Spokane County, WA Building Permits, Zoning & Septic Rules

Unincorporated Spokane County, Washington requires building permits for residential construction, although a single-story tool or storage shed under 200 square feet is exempt¹. County zoning also controls allowed uses and development standards². Spokane Regional Health District permits and inspects on-site sewage systems using less than 3,500 gallons per day³.

At a glance

Building permit: Required for residential construction; single-story tool or storage sheds under 200 square feet are exempt¹
Zoning: Spokane County zones unincorporated land itself, through Building & Planning under the Growth Management Act⁴
Septic permits: Spokane Regional Health District permits and inspects systems below 3,500 gallons per day³
Owner-builder exemption: Available from contractor registration for work on your own property, except work done to sell, demolish, or lease it; permits still apply⁵
Tiny home: Allowed up to 400 square feet if built to the Washington State Building Code, with local approval depending on where it's placed⁶
Minimum dwelling size: 190 square feet of habitable space minimum, with at least one room of 120 square feet or more⁷
Manufactured home: A building permit is required, and the home must meet the residential standards of its zoning district⁸
Septic soil difficulty: Only 2.6% of county soils are free of severe limits for a conventional septic drain field⁹

Who to call

Building permits

Spokane County Building & Planning Department

Building permits, plan review, zoning administration, and long-range planning for unincorporated Spokane County

509-477-3675

1026 W Broadway Avenue, 1st Floor, Spokane, WA 99260

Also useful

Spokane County Building & Planning - Frequently Asked Questions

Published answers from Building & Planning on which codes apply, permit expiration, extensions, online service area, and design criteria such as snow load

Online permits →

Septic permits

Spokane Regional Health District (SRHD) - On-Site Sewage (Septic) Systems

On-site sewage (septic) system permits, design review, and inspections for Spokane County

509.324.1560 ext. 1

1101 W. College Ave., Spokane, WA 99201

Contact details are copied from each office’s official page and were checked against it on September 29, 2026.

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

Yes. Unincorporated Spokane County requires a building permit before constructing a new residential structure or enlarging, remodeling, relocating, or demolishing an existing one¹. A single-story residential tool or storage shed under 200 square feet is exempt from the building-permit requirement¹. The Washington State Building Code applies to buildings and structures in Spokane County, subject to statutory exceptions¹⁰. The county also uses the 2021 International Building Code and 2021 International Residential Code, as modified by state and county provisions¹¹. Washington's agricultural exemption concerns contractor registration for specified work incidental to farming and similar operations; it does not establish a Spokane County exemption from building or land-use permits¹². Ask Building & Planning about any project beyond the specific small-shed exemption before work begins.

Who is the Spokane County building department, and how do you reach them?

The Spokane County Building & Planning Department evaluates and issues land-use and building permit applications and enforces site-development regulations governing building use and occupancy¹³. The office is at 1026 W Broadway Avenue, 1st Floor, Spokane, WA 99260, and the phone line is 509-477-3675¹⁴. Online applications are accepted for unincorporated Spokane County, the City of Millwood, and the Towns of Rockford and Spangle¹⁵. A complete, clearly compliant new-house application may be issued within 2–3 days when septic is not involved; new construction involving a new or altered septic system needs at least 7–10 days for health-district review¹⁶. Most land-use applications require a pre-application conference, whose published 2026 fee is $767.88 and non-refundable¹⁷. A building permit expires three years after issuance, with one possible extension of up to 180 days¹⁵.

Does Spokane County have zoning?

Yes. Spokane County's zoning text and official maps govern unincorporated land¹⁸. District tables determine permitted, prohibited, limited, and conditional uses, along with standards such as lot size, building height, density, frontage, storage, and lighting¹⁹. There is no single countywide setback or height number: the available mixed-use rule, for example, sets a 20-foot setback for certain buildings beside a single-family zone or residence and applies its own height limits²⁰²¹. Ask Building & Planning for the parcel's exact district and dimensional table rather than applying that example to rural residential land. Spokane County also regulates divisions of land, so a proposed split must conform to subdivision rules as well as zoning²². A manufactured or mobile home on an individual lot requires a building permit and must meet the residential development standards of its zoning district⁸.

How do septic permits work in Spokane County?

