Bolthole Index

Snohomish County, Washington

Zoning, building permits and septic rules in Arlington, Washington

The City of Arlington, Washington sets its own zoning under Title 20 of the Arlington Municipal Code1 and enforces the 2021 International Building Code and Residential Code for building permits2. Septic is the surprise: private systems are allowed inside city limits only under a narrow exception, with the Snohomish Health District approving the system3.

At a glance

Zoning
City of Arlington, Title 20 Land Use Code (inside city limits only)1
Building permit
City Community & Economic Development; a permit is required under most circumstances4
Building code
2021 International Building and Residential Codes plus Washington amendments2
Septic
Narrow exception only; Snohomish Health District approves the system3
Water and sewer
Connection to public water and sewer is the rule5
Private wells
Not allowed except under special circumstances6
RV and tiny home living
Not confirmed; ask the city4

Who to call

Building permits

City of Arlington Community & Economic Development (building and land use)

Building permits, plan review and zoning questions inside Arlington city limits

360-403-3551

ced@arlingtonwa.gov

Septic permits

Snohomish County Health Department – Environmental Health Division

On-site sewage system (septic) design review, permitting and inspection, including the approval Arlington requires for a private system

425-339-5250

SHD-EHQ@snoco.org

3020 Rucker Avenue, Suite 104, Everett, WA 98201

Contact details are copied from each office’s official page and were checked against it on October 24, 2026.

Off-grid gear

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

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Does Arlington, Washington have zoning, and what does it mean for lot size and setbacks?

Yes. Inside Arlington city limits, zoning comes from the city's own Land Use Code, Title 20 of the Arlington Municipal Code, not from Snohomish County1. The code also covers subdivisions and boundary line adjustments7, and the city publishes its zoning districts and a zoning map8.

Lot size, setbacks and building height all vary by zoning district and are set in the density and dimensional table in Chapter 20.4891011. Find the parcel's district on the city's zoning map before you compare lots. In the residential ultra low capacity district, lots are larger so they can hold a septic system and reserve area as the Snohomish Health District requires12.

We could not confirm Arlington's rules on minimum home size, accessory structures or short-term rentals; ask Community & Economic Development at 360-403-35514.

Do you need a building permit in Arlington, and who issues it?

The City of Arlington issues building permits inside city limits through its Community & Economic Development department, which says a permit is required before constructing or installing equipment under most circumstances4. The city enforces the 2021 International Building Code and 2021 International Residential Code, along with Washington State amendments2.

The city lists a few exceptions: a one-story detached shed of 200 square feet or less, and fences not over 7 feet4. Washington also lets a city adopt a $1,500 minor-work permit exemption, but only if the city chooses to13; we could not confirm whether Arlington has. Call 360-403-3551 or email ced@arlingtonwa.gov before starting any project4.

Snohomish County's permit office handles building permits only outside city limits14.

How do septic permits work inside Arlington?

Arlington expects homes to connect to public sewer and public water. The city treats every lot inside its limits as served by a city sewer or water line, and private septic systems and wells are not allowed except under special circumstances15.

The private-septic exception requires a single lot of 5 acres or more, no public sanitary sewer line within 500 feet, and city and health district approval5. The owner must hand the city a copy of the Snohomish Health District permit before construction starts16. If public sewer later becomes available, the code requires connecting to it5.

Septic design, permits and final inspection are handled by the Snohomish County Health Department, not the city17. Washington requires a permit from the local health officer before work begins18. Private wells face a similar limit; we could not confirm what the well exception requires6.

Can you live in an RV or tiny home in Arlington?

We could not confirm Arlington's rules on RV living, camping or tiny homes inside city limits. Ask Community & Economic Development at 360-403-3551 before buying a lot with either plan4.

Snohomish County's rules do not apply inside the city. Outside city limits, in unincorporated Snohomish County, a recreational vehicle cannot be a primary residence19; see the Snohomish County page for land outside Arlington.

On tiny homes, Washington defines a tiny house as a dwelling of no more than 400 square feet that must meet the state building code, and approval depends on where it is built20. Because Arlington requires public water and sewer hookups, a tiny house in the city would also need those connections5.

Building a home in Arlington: the steps, in order

  1. Check the parcel's zoning district on the city's zoning map and read the dimensional rules in Chapter 20.48810.
  2. Confirm public water and sewer. Inside the city, a new home must connect to both unless the narrow private-septic exception applies5.
  3. If you plan a private system, get Snohomish Health District approval first, because the city requires a copy of the permit before construction16.
  4. Prepare plans to the city's 2021 codes and submit a building permit application to Community & Economic Development24.
  5. Request inspections as work proceeds; Washington's energy code requires a final inspection before the building is occupied21. We could not confirm Arlington's local inspection procedure, so ask the city.

