Nonconforming Parcels, Uses, & Structures

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When a parcel, use, or structure is described as “nonconforming”, it means that the parcel, use, or structure was established before the adoption of an applicable regulation, and therefore can continue to remain, be repaired, and be modified to a certain extent, without complying with that regulation.


This illustration represents what could be added to an existing nonconforming structure that protrudes into the side yard, as described below.

Nonconforming Structure
Ordinary repairs and maintenance of nonconforming structures is allowed. If a nonconforming structure is damaged by fire, earthquake, or other natural calamity, the nonconforming structure may be repaired.  The building permit for the restoration must be submitted within 18 months following the damage.

Nonconforming Residential Structure:

  • With a Conforming Residential Use – Legally nonconforming structures may be replaced, enlarged, moved, or modified; provided, such replacement, enlargement, movement, or modification complies with the setback, height, and location requirements of the zoning district in which the site is located, and with the requirements of TMC Chapter 13.11.
  • With a Nonconforming Residential Use – Expansion cannot increase the number of dwelling units or reduce existing lot area or off-street parking. Any expansion, including the construction of accessory buildings, shall be limited to compliance with the regulations of the zoning district in which the subject site is located.
  • Additions onto Nonconforming Residential Structures:
    • Additions may extend into a required front, side, or rear yard setback when the existing dwelling is already legally nonconforming to that setback requirement.
    • The nonconforming portion shall be at least 60 percent of the total width of the respective wall of the structure prior to the addition and any other additions added since May 18, 1953.
    • Additions may extend up to the height limit of the zoning district and extend into the required front, side and/or rear yard setback as follows:
      • Front and rear yard setbacks: Additions may extend five feet into the required setback or to the extent of the setback line formed by the nonconforming portion, whichever is less.
      • Side yard setbacks: Additions may extend into the required side yard setback up to the setback line formed by the nonconforming wall, except in no case shall the addition be closer than 3 feet from the side property line. The size of the addition shall be limited to an additional wall surface area within the required side setback area of no more than 200 square feet.

Nonconforming Use
Legally nonconforming uses may continue unchanged.  If the structure is damaged by fire, earthquake, or other natural calamity, such nonconforming use may be resumed once the building is repaired. The building permit for the restoration must be submitted within 18 months following the damage.

  • Allowed Changes and Expansions to a Nonconforming Use – An existing nonconforming use may be expanded to occupy a larger portion of its existing building, provided it does not increase the cumulative generation of vehicle trips or the number of parking spaces that would be required by more than 10 percent (Multiple changes or expansions that would, in the aggregate, exceed the 10 percent requirement as calculated for the initial request are not allowed.); increase noise such that it exceeds maximum noise levels identified in WAC 173-60; result in substantial additional light or glare perceptible at the boundary lines of the subject property; increase outdoor storage of goods or materials; or increase in the hours of operation.
  • Abandonment – When a nonconforming use is vacated or abandoned for 12 consecutive months or for 18 months during any three-year period, the nonconforming use rights shall be deemed extinguished. Once nonconforming use rights are extinguished any new use must be an allowed use in the applicable zoning district.

Nonconforming Structure with Nonconforming Commercial or Industrial Use

  • A legal nonconforming structure, that is also nonconforming as to use, may only be expanded and/or modified in the following cases:
    • Ordinary repairs and maintenance, including painting, repair, or replacement of wall surfacing materials and the repair or replacement of fixtures, wiring, and plumbing are permitted; provided, such repair or maintenance will not result in noise exceeding levels identified in WAC 173-60, light, or glare at the boundary lines of the subject property.
    • The enlargement or modification is required for safety upon order of the City, or otherwise required by law to make the structure conform to any applicable provisions of law.
    • Such enlargement and/or modification does not result in an intensification of the use as addressed by TMC 13.06.010.L.5.c.
    • Such enlargement and/or modification complies with the requirements of TMC Chapter 13.11.

Nonconforming Parcel
An existing, legal nonconforming parcel, which does not conform to the minimum lot area, minimum lot width, and/or minimum lot depth requirements may be developed subject to all other development standards, use restrictions, and other applicable requirements.  Parcel modifications, such as boundary line adjustments, property combinations, segregations, and short and long plats shall be allowed, without need for a variance, to modify a nonconforming parcel, as long as such actions would make the nonconforming parcel(s) more conforming to the existing requirements and would not create any new or make greater any existing nonconformities.

Critical Areas
Pre-existing uses or structures located within a wetland, stream or their associated buffers that were lawfully permitted prior to adoption of the TMC Chapter 13.11, Critical Areas Preservation Ordinance (CAPO), but were not in compliance with the CAPO, shall be subject to the applicable provisions of this section and TMC Sections 13.11.140 and 13.11.160.

Nonconforming Signs
Nonconforming sign cannot be expanded or altered in a way which would increase the nonconformity, or be structurally altered to prolong its useful life or moved to another location where it would remain nonconforming.   However, a legally nonconforming on-premises sign may be altered if the degree of nonconformity for height and sign area is decreased by 25%.  Any sign which is discontinued for a period of 90 consecutive days shall be presumed to be abandoned.  Any nonconforming sign that is damaged or destroyed to the extent of one-half of its replacement cost new shall be terminated and shall not be restored.

Applicable Regulations

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