Spokane Regional Health District permits new and changed on-site sewage systems for single-family homes, small businesses, and apartment buildings using less than 3,500 gallons per day; larger systems and industrial wastewater fall to state agencies³. The Septic Systems line is 509.324.1560 ext. 1, and the office is at 1101 W. College Ave., Spokane, WA 99201²³. SRHD reviews each covered system, permits it, and inspects it after installation²⁴. Operating permits renew every one or three years depending on system type, with inspection and maintenance required before renewal²⁵²⁴. Only 2.6% of county soils lack severe limits for a conventional drain field, so arrange the site evaluation before fixing the house location⁹. A property notified that county sewer is available must connect and abandon its septic tank within one year²⁶.

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

We could not confirm that long-term RV occupancy is allowed on private land in unincorporated Spokane County. Washington's manufactured-home-community statute describes an RV as temporary living quarters that are not a primary residence and are not permanently fixed to a lot, but that definition does not create permission to live in one on an ordinary parcel²⁷. Ask Spokane County Building & Planning about the parcel's zoning district and any time limits before moving an RV onto the land. Washington recognizes tiny houses of up to 400 square feet when built to the state building code, but foundation, installation, and location still require local approval⁶. A code-regulated dwelling must provide at least 190 square feet of habitable space, including at least one room of 120 square feet or more⁷. A manufactured or mobile home requires a building permit and compliance with its zoning district's residential standards⁸.

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

Ask Spokane County Building & Planning for the parcel's zoning district, development standards, and subdivision status²²².
Determine whether county sewer is available; after notice of availability, a property must connect and abandon its septic tank within one year²⁶.
If septic is needed, contact Spokane Regional Health District before fixing the house location because only 2.6% of county soils lack severe conventional-drain-field limits²⁵⁹.
Obtain an approach permit from the Division of Engineering and Roads before connecting a private driveway to a county public road²⁸.
Submit the project-specific plans and supporting documents required for the residential building-permit application²⁹.
Build to the applicable state, county, and adopted construction codes¹⁰¹¹. Ask Building & Planning which inspections apply.
Keep the permit timeline in view: a building permit expires after three years unless the Director grants one extension of up to 180 days¹⁵.

What to check before you buy land in Spokane County

Start with the zoning map, district standards, and legal-lot status because Spokane County's allowed uses and development standards vary by district and land divisions are regulated²²². Only 2.6% of county soils lack severe limitations for a conventional septic drain field, so do not assume an undeveloped parcel will support the least expensive system⁹. About 75.1% of county land has slopes of 15% or less, while 33.9% is wooded, making parcel-level grading, clearing, and access checks worthwhile³⁰³¹. Any development on an unincorporated parcel containing a FEMA-designated floodplain requires a Floodplain Development Permit³². A driveway connecting to a county public road needs an approach permit, and installation must be inspected and accepted before dwelling occupancy²⁸. We could not confirm the private-well permit rule, so ask the Washington Department of Ecology and Spokane Regional Health District what the parcel requires. The effective property-tax rate is about 0.9%, with a median annual bill of $3,196³³³⁴.

Watch-outs

Minimum lot size, setbacks, building height, and lot coverage vary by zoning district, so obtain the parcel's designation and applicable standards from Spokane County Building & Planning before buying¹⁹.
Washington's tiny-house allowance is written for structures built to the state building code; a wheeled structure that doesn't meet that definition may instead be regulated as a recreational vehicle or park model, with different rules⁶.

Sources

Written September 29, 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.

How Spokane County scores

Seclusion57100% ev.

Self-Sufficiency50100% ev.

Admin Boringness41100% ev.

Durability72100% ev.

Property Autonomy50100% ev.