What stays with Snohomish County, and what to check before you buy in Arlington

Septic design, permits and inspection stay with the Snohomish County Health Department even for addresses inside Arlington17. Land outside city limits falls under Snohomish County Planning and Development Services and the county's own zoning code22; the rules above do not carry over to it.

Before you buy, confirm the zoning district, whether public sewer reaches the lot, and whether the parcel is in a floodplain. Washington directs floodplain development permits through local government23; we could not confirm Arlington's floodplain procedure, so ask the city. A driveway onto a state highway needs written permission from the Washington Department of Transportation24.

Property tax is county-level: Snohomish County's effective rate is about 0.8%25.

Watch-outs

  • Private septic inside Arlington is the exception, not the default; confirm sewer availability and lot size before assuming a septic system is possible5.
  • County pages on RVs, accessory dwellings and building permits describe unincorporated land only, so they do not answer questions about a lot inside Arlington city limits26.
  • We could not confirm Arlington's rules on RV or tiny-home living, floodplain development, driveways or owner-builder work; call Community & Economic Development at 360-403-3551 before you rely on any assumption4.

Sources

  1. Zoning Code and Development Design Standards & Guidelines (City of Arlington, WA) (Arlington), quoted and re-checked
  2. UPDATED Residential Building Design Requirements (City of Arlington Community & Economic Development) (Arlington), quoted and re-checked
  3. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.60 Utilities (Arlington), quoted and re-checked
  4. City of Arlington Community & Economic Development (building and land use) (arlingtonwa.gov)
  5. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.60 Utilities (Arlington), quoted and re-checked
  6. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.60 Utilities (Arlington), quoted and re-checked
  7. Zoning Code and Development Design Standards & Guidelines (City of Arlington, WA) (Arlington), quoted and re-checked
  8. Zoning Code and Development Design Standards & Guidelines (City of Arlington, WA) (Arlington), quoted and re-checked
  9. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.48 Density & Dimensional Regulations (Arlington), quoted and re-checked
  10. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.48 Density & Dimensional Regulations (Arlington), quoted and re-checked
  11. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.48 Density & Dimensional Regulations (Arlington), quoted and re-checked
  12. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.48 Density & Dimensional Regulations (Arlington), quoted and re-checked
  13. WAC 51-16-080 — Permit exemptions guideline (Washington statewide rule), quoted and re-checked
  14. Residential Building Permits, quoted and re-checked
  15. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.60 Utilities (Arlington), quoted and re-checked
  16. Arlington Municipal Code Title 20 (Land Use Code) Chapter 20.60 Utilities (Arlington), quoted and re-checked
  17. Snohomish County Health Department – Environmental Health Division (snohd.org)
  18. WAC 246-272A-0200 Permit requirements (Washington statewide rule), quoted and re-checked
  19. Assistance Bulletin #53 — Recreational Vehicles, quoted and re-checked
  20. Tiny Houses (Washington statewide rule), quoted and re-checked
  21. WAC 51-11R-10500 — Section R105—Inspections (Washington statewide rule), quoted and re-checked
  22. Codes & Regulations, quoted and re-checked
  23. Planning & regulation — Washington State Department of Ecology (Washington statewide rule), quoted and re-checked
  24. RCW 47.32.150 — Approach roads, other appurtenances—Permit (Washington statewide rule), quoted and re-checked
  25. Effective property tax rate: Bolthole Index county data
  26. Planning & Development Services FAQs, quoted and re-checked

Written October 24, 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.

Answers from the rulebook for Arlington

Arlington’s own rules

  • Building code adoptedAdopted (with conditions)

    New residential construction and alterations inside Arlington city limits

    • Source is the city's residential plan-preparation checklist, not the adopting ordinance; the ordinance adopting these editions was not opened.
    • The checklist also lists Washington State amendments (WAC 51-50 state building code, WAC 51-51 state residential code).

    International Building Code edition enforced: 2021

    “the city of arlington currently enforces the following: international codes 1. 2021 international building code (ibc) 2. 2021 international residential code (irc)”
  • Local zoningPresent (with conditions)

    Land inside Arlington city limits: the city's own zoning ordinance, Title 20 Land Use Code

    • Zoning and the dimensional rules below apply only inside Arlington city limits, not to the unincorporated county area.
    “the city's zoning regulations are found in title 20 of the arlington municipal code.”
  • Zoning districtsPublished (with conditions)

    Zoning districts and zoning map for land inside Arlington city limits

    • Chapter 20.36 (zoning districts and map) is listed on the city's code page; the district list itself was not extracted.
    • Interactive map with parcel-level zoning is linked from the city page.
    “chapter 20.36 zoning districts and zoning map”
  • Minimum lot sizeDistrict specific (with conditions)

    All residential zones inside Arlington city limits (main single-family district numbers not extracted)

