Zoning, building permits and septic rules in Lynden, Washington

Lynden’s own rules

• Building permitRequired

  Buildings inside Lynden city

  • Exemption for one-story detached accessory buildings used as tool and storage sheds, playhouses and similar uses with floor area not over 120 sq ft

  permit threshold for accessory buildings: > 120 sq ft

  “(A permit is required for any building that is more than one hundred twenty square feet of floor area.)”

• Building code adoptedAdopted

  Residential construction inside Lynden city

  • Future amendments adopted automatically upon adoption by the State Building Code Council
  • One-story detached accessory buildings of 120 sq ft or less are exempt from a building permit

  “The city adopts the International Residential Code, published by the International Code Council, as the residential code of the city”

• Local zoningPresent

  Land inside Lynden city limits

  “The following table and text provides regulations for height, area, setback and bulk requirements:”

• Minimum lot sizeSpecified

  A-1 Agricultural zone inside Lynden city

  minimum parcel size: >= 20 acres

  “Minimum parcel size: twenty acres; 2. Maximum height of buildings: thirty feet;”

• SetbacksSpecified

  A-1 Agricultural zone inside Lynden city

  • Measured to building foundation; eaves and bay windows may encroach max two feet
  • State highways: 100 feet from centerline

  street setback (non-state highway): >= 20 feet · side setback: >= 10 feet · rear setback: >= 35 feet

  “3. yard setbacks for all buildings: a. from street, other than state highways: twenty feet, b. from state highways: one hundred feet from centerline, c. from side property line: ten feet, d. from rear property line: thirty-five feet.”

  One more reviewed finding on this topic

  • Specified — RS single-family zones inside Lynden city; columns are front, rear, side minimum, side total (feet)

    “RS-100 10,000 35% 32 2 20 30 7 22 RS-84 8,400 35% 32 2 15 30 7 22 RS-72 7,200 35% 32 2 15 30 7 17”

• Building heightSpecified

  A-1 Agricultural zone inside Lynden city

  maximum building height: <= 30 feet

  “2. maximum height of buildings: thirty feet;”

• Living in an RVLimited

  RV occupancy inside Lynden city

  • Permanent residential RV use only within mobile home parks (including CSR zone) with skirting and performance standards
  • RV camping is a primary use in the TR zone; parks need special property use approval
  • RV storage in RS zones limited

  “recreational vehicles and travel trailers may be permitted for permanent, residential use within mobile home parks including those located within the csr zone, provided that appropriate skirting and other performance standards are met”

• Camping on your landLimited

  Camping inside Lynden city

  • Unlawful in parks, streets, trails and public parking lots unless a special events permit applies
  • Camping permitted as a primary use in the TR zone

  “it shall be unlawful for any person to camp, or to occupy camp facilities or use camp paraphernalia for purposes of habitation, in the following areas, except as otherwise provided by ordinance or as permitted pursuant to section 12.40.080, the special events permit provision: 1. any park; 2. any street or trail; or 3. any publicly owned or maintained parking lot”

• Manufactured homesLimited

  Manufactured homes inside Lynden city (MH Manufactured Home zone)

  • Must meet federal and/or state requirements
  • Must meet the LMC 17.01.030 definition of a manufactured home

  “manufactured homes must meet or exceed all federal and/or state requirements. b. manufactured homes placed within the city of lynden must meet the definition of a manufactured home as defined in section 17.01.030 of the lynden municipal code.”

• Accessory dwellingsAllowed (with conditions)

  ADUs on lots with a detached single-family home in residential zones inside Lynden city

  • Max two ADUs per lot; not permitted with other housing types
  • Max 1,000 sq ft interior conditioned space
  • Dedicated on-site parking required
  • ADU covenant required; owner occupancy required only until January 1, 2026
  • Impact fees at 50% of primary unit

  max ADU size: <= 1000 sq ft · max ADUs per lot: <= 2 units

  “ADUs are permitted in all residential zones including planned residential developments provided that a maximum of two ADUs are allowed per lot as an accessory use to a single-family home.”

• Off-grid sanitationLimited

  Privies, septic tanks, cesspools inside Lynden city

  • Unlawful except as provided in chapter 13.12 (e.g. existing functioning OSS not yet required to connect)

  “Except as provided in this chapter, it is unlawful to construct or maintain any privy, privy vault, septic tank, cesspool or other facility”

• Mandatory utility hookupSewer (with conditions)

  Properties used for human occupancy inside Lynden city near a public sewer

  • Connection within ninety days after official notice
  • Properties with an existing functioning OSS need not connect until failure, pollution risk, or county health department finds replacement needed
  • Building permit code also requires connection if building is within 400 feet of an existing sewer line (LMC 15.02.050)

  distance to sewer: <= 300 feet (existing functioning OSS exempt until failure)

  “is required at his/her expense to install suitable toilet facilities therein, and to connect such facilities directly with the proper public sewer”

• Shed and accessory-building permit exemptionAvailable (with conditions)

  One-story detached accessory buildings inside Lynden city

  • Only tool and storage sheds, playhouses and similar uses
  • Floor area must not exceed 120 sq ft
  • Zoning rules still apply

  max floor area without permit: <= 120 sq ft

  “one-story detached accessory buildings used as tool and storage sheds, playhouses and similar uses, provided the floor area does not exceed one hundred twenty square feet, do not require a building permit.”

• Subdividing landRegulated (with conditions)

  Platting/subdivision inside Lynden city (LMC Title 18)

  • Details of Title 18 not opened

  “Street trees are required at the time of plat as outlined in Chapter 18.”

• Short-term rentalsLimited

  Short-term rentals inside Lynden city

  • Home occupation permit required in residential zones
  • Operator must reside on premises in detached housing
  • Only one guest group at a time in residential zones
  • State business license required
  • Pre-hosting inspection
  • Attached housing: RM-4 zone only, max 10% of units

  “b&b and str establishments located in residential zones require a home occupation permit”

• Permit feesVariable (with conditions)

  Residential building permit fees inside Lynden city

  • Set by city council resolution; the resolution itself was not opened

  “residential permit fees shall be as set forth by resolution of the city council.”

Still unanswered

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

• Owner-builder exemption — Owner-builder exemption inside Lynden city
• Inspections — Building inspections inside Lynden city
• Certificate of occupancy — Certificates of occupancy inside Lynden city
• Minimum dwelling size — Minimum dwelling size inside Lynden city
• Tiny homes — Tiny homes inside Lynden city

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.