Carry Cost73100% 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 →

$429kTypical home

0.9%Property tax

$4,951Land / acre

20.4"Annual rain

8.1% of yrsSevere drought

5.4 / yr (+4.9)Mid-century 100°F days

29.4 daysMid-century dry spell

0.8" (+5.8%)Mid-century 1-day rain

1.29×Wildfire change factor

100%Forward climate coverage

$1,230Home insurance / yr

2.2% / yrInsurance growth

0.61%Nonrenewal rate

county median (2+ published ZIPs)Insurance basis

7,673People within 30 min

1,000,478People within 2 hr

122,435Radius comparison (15 mi)

312.6People / sq mi

2.6%Federal land

75.1%Land at 15% slope or less

2.6%Septic soil without severe limits

26,849 acWorkable land screen

33.9%Wooded land

36.4 tonsBiomass / forest ac

47.1°FAvg temp

Answers from the rulebook for Spokane County

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

Spokane County rules

Building permitRequired
Residential construction in unincorporated Spokane County.
- Single-story residential accessory buildings under 200 square feet are exempt.
- Permits must be obtained before construction.
accessory-building exemption threshold: < 200 square feet (single story tool or storage sheds)
“In general you will need a building permit any time you construct a new structure or enlarge, remodel, relocate or demolish an existing structure. Residential accessory buildings such as tool and storage sheds which are a single story and less than 200 square feet in area are exempt from permit requirements. Permits are required to be obtained prior to construction.”
Residential Building Permits ↗Re-checked Sep 29, 2026
Building code adoptedAdopted (with conditions)
Construction codes in unincorporated Spokane County.
- The listed codes may be modified by the State Building Code Council and Spokane County Code, Chapter 3.
building code edition: 2021 International Building Code · residential code edition: 2021 International Residential Code
“What construction codes are in effect in the unincorporated areas of the County? 2021 International Building Code 2021 International Residential Code”
Frequently Asked Questions — construction codes ↗Re-checked Sep 25, 2026
County-wide zoningPresent (with conditions)
Spokane County zoning regulation in the unincorporated county.
- The county zoning code is maintained by the Division of Building and Planning.
- Specific dimensional standards vary by zoning district and use.
“This code, adopted as an official control under chapter 36.70 RCW and chapter 36.70A RCW, shall consist of zoning text and a series of official zoning maps.”
County Code ↗Re-checked Sep 25, 2026
Zoning districtsPublished (with conditions)
Spokane County zoning districts and district-specific development standards.
- The zoning code contains district matrices and standards for residential, rural, industrial, resource, and other zones.
- Applicable standards vary by zoning district and use.
“The third section includes Zone Classifications and Overlay Zones (chapters 14.600 and 14.700). These chapters provide general regulations for permitted, not permitted, limited, and conditional uses in regular zones and overlay zones.”
Spokane County Zoning Code ↗Re-checked Sep 29, 2026
2 more reviewed findings on this topic
- Published (with conditions) — Zoning districts and district-specific development standards in unincorporated Spokane County.
  “The location and boundaries of the zones established by this code are shown upon the zoning maps, which are hereby incorporated into the provisions of this Code.”
  Spokane County Zoning Code ↗Re-checked Sep 25, 2026
- Published — Zoning districts and district-specific development standards in unincorporated Spokane County.
  “The third section includes Zone Classifications and Overlay Zones (chapters 14.600 and 14.700). These chapters provide general regulations for permitted, not permitted, limited, and conditional uses in regular zones and overlay zones. The standards include lot sizes, height of buildings, densities, frontage requirements, storage, lighting, and other related matters.”
  Spokane County Zoning Code ↗Re-checked Sep 29, 2026
SetbacksDistrict specific (with conditions)
Mixed-use development under Spokane County Zoning Code section 14.608.300.
- Multiple-family, commercial, or mixed-use buildings adjacent to a single-family residential zone or existing single-family residence must meet the stated setback.
- No other setbacks are required under this section except those mandated by adopted building codes.
setback from shared property line: 20 feet (Adjacent multiple-family, commercial, or mixed-use building next to single-family residential zone or existing single-family residence.)
“Any multiple family, commercial or mixed use building adjacent to a single family residential zone or an existing single family residence shall be set back from the shared property line by 20 feet. No other setbacks are required, except as mandated by the building codes adopted by Spokane County.”
Spokane County Zoning Code ↗Re-checked Sep 25, 2026
Building heightDistrict specific (with conditions)
Mixed-use development under Spokane County Zoning Code section 14.608.300.
- Pitched roofs and accessible decks may extend above the height limit only if there is no enclosed, habitable space above the height limit.
- Buildings within 60 feet of a Low Density Residential zone are limited to 35 feet above grade.
- Beyond 60 feet, additional height is allowed at the stated ratio until the zone maximum is reached.
maximum building height: 50 feet (May increase by 10 feet if structured parking is provided underneath the building or within the first floor.) · height near Low Density Residential zone: <= 35 feet (Within 60 feet of the zone.) · additional height ratio: 1 foot vertical per 3 feet horizontal (Beyond the 60-foot transition limit until the zone maximum is reached.)
“The maximum building height is 50 feet. The maximum height may be increased by 10 feet, if structured parking is provided either underneath the building or within the first floor. Pitched roofs and accessible decks may extend above the height limit, provided that there is no enclosed, habitable space above the height limit.”
Spokane County Zoning Code ↗Re-checked Sep 25, 2026
Manufactured homesLimited
Establishment of a manufactured or mobile home on an individual lot or in a manufactured-home park.
- A building permit is required.
- The manufactured home must conform to the minimum residential development standards of the applicable zoning district.
“A building permit is required for the establishment of a manufactured home or a mobile home on an individual lot or in a manufactured home park in accordance with Title 3 of the Spokane County Code. An individual manufactured home shall conform to the minimum residential development standards of the zone in which it is located.”
Spokane County Zoning Code ↗Re-checked Sep 25, 2026
Who permits septicMixed (with conditions)
On-site sewage systems in Spokane County.
- SRHD permits and inspects systems using less than 3,500 gallons per day.
- Washington Department of Health and Department of Ecology enforce regulations for larger systems and systems treating industrial wastewater.
daily flow threshold: < 3500 gallons per day (larger or industrial systems are regulated by Washington Department of Health and Department of Ecology)
“The Liquid Waste program permits and inspects on-site sewage systems using less than 3,500 gallons of water per day. Washington State Department of Health and Washington Department of Ecology enforce regulations for larger sewage systems and those systems that treat industrial wastewater.”
Septic Systems ↗Re-checked Sep 29, 2026
2 more reviewed findings on this topic
- Local (with conditions) — On-site sewage systems using less than 3,500 gallons per day in Spokane County and the SRHD jurisdiction.
  “The Liquid Waste program permits and inspects on-site sewage systems using less than 3,500 gallons of water per day. Washington State Department of Health and Washington Department of Ecology enforce regulations for larger sewage systems and those systems that treat industrial wastewater.”
  Septic Systems ↗Re-checked Sep 25, 2026
- Local — On-site sewage systems in Spokane County within SRHD jurisdiction, for systems using less than 3,500 gallons per day.
  “The Liquid Waste program permits and inspects on-site sewage systems using less than 3,500 gallons of water per day. Washington State Department of Health and Washington Department of Ecology enforce regulations for larger sewage systems and those systems that treat industrial wastewater.”
  Septic Systems ↗Re-checked Sep 29, 2026
Septic permitRequired
New or modified on-site sewage systems for single-family homes, small businesses, and apartment buildings using less than 3,500 gallons per day.
- Fees vary by system size and type.
- Systems receive renewable permits for one or three years depending on system type.
daily flow threshold: < 3500 gallons per day · renewal period: 1 or 3 years (depends on on-site sewage system type)
“Spokane Regional Health District (SRHD) tracks and issues permits for new on-site sewage systems and changes to existing systems designed for single-family homes, small businesses, and apartment buildings (systems less than 3,500 gallons per day). Fees vary based on the size and type of system.”
New Systems or Changes to Existing Systems ↗Re-checked Sep 29, 2026
One more reviewed finding on this topic
- Required — New or changed on-site sewage systems for single-family homes, small businesses, and apartment buildings using less than 3,500 gallons per day.
  “Spokane Regional Health District (SRHD) tracks and issues permits for new on-site sewage systems and changes to existing systems designed for single-family homes, small businesses, and apartment buildings (systems less than 3,500 gallons per day). Fees vary based on the size and type of system.”
  New Systems or Changes to Existing Systems ↗Re-checked Sep 25, 2026
Septic inspectionRequired
On-site sewage systems under SRHD jurisdiction.
- Systems are inspected after installation.
- Inspection and maintenance are required before permit renewal.
- Renewable permits are issued for one or three years depending on system type.
“Systems are: Reviewed for compliance with regulations Permitted Inspected after installation Once installed, septic systems are issued renewable permits for one or three years, depending on the on-site septic system type. On-site sewage system inspection and maintenance is required prior to permit renewal.”
New Systems or Changes to Existing Systems ↗Re-checked Sep 25, 2026
One more reviewed finding on this topic
- Required — On-site sewage systems regulated by SRHD.
  “Systems are: Reviewed for compliance with regulations Permitted Inspected after installation Once installed, septic systems are issued renewable permits for one or three years, depending on the on-site septic system type. On-site sewage system inspection and maintenance is required prior to permit renewal.”
  New Systems or Changes to Existing Systems ↗Re-checked Sep 29, 2026
Mandatory utility hookupConditional
Properties notified that Spokane County sewer service is available.
- Each property must connect to sewer and abandon its septic tank within one year after notification of sewer availability.
- A sewer connection permit is required.
- The reviewed rule concerns sewer connection; it does not establish countywide water connection requirements.
connection deadline: 1 year after notice
“Each property is required by County Code to connect to the sewer and abandon their septic tank within one year of being notified of the availability of sewer service.”
Frequently Asked Questions ↗Re-checked Sep 25, 2026
Subdividing landRegulated (with conditions)
Subdivision and short-plat applications handled by Spokane County.
- The 2026 fee schedule lists preliminary and final plats, short plats, and binding site plans.
- Fees include base fees and per-lot increments.
preliminary plat base fee: 8227.25 USD (Plus $22.77 per lot.) · final plat base fee: 3949.08 USD (Plus $29.70 per lot.)
“Preliminary Plat .................... $8,227.25 $22.77/lot Final Plat ................................. $3,949.08 $29.70/lot Change of Conditions ........ $5,649.38 $22.77/lot Preliminary Short Plat ........ $5,155.74 $22.77/lot Final Short Plat ..................... $2,961.80 $29.70/lot”
2026 Land Use Fee Schedule BP-4P ↗Re-checked Sep 25, 2026
One more reviewed finding on this topic
- Regulated (with conditions) — Division of land and subdivision-related development in unincorporated Spokane County.
  “Building sites must conform to applicable regulations governing the division of land. Other local ordinances could impact your project depending upon its specific nature and location.”
  Residential Building Permits ↗Re-checked Sep 29, 2026
Driveway accessRequired
Private driveway approaches connecting to county public roads and access to residential dwellings.
- An approach permit is required to connect to a county public road.
- Driveway installation inspection and acceptance are required before dwelling occupancy.
- Driveways over 150 feet require a turnaround within 150 feet of the dwelling.
- Private driveway standards include grade, width, turnout, drainage, and curve requirements.
maximum grade: 12%-14% (outside right-of-way) · minimum clear travel width: >= 12 feet (all-weather surface) · turnaround threshold: > 150 feet (turnaround required)
“Approach permits are required from the Division of Engineering and Roads to connect to any county public road. Private driveways constructed prior to obtaining building permits may require a grading permit.”
Driveways ↗Re-checked Sep 29, 2026
Building in a floodplainLimited
Fill, grading, excavation, and crossing structures in Spokane County floodplain areas.
- In A or shaded X zones, development may not increase the base-flood water-surface elevation by more than one foot.
- In AE, AO, or AH zones with provided base-flood elevations, the limit is one-tenth of a foot, subject to stated subdivision and county-engineer/public-works-director exceptions.
- Impacted property owners must provide written, notarized approval when the increase exceeds one-tenth of a foot.
- Engineers must address floodway, bridge, and culvert requirements.
base-flood elevation increase in A or shaded X zones: <= 1 foot · base-flood elevation increase in AE, AO, or AH zones: <= 0.1 foot (Specified subdivision and county-discretion exceptions.)
“In any AE, AO or AH zones, where base flood elevations have been provided, the development may not increase the surface water elevation of the base flood by more than one-tenth of a foot at any point with the following exceptions:”
Floodplain Requirements ↗Re-checked Sep 25, 2026
One more reviewed finding on this topic
- Required — Development on parcels containing FEMA-designated floodplain in unincorporated Spokane County.
  “The Division of Engineering and Roads administers this code for the unincorporated areas of Spokane County. Spokane County’s Flood Damage Protection Code regulates any development that will occur on property all or a portion of which is determined by FEMA to be in a floodplain.”
  Floodplain Information ↗Re-checked Sep 29, 2026
Permit feesPublished (with conditions)
Spokane County land-use and building permit applications.
- Pre-application fees are non-refundable.
- Other agency fees may apply.
- Fees are due when an application is deemed complete and accepted.
- An 80% refund may apply before county evaluation begins; a 50% refund may apply before legal notice or approval action; no refund generally applies after an administrative decision or notice mailing.
- Specific fees should be verified with planning staff.
preapplication fee: 767.88 USD
“A pre-application conference is required for most land use applications to outline the evaluation and approval process and to identify potential issues or concerns before submitting a formal application. Pre-application fees are non-refundable.”
2026 Land Use Fee Schedule BP-4P ↗Re-checked Sep 25, 2026
Permit processPublished (with conditions)
Residential building-permit application and review process in unincorporated Spokane County.
- Applications require parcel information, legal description, address, site plans, construction drawings, and other listed information.
- Projects involving septic, sewer, floodplain, driveway approaches, utilities, or critical areas may require additional agency approvals or permits.
new-house processing time without septic: 2-3 days (complete application and plans that clearly conform to applicable codes and ordinances) · new construction with septic: 7-10 days (minimum time frame for SRHD sewage-disposal review)
“For a new house, when a septic system is not involved, your application and plans are complete, and the proposal clearly conforms to the codes and ordinances adopted by Spokane County, the permit may be issued within 2–3 days. [...] In the case of new construction involving installation of a septic system, or alterations to a septic system, a minimum time frame of 7 to 10 days is necessary to allow review of the sewage disposal system by the Spokane Regional Health District.”
Residential Building Permits ↗Re-checked Sep 29, 2026
2 more reviewed findings on this topic
- Published (with conditions) — County land-use and building permit applications.
  “The Planning Department oversees the evaluation and issuance of all land-use and building permit applications and the enforcement of site development regulations governing the use and occupancy of buildings.”
  2026 Land Use Fee Schedule BP-4P ↗Re-checked Sep 25, 2026
- Published (with conditions) — Residential building permit application process in unincorporated Spokane County.
  “Use the table below to determine submittal requirements for your application based on the scope of work proposed. One (1) complete PDF version of plans, supplemental documents shall be submitted in PDF format and saved as individually-named PDF files separate from the drawing files.”
  Residential Building Permit Application ↗Re-checked Sep 29, 2026