    • Minimum square footage per lot is set in table 20.48-51 (density and dimensional standards); the numeric table values were not readable in the opened text.
    • The chapter's table is labeled 20.48-1 in its header and 20.48-51 in the text, so the table reference should be checked.
    • Mobile home park and other exceptions in 20.44 apply (not opened).
    “all lots in each zone shall have at least the amount of square footage indicated in table 20.48-51: density and dimensional standards.”
    One more reviewed finding on this topic
  • SetbacksDistrict specific (with conditions)

    All zoning districts inside Arlington city limits (per-district setback numbers not extracted)

    • Setbacks are set in table 20.48-51; the table footnote states a rear setback for principal buildings of twenty feet and for detached accessory structures of five feet, but the footnote's district applicability was not confirmed.
    • Accessory building setbacks are governed by 20.48.050 (not extracted).
    “no portion of any building or any freestanding sign may be located on any lot closer to any lot line than is authorized in table 20.48-51: density and dimensional standards.”
  • Building heightDistrict specific (with conditions)

    Buildings in each zoning district inside Arlington city limits (per-district height numbers not extracted)

    • Chimneys, spires, elevator shafts, and similar appendages, flagpoles, and mechanical equipment are exempt from the district height limit subject to 20.48 conditions (not fully extracted).
    “building height limitations in the various zoning districts shall be as listed in table 20.48-51: density and dimensional standards.”
  • Who permits septicMixed (with conditions)

    On-site sewage systems on land inside Arlington city limits: the city certifies, and the Snohomish Health District approves the system (Snohomish County health district)

    • Private septic is allowed only under the narrow 20.60.120 exception; the city's rule does not allow it generally.
    • The Snohomish Health District's own rules and permit fees were not opened.
    “(5) the snohomish health district approves the system;”
  • Septic permitRequired

    Private on-site sewage system permitted under 20.60.120 inside Arlington city limits; a Snohomish Health District permit must be furnished to the city

    • Applies only when the 20.60.120(a) criteria are met (single lot of 5 acres or more, outside the aquifer recharge area, no public sanitary sewer within 500 feet, city certification, health district approval).
    • Health district fees are payable by the owner per 20.60.120(b).
    “the property owner shall furnish a copy of the snohomish health district permit to the city by prior to any construction work.”
  • Off-grid sanitationLimited

    Privately owned sanitary sewer systems inside Arlington city limits

    • Allowed only under the 20.60.120 special circumstances (single lot of 5 acres or more, outside the aquifer recharge area, no public sanitary sewer within 500 feet, city and health district approval).
    “privately owned and operated sanitary sewer systems and/or wells are not allowed within the city other than under special circumstances described in §20.60.120 (private sewage disposal) or §20.60.310 determining compliance with §20.60.300, respectively.”
  • Well permitLimited

    Private wells inside Arlington city limits

    • Private wells are not allowed within the city except under special circumstances described in 20.60.310 (not opened); the well permit and state well-driller rules were not located.
    “privately owned and operated sanitary sewer systems and/or wells are not allowed within the city other than under special circumstances described in §20.60.120 (private sewage disposal) or §20.60.310 determining compliance with §20.60.300, respectively.”
  • Mandatory utility hookupWater and sewer (with conditions)

    A new home or principal use on land inside Arlington city limits must connect to public water and public sewer

    • Sewer: 20.60.100 requires connection to a public sewer before completion or occupancy, except the 20.60.120 private-system exception (single lot of 5 acres or more, not in the aquifer recharge area, no public sanitary sewer line within 500 feet, city and health district approval).
    • Water: 20.60.300 requires connection to a public water system, except under special circumstances authorized by the public works director, and 20.60.310 (well exception) was not opened.
    • 20.60.120(d): connections to public sewer are required when public sewer becomes available.

    distance from lot to public sanitary sewer line that must exceed for private septic exception: > 500 feet · minimum single lot size for private septic exception: >= 5 acres

    “such uses or subdivision lots shall be connected to a public water system before the completion of the construction of such building or structure or, under special circumstances and with the public works director’s authorization, before any occupancy or use thereof.”
  • Subdividing landRegulated (with conditions)

    Land divisions and short plats inside Arlington city limits

    • Subdivision and boundary line adjustment rules are in Title 20 chapters 20.16 and 20.94 (not extracted).
    “the zoning code (also known as the land-use code) regulates such things as subdivisions, boundary line adjustments, permissible land uses, density and dimensional requirements”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Arlington or Snohomish County directly.

  • Building permit — Residential construction inside Arlington city limits
  • Owner-builder exemption — Owner-builder construction inside Arlington city limits
  • Inspections — Residential construction inside Arlington city limits
  • Certificate of occupancy — Occupancy of new homes inside Arlington city limits
  • Minimum dwelling size — Minimum dwelling size inside Arlington city limits
9 more unanswered
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Septic inspection
  • Agricultural exemption
  • Driveway access
  • Building in a floodplain
  • 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.

Unanswered questions are usually a sign that Arlington publishes no rule on the point, not that none exists. Snohomish County’s page lists the county offices to call.

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