Bolthole Index

Skagit County, Washington

Zoning, building permits and septic rules in Mount Vernon, Washington

Mount Vernon is a city in Skagit County, Washington. Mount Vernon adopts its own zoning, so inside its limits Mount Vernon’s rules apply, not the county’s. 6 rules below are quoted from official sources and independently re-checked, most recently on October 24, 2026. Rules for unincorporated land are on the Skagit County page.

Answers from the rulebook for Mount Vernon

Mount Vernon’s own rules

  • Building code adoptedAdopted (with conditions)

    Buildings and structures inside Mount Vernon city limits.

    • The city adopts the Chapter 19.27 RCW code editions as currently written and as amended in the future, subject to city modifications and amendments in Chapter 15.04.
    • The adopted codes regulate construction, alteration, removal, demolition, equipment, use, occupancy, location, and maintenance.
    “The edition of the below-listed codes identified in subsections A through L of this section shall be what is adopted in Chapter 19.27 RCW as it is currently written and as it is amended in the future; except for the modifications and/or amendments that are hereinafter specifically set forth within this chapter.”
  • Local zoningPresent (with conditions)

    Land inside Mount Vernon city limits.

    • City zoning is codified in Mount Vernon Municipal Code Title 17.
    “Chapter 17.09 DISTRICTS ESTABLISHED – ZONING MAP (§ 17.09.010 – § 17.09.080)”
  • Zoning districtsPublished (with conditions)

    Zoning districts inside Mount Vernon city limits.

    • District location is determined by the zoning map under Chapter 17.09.
    • The Title 17 contents identify R-A Residential Agricultural and R-1 Single-Family Detached Residential districts among the published districts.
    “Chapter 17.12 R-A RESIDENTIAL AGRICULTURAL DISTRICT (§ 17.12.010 – § 17.12.090) [...] Chapter 17.15 R-1 SINGLE-FAMILY DETACHED RESIDENTIAL DISTRICT (§ 17.15.010 – § 17.15.120)”
  • Off-grid sanitationLimited

    Privies, septic tanks, cesspools, and new septic systems inside Mount Vernon city limits.

    • Privies, septic tanks, and cesspools are prohibited.
    • New septic systems are addressed only in limited cases as an interim measure.
    “§ 13.08.030 Privies, septic tanks and cesspools prohibited. [...] § 13.08.045 Construction of new septic systems provided in limited cases as interim measure.”
  • Subdividing landRegulated (with conditions)

    Land divisions and preliminary plats inside Mount Vernon city limits.

    • The city code contains a subdivision title and a preliminary-plat approval and procedure section.
    “§ 16.08.020 Authority to approve and procedure.”
  • Permit processPublished (with conditions)

    Land-use permit applications inside Mount Vernon city limits.

    • The detailed classifications, submittals, review process, time frames, and appeal provisions must be determined under Chapter 14.05.
    “§ 14.05.070 Summary of permit processes.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Mount Vernon or Skagit County directly.

  • Owner-builder exemption — Owner-built residential construction inside Mount Vernon city limits.
  • Inspections — Building work inside Mount Vernon city limits.
  • Certificate of occupancy — Occupancy of buildings inside Mount Vernon city limits.
  • Minimum dwelling size — R-1 Single-Family Detached Residential District inside Mount Vernon city limits.
  • Minimum lot size — R-1 Single-Family Detached Residential District inside Mount Vernon city limits.
17 more unanswered
  • Setbacks
  • Lot coverage
  • Building height
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Accessory dwellings
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Well permit
  • Agricultural exemption
  • Driveway access
  • Building in a floodplain
  • Short-term rentals
  • Permit fees

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 Mount Vernon publishes no rule on the point, not that none exists. Skagit County’s page lists the county offices to call.

Off-grid gear

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

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