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;”
RCW 18.27.090 — Exemptions ↗Re-checked Sep 21, 2026
2 more reviewed findings on this topic
- Conditional — Washington contractor-registration exemption for a person working on their own property or personal residence.
  “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;”
  RCW 18.27.090: Exemptions ↗Re-checked Sep 29, 2026
- Available (with conditions) — Contractor-registration requirements for persons working on their own property or personal residence.
  “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;”
  RCW 18.27.090 — Exemptions ↗Re-checked Sep 29, 2026
Minimum dwelling sizeSpecified
Dwelling units regulated by Washington's state building code.
- The rule specifies habitable-space and room-area minimums, not a zoning minimum lot or gross floor-area standard.
- Kitchens are expressly excepted from the minimum floor-area requirement.
- Efficiency dwelling units must comply with Sections 1208.1 through 1208.4 and must have a separate closet, required kitchen facilities, light and ventilation, and a separate bathroom as stated in the source.
- The current rule text states WSR 23-23-102 was filed 11/15/23 and effective 3/16/24.
minimum habitable space: >= 190 square feet · minimum area of at least one room: >= 120 square feet · minimum net floor area of sleeping units and other habitable rooms: >= 70 square feet (Kitchens are not required to be of a minimum floor area.)
“1208.3 Dwelling unit size. Dwelling units shall have a minimum of 190 square feet (17.7 m 2) of habitable space. 1208.4 Room area. Every dwelling unit shall have not less than one room that shall have not less than 120 square feet (11.2 m 2) of net floor area. Sleeping units and other habitable rooms of a dwelling unit shall have a net floor area of not less than 70 square feet (6.5 m 2). EXCEPTION: Kitchens are not required to be of a minimum floor area.”
WAC 51-50-1208 — Section 1208—Interior space dimensions ↗Re-checked Sep 21, 2026
Tiny homesAllowed (with conditions)
Occupancy and placement of tiny houses in Washington
- A tiny house may be built on wheels and may not exceed 400 square feet including kitchen, bathroom, and sleeping/living area.
- It must be built to the Washington State Building Code.
- Approval depends on where it is built; local building-department requirements and permits apply to foundation, installation, and location.
- A wheeled structure that is not a tiny house as described may instead be a recreational vehicle or park model.
- A manufactured home, including a tiny manufactured home, requires consultation with the local building department regarding where it may be located.
maximum area: <= 400 square feet
“A tiny house is a dwelling that may be built on wheels and is no larger than 400 square feet, including a kitchen, bathroom, and sleeping/living area, and must be built to the Washington State Building Code. The approval process for a tiny house depends on where it's built.”
Tiny Houses ↗Re-checked Sep 21, 2026
Accessory dwellingsAllowed (with conditions)
Accessory dwelling units in portions of Washington cities, towns, and counties located within designated urban growth areas and subject to the Growth Management Act requirements
- Cities and counties planning under the chapter must adopt or amend ordinances and development, zoning, and other official controls to implement the statutory requirements.
- The requirements apply only in portions of towns, cities, and counties within designated urban growth areas.
- Local governments may still apply public-health, safety, building-code, environmental-permitting, on-site-wastewater, and generally applicable development regulations.
- Local governments may restrict or prohibit ADUs where development is restricted because of on-site sewage infrastructure, critical areas, or other unsuitable physical characteristics.
- Under RCW 36.70A.681, at least two ADUs must be allowed on qualifying lots in configurations specified by statute, subject to listed exceptions and limitations.
- The statutory requirements do not apply to lots designated with critical areas or buffers, or to specified impaired or threatened potable-water-reservoir watersheds.
minimum ADUs in qualifying configurations: >= 2 accessory dwelling units per qualifying lot (Applies to lots in all zoning districts within an urban growth area that allow single-family homes, subject to statutory exceptions.)
“The city or county must allow at least two accessory dwelling units on all lots that are located in all zoning districts within an urban growth area that allow for single-family homes in the following configurations:”
RCW 36.70A.680 — Accessory dwelling units—Local regulation ↗Re-checked Sep 21, 2026
Agricultural exemptionAvailable (with conditions)
Temporary growing structures used solely for production of horticultural plants in Washington.
- The exemption is limited to temporary growing structures.
- The structures must be used solely for production of horticultural plants, including ornamental plants, flowers, vegetables, and fruits.
- The statute states that a temporary growing structure is not considered a building or structure for purposes of chapter 19.27 RCW.
- This is not a general exemption for residences or all agricultural buildings.
“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.”
RCW 19.27.065 — Exemption—Temporary growing structures used for production of horticultural plants ↗Re-checked Sep 21, 2026
One more reviewed finding on this topic
- Conditional — Washington contractor-registration exemption for construction or operations incidental to farming, dairying, agriculture, viticulture, horticulture, stock, or poultry raising.
  “The registration provisions of this chapter do not apply to: [...] (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;”
  RCW 18.27.090: Exemptions ↗Re-checked Sep 29, 2026
Campground & park staysLimited
Camping and temporary occupancy in Washington State Parks facilities
- Camping is permitted only in areas specifically designated or marked for camping, or as directed by a ranger.
- State park facilities may not be used for residence purposes.
- Continuous occupancy is limited to no more than 10 nights in one park within a 30-day period and no more than 90 nights per calendar year in all state parks, subject to stated qualifications in WAC 352-32-280 and WAC 352-32-285.
- Occupants must vacate by 1:00 p.m. when the applicable fee is unpaid, the occupancy limit expires, or the site is reserved by another party; an additional camping fee may apply after checkout.
maximum stay in one park: <= 10 nights per 30-day period (Limitations do not apply to individuals qualifying under WAC 352-32-280 and WAC 352-32-285.) · maximum stay in all state parks: <= 90 nights per calendar year (Limitations do not apply to individuals qualifying under WAC 352-32-280 and WAC 352-32-285.) · checkout time: 1:00 p.m. (Applies when the fee is unpaid, the occupancy limit has expired, or the site is reserved by another party.)
“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.”
WAC 352-32-030 — Camping ↗Re-checked Sep 21, 2026
One more reviewed finding on this topic
- Limited — Recreational vehicles in the context of Washington's manufactured/mobile-home community statutes
  “(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.”
  RCW 59.30.020 — Definitions ↗Re-checked Sep 21, 2026
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:”
RCW 36.70.050 — Authority for planning ↗Re-checked Sep 21, 2026
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.”
RCW 19.27.050 — Enforcement ↗Re-checked Sep 21, 2026

