In order to classify, segregate, and regulate the uses of land, buildings, and structures, the town is divided into the following use districts:
R - Residential zones are intended to create a living environment of optimum standards for single-family dwellings. They are further intended to encourage development of higher degrees of density. This district will provide for the development of single-family detached dwellings, accessