre.”
  • SetbacksSpecified

    Residential development setbacks in Wahkiakum County.

    • House setbacks are 30 feet from mean high water lines, 5 feet from side lot lines, and 15 feet from road right-of-way lines.
    • Septic drainfields are 100 feet from mean high water lines and septic tanks are 50 feet from mean high water lines.
    • Uncovered porches, decks, and steps have 10-foot, 5-foot, and 15-foot setbacks from the respective water, side-lot, and road references.
    • Garages and shops have 30-foot, 5-foot, and 15-foot setbacks.
    • Parking lots have a 50-foot setback from mean high water lines.
    • In some situations, distances may be reduced by a variance or by talking to the department requiring the setback.

    house setback from mean high water line: 30 feet (SMMP) · house setback from side lot line: 5 feet (WCBS) · house setback from road right-of-way line: 15 feet (WCPW) · septic drainfield setback from mean high water line: 100 feet (WHD) · septic tank setback from mean high water line: 50 feet (WHD)

    “HOUSE: Setbacks from property lines and water courses 30’ from mean high water lines (SMMP) 5’ from side lot lines (WCBS) 15’ from road r/w lines (WCPW)”
  • Lot coverageNone (with conditions)

    Lot-coverage limits imposed solely through county zoning in unincorporated Wahkiakum County.

    • The no-zoning statement does not eliminate building-code, shoreline, floodplain, critical-area, septic, or other non-zoning controls.
    “There is no zoning in the unincorporated areas of Wahkiakum County.”
  • Building heightNone (with conditions)

    Building-height limits imposed solely through county zoning in unincorporated Wahkiakum County.

    • The no-zoning statement does not eliminate building-code, shoreline, floodplain, critical-area, fire-code, or other non-zoning controls.
    “There is no zoning in the unincorporated areas of Wahkiakum County.”
  • Living in an RVLimited

    Recreational vehicles used as permanent residences in unincorporated Wahkiakum County.

    • Permanent-residence RV use requires its own potable water and sewer or septic.
    • The county page does not establish unrestricted RV occupancy or temporary camping rights.
    “Recreational vehicles that will be used as permanent residences require their own potable water and sewer/ septic.”
  • Camping on your land · by state lawUnrestricted

    Unincorporated Wahkiakum County: no county rule sets this, because Wahkiakum County's own reviewed answer confirms it has no county-wide zoning ordinance.

    • Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
    • The incorporated Town of Cathlamet has zoning.
    “Cathlamet is the only incorporated town inside of Wahkiakum County. The rest of Wahkiakum County is unincorporated and does not have zoning.”
  • Tiny homesLimited

    Tiny houses used as permanent residences in unincorporated Wahkiakum County.

    • A building permit application packet is required for tiny houses.
    • Permanent residences require plumbing, conditioned air, potable water, and approved sewer or septic before applying for a building permit.
    • The county page refers applicants to Washington Labor and Industries tiny-house information.
    “The Wahkiakum County Building Permit Application Packet is required for: houses, tiny houses, pole barns, sheds, or any other structure that will be converted to a permanent residence.”
  • Manufactured homesLimited

    Manufactured-home placement and occupancy in unincorporated Wahkiakum County.

    • A manufactured-home placement permit is required.
    • The application requires foundation specifications, an engineered anchoring system, and an approved septic and water source.
    • The county also requires a title-elimination permit throughout the county, including Cathlamet city limits.
    “The Wahkiakum County Manufactured Home Placement Permit Application is required for the placement of a manufactured home.”
  • Accessory dwellings · by state lawUnrestricted

    Unincorporated Wahkiakum County: no county rule sets this, because Wahkiakum County's own reviewed answer confirms it has no county-wide zoning ordinance.

    • Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
    • The incorporated Town of Cathlamet has zoning.
    “Cathlamet is the only incorporated town inside of Wahkiakum County. The rest of Wahkiakum County is unincorporated and does not have zoning.”
  • Who permits septicCounty (with conditions)

    On-site septic installation permits for new construction and repairs.

    • Applications must include two copies of a septic-system design by a licensed on-site wastewater-treatment-system designer or professional engineer.
    “Wahkiakum County Health and Human Services issues septic installation permits for new construction and repairs.”
  • Septic permitRequired

    New construction and repairs using on-site septic systems.

    • Application requires two design copies prepared by a licensed designer or professional engineer.
    “Septic installation permit applications must be accompanied by two copies of a septic system design prepared by a licensed on-site wastewater treatment system designer or professional engineer.”
  • Off-grid sanitationLimited

    Permanent residences using on-site sanitation instead of public sewer.

    • County Environmental Health must approve septic before the building-permit application.
    “Permanent residences require potable water and sewer or septic that is approved by Wahkiakum County Environmental Health Department prior to applying for a building permit.”
  • Mandatory utility hookupConditional

    Permanent residences applying for a county building permit.

    • A permanent residence requires potable water and County Environmental Health-approved sewer or septic before applying for a building permit.
    “Permanent residences require potable water and sewer or septic that is approved by Wahkiakum County Environmental Health Department prior to applying for a building permit.”
  • Subdividing landRegulated (with conditions)

    Land divisions in Wahkiakum County.

    • A short plat is a division into four or fewer parcels where the smallest lot is less than five acres.
    • A subdivision is a division into four or more parcels where the smallest lot is less than five acres.

    short plat maximum parcels: <= 4 parcels (smallest lot is less than 5 acres) · subdivision minimum parcels: >= 4 parcels (smallest lot is less than 5 acres)

    “A Short Plat is any division of land into 4 or fewer parcels where the smallest lot is less than 5 acres. A Subdivision is any division of land into 4 or more parcels where the smallest lot is less than 5 acres.”
  • Driveway accessRequired

    Driveways intersecting a county road.

    • The County Public Works Department handles the County Road Approach permit application.
    “The County Road Approach Application is required for driveways that intersect a county road. The Wahkiakum County Public Works Department handles the County Road Approach permit application.”
  • Building in a floodplainLimited

    Building-permit applicants in flood areas.

    • A Flood Elevation Certificate may be required for applicants living in a flood area.
    • The building permit will not issue without the required listed information.
    “If you live in a flood area you may need to submit a Flood Elevation Certificate. A building permit will not be issued without the above information.”
  • Permit feesPublished (with conditions)

    County Building Section permit fees.

    • The schedule identifies itself as Revision 9/2017.
    • A stated building permit fee of $4.50 is added to starred fees.

    new residence fee, 120 to 1,000 square feet: 506.5 USD (starred fee; schedule states $4.50 building-permit fee added) · new residence fee, 1,001 to 2,000 square feet: 606.5 USD (starred fee; schedule states $4.50 building-permit fee added)

    “Building- New Residence Residential 120 s.f. to 1,000 s.f. * $506.50 1,001 s.f. to 2,000 s.f. * $606.50”
  • Permit processPublished (with conditions)

    Building-permit application process for projects in unincorporated Wahkiakum County.

    • Applicants should call ahead and confirm that all necessary documents are ready.
    • Applications and building documentation may be submitted by email.
    • If required documents are missing, the application will not be processed.
    • The listed documents may not be complete, and not all documents are needed for every project.
    • Depending on property location, additional documents may be required, including a flood-elevation certificate, SEPA application, or JARPA application.
    • For building structures converted to permanent residences, the county requires the building permit application packet; permanent residences require plumbing, conditioned air, Washington State Energy Code compliance, and potable water plus county-approved sewer or septic before applying.
    • The county page states that incorporated Cathlamet has its own zoning and is separately scoped below.
    “When you are ready to submit your application for permits it is best to call ahead and confirm with our building inspector that you have all of the necessary documents ready to submit. You can submit your application and all necessary building documentation by email. If you show up to the office and are missing required documents then your application will not be processed.”

Washington rules that apply here

  • Owner-builder exemptionConditional

    An owner or other person performing construction-related contractor activities on the person's own property or personal residence under Washington contractor-registration law.

    • The exemption concerns registration provisions under chapter 18.27 RCW and does not itself eliminate applicable building, electrical, plumbing, mechanical, land-use, or inspection requirements.
    • For work on the person's own property, the exemption does not apply when the person performs contractor activities for the purpose of selling, demolishing, or leasing the property.
    • For an owner contracting with a registered contractor, the exemption does not apply to a person performing contractor activities to lease or sell improved property owned for less than twelve months.

    small-project contract threshold: < 500 USD (The threshold exemption does not apply when the work is part of a larger operation, contracts are divided to evade the chapter, or the person advertises as a contractor.)

    “The registration provisions of this chapter do not apply to: [...] (12) Any person working on his or her own property, whether occupied by him or her or not, and any person working on his or her personal residence, whether owned by him or her or not but this exemption shall not apply to any person who performs the activities of a contractor on his or her own property for the purpose of selling, demolishing, or leasing the property;”
    One more reviewed finding on this topic
    • Conditional — Washington contractor-registration requirements for a person working on their own property or personal residence, including in Wahkiakum County.
      “(12) Any person working on his or her own property, whether occupied by him or her or not, and any person working on his or her personal residence, whether owned by him or her or not but this exemption shall not apply to any person who performs the activities of a contractor on his or her own property for the purpose of selling, demolishing, or leasing the property;”
  • Septic inspectionRequired

    On-site sewage systems in Wahkiakum County under Washington statewide requirements.