Still unanswered

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

Inspections — Building inspections for construction in unincorporated Spokane County.
Certificate of occupancy — Certificate-of-occupancy requirements in unincorporated Spokane County.
Minimum lot size — Minimum lot size in unincorporated Spokane County.
Lot coverage — Lot coverage in unincorporated Spokane County.
Living in an RV — Long-term or residential RV occupancy on private land.

4 more unanswered

Camping on your land
Off-grid sanitation
Well permit
Short-term rentals

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.

Water rights & wells in Spokane County

Whether a new home can legally get its own water here — the sub-state groundwater regime, from Washington’s water agency.

Actively managed

This basin is under active state management — new water use is scrutinized, though a domestic well is usually still allowed.

Household wellExempt up to a limit

RCW 90.44.050 exempts up to 5,000 gpd for domestic use, but the 2018 Streamflow Restoration Act caps NEW permit-exempt domestic wells at 3,000 gpd/connection in some basins and 950 gpd (350 gpd indoor in drought) in others, and new post-2020 wells in the adjudicating Nooksack basin are limited to ~500 gpd indoor.

Limit: 5,000 gpd base (RCW 90.44.050); capped to 3,000 or 950 gpd/connection in streamflow-restoration basins; ~500 gpd indoor for new Nooksack wells

Washington Dept of Ecology — Groundwater permit exemption ↗

Streamflow Restoration 3,000-gpd basins (RCW 90.94.020)partial of county
New permit-exempt domestic wells capped at a maximum annual-average 3,000 gpd per connection; larger/new water-right permits generally unavailable due to instream-flow rules.
Washington Legislature — RCW 90.94.020 ↗

Hybrid state (appropriation + riparian). Groundwater rules change and basin boundaries follow the aquifer, not the county line — confirm current well and appropriation rules with the Washington state water agency before you buy or drill.Groundwater governance as of Jul 2026, cited to each administering agency.

Living off-grid in Spokane County, Washington

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

Spokane County scores 64/100 on the Bolthole Index, a strong county profile. Its strengths: manageable long-term carry cost and mixed durability signals. Watch-outs: more administrative friction around building and land use.

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

Spokane County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Spokane Regional Health District. 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 Spokane County, Washington?

Land in Spokane County runs about $4,951 per acre, based on the latest county data.

What is the water situation in Spokane County?

Spokane County gets about 20.4" of rain a year, with severe drought in roughly 8.1% of years. On water rights, Spokane County lies in the Streamflow Restoration 3,000-gpd basins (RCW 90.94.020) — New permit-exempt domestic wells capped at a maximum annual-average 3,000 gpd per connection; larger/new water-right permits generally unavailable due to instream-flow rules..

How remote is Spokane County?

A representative private-land location has about 7,673 people within a 30-minute drive and 1,000,478 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.

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

At a glance

Who to call

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

Who is the Spokane County building department, and how do you reach them?

Does Spokane County have zoning?

How do septic permits work in Spokane County?

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

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

What to check before you buy land in Spokane County

Watch-outs

Sources

Spokane County in Washington

How Spokane County scores

Find land. Bring the promising ones back.

Parcel due diligence

Answers from the rulebook for Spokane County

Spokane County rules

Washington rules that apply here

Still unanswered

Water rights & wells in Spokane County

Living off-grid in Spokane County, Washington

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

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

How much does land cost in Spokane County, Washington?

What is the water situation in Spokane County?

How remote is Spokane County?

How Spokane compares in Washington