    • For all activities requiring a permit, the local health officer must inspect the OSS.
    • The local health officer visits during site evaluation, construction, or final construction inspection.
    • The OSS must be inspected before cover, either by the local health officer or by the designer when the designer is not also the installer.
    • For ongoing maintenance, inspections are at least every three years for systems consisting solely of a sewage tank and gravity SSAS, and annually for all other OSS unless more frequent inspections are specified by the local health officer.
    • The state rule was effective April 1, 2025.

    inspection interval for sewage tank and gravity SSAS: 3 years (unless more frequent inspections are specified by the local health officer) · inspection interval for other OSS: 1 year (unless more frequent inspections are specified by the local health officer)

    “At least once every three years, unless more frequent inspections are specified by the local health officer, for all OSS consisting solely of a sewage tank and gravity SSAS;”
    One more reviewed finding on this topic
    • Required — On-site sewage systems for all activities requiring an OSS permit statewide.
      “(1) For all activities requiring a permit, the local health officer shall inspect the OSS.”
  • Well permitLimited

    Groundwater wells and groundwater uses statewide under Washington's water-right permit exemption.

    • Domestic use is exempt up to 5,000 gallons per day.
    • Industrial use is exempt up to 5,000 gallons per day.
    • Lawn or garden irrigation is exempt only for a half-acre or less.
    • Stockwater is exempt.
    • Only one permit-exempt use of each type is allowed for any one project, regardless of project size.
    • Withdrawals from multiple wells for one project are aggregated toward the exemption limits.
    • Local governments and other laws and rules may impose additional requirements and limits.
    • Use in excess of the listed amounts, use for other purposes, or use from a surface-water source requires applying for and receiving a water-right permit.
    • Before drilling, a notice of intent must be submitted to Ecology 72 hours before drilling starts; the NOI is not itself a permit or approval to use water.
    • Permit-exempt uses remain subject to state water law, including possible restrictions relating to senior water rights and Streamflow Restoration Act requirements.

    domestic groundwater use exemption: <= 5000 gallons per day (Per project, with withdrawals from multiple wells aggregated.) · industrial groundwater use exemption: <= 5000 gallons per day (Per project, with withdrawals from multiple wells aggregated.) · lawn or garden irrigation exemption: <= 0.5 acre (For lawn or garden irrigation.) · well construction notice: 72 hours before drilling (Notice of intent is not a permit, certificate, or water-right application.)

    “The groundwater permit exemption allows for four small uses of groundwater without a water right permit: Domestic uses of up to 5,000 gallons per day Industrial uses of up to 5,000 gallons per day Irrigation of a lawn or garden, a half-acre or less in size Stockwater”
  • Agricultural exemptionConditional

    Washington contractor-registration requirements for qualifying agricultural construction or operations, including in Wahkiakum County.

    • The quoted exemption applies to the enumerated agricultural work except when the work is performed by a registered contractor.
    “(10) Any construction or operation incidental to the construction and repair of irrigation and drainage ditches of regularly constituted irrigation districts or reclamation districts; or to farming, dairying, agriculture, viticulture, horticulture, or stock or poultry raising; or to clearing or other work upon land in rural districts for fire prevention purposes; except when any of the above work is performed by a registered contractor;”
    One more reviewed finding on this topic
    • Available (with conditions) — Temporary growing structures used solely for production of horticultural plants in Washington.
      “The provisions of this chapter do not apply to temporary growing structures used solely for the production of horticultural plants including ornamental plants, flowers, vegetables, and fruits. A temporary growing structure is not considered a building or structure for purposes of this chapter.”
  • Campground & park staysLimited

    Recreational vehicles in the context of Washington's manufactured/mobile-home community statutes

    • The rule defines an RV as temporary and transient living quarters.
    • The RV is not occupied as a primary residence.
    • The RV is not immobilized or permanently affixed to a manufactured/mobile home lot.
    • This claim does not establish general statewide siting permission on private land; local land-use and building rules may apply.
    “(12) "Recreational vehicle" means a travel trailer, motor home, truck camper, or camping trailer that is primarily designed and used as temporary living quarters, is either self-propelled or mounted on or drawn by another vehicle, is transient, is not occupied as a primary residence, and is not immobilized or permanently affixed to a manufactured/mobile home lot.”
    One more reviewed finding on this topic
    • Limited — Camping and temporary occupancy in Washington State Parks facilities
      “The maximum length of stay shall be no more than 10 nights in one park within a 30-day period. Total nights stayed by the same camping party must not exceed 90 nights per calendar year in all state parks. These limitations shall not apply to those individuals who meet the qualifications of WAC 352-32-280 and 352-32-285.”
  • county zoning authorityGeneral

    Washington counties adopting zoning and related official controls for county jurisdiction, including unincorporated areas.

    • A county must create a planning agency as authorized in RCW 36.70.030 and RCW 36.70.040 before engaging in the chapter's planning program.
    • Zoning maps may be adopted only for areas covered by a comprehensive plan containing at least a land use element and a circulation element.
    • Zoning regulations may address land uses, building location and dimensions, yards and open spaces, population density, lot coverage, parking, and minimum gross floor area requirements for single-family detached dwellings.
    • The cited enabling provisions do not state a population threshold, named-county limitation, or special geographic limitation.
    “Any board, by ordinance, may establish classifications, within each of which, specific controls are identified, and which will regulate:”
    One more reviewed finding on this topic
    • General — Washington counties may plan and adopt zoning and other official controls for county land, including unincorporated areas, through their boards and planning agencies.
      “Such official controls may include, but are not limited to, ordinances establishing zoning, subdivision control, platting, and adoption of detailed maps.”
  • county building authorityGeneral

    Washington counties requiring and enforcing building permits and adopting amendments to the state building code for residential construction within county jurisdiction, including unincorporated areas.

    • The state building code must be enforced by counties and cities within their jurisdictional boundaries.
    • A county without a building department must contract with another county, city, or approved inspection agency for enforcement.
    • County amendments may not diminish the minimum performance standards and objectives of the state building code.
    • Residential-building amendments are subject to approval by the state building code council under RCW 19.27.074(1)(b), except as provided by statute.
    • The building-permit definition incorporates exemptions in International Building Code section 105.2 and International Residential Code section R105.2.
    • Counties may adopt permit exemptions for certain specified R-3 or M-1 construction or alteration with total fair market value not exceeding $1,500, but the exemption does not remove substantive code standards.

    permit-exemption fair-market-value ceiling: <= 1500 USD (Applies only to certain construction or alteration of group R, division 3, or group M, division 1 occupancies under RCW 19.27.060(7); substantive code standards still apply.)

    “The state building code required by this chapter shall be enforced by the counties and cities. Any county or city not having a building department shall contract with another county, city, or inspection agency approved by the county or city for enforcement of the state building code within its jurisdictional boundaries.”

Inside cities and towns in Wahkiakum County

Municipal rules found while researching the county. They apply inside that city or town, not to unincorporated land.

  • Permit processPublished (with conditions)

    Building permits for structures erected within the incorporated Town of Cathlamet.

    • A building permit must be obtained from the town clerk before erection of any building.
    • The Cathlamet Municipal Code page states that the town hall has the official version of the code and that later ordinances may exist.
    “No building shall be erected in the town of Cathlamet without first obtaining a building permit from the town clerk. (Ord. 369 § 13, 1995)”

Still unanswered

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

  • Certificate of occupancy — Certificates of occupancy for county-administered construction.
  • Short-term rentals — Short-term rentals in Wahkiakum 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 Wahkiakum County, Washington

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

Wahkiakum County scores 67/100 on the Bolthole Index, a strong county profile. Its strengths: manageable long-term carry cost and strong self-sufficiency basics: 81.7″/yr rainfall plus 85.1% wooded land.

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

Wahkiakum County generally requires a residential building permit, and it has no county-wide zoning. Onsite septic is permitted by Wahkiakum County Health & Human Services (Public Health / Environmental 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.

Can you live in an RV or tiny home on your land in Wahkiakum County?

Living in an RV on your own land in Wahkiakum County is limited to specific cases: Recreational vehicles used as permanent residences in unincorporated Wahkiakum County. Permanent-residence RV use requires its own potable water and sewer or septic. The county page does not establish unrestricted RV occupancy or temporary camping rights. A tiny home is limited to specific cases. Confirm with the county before relying on it.

How much does land cost in Wahkiakum County, Washington?

Land in Wahkiakum County runs about $6,630 per acre, based on the latest county data.

What is the water situation in Wahkiakum County?

Wahkiakum County gets about 81.7" of rain a year, with severe drought in roughly 4.8% of years.

How remote is Wahkiakum County?

A typical private-land location has about 19,767 people within 15 miles and 3,434,627 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

How Wahkiakum compares in Washington

Compare side-by-side →See all 39 Washington counties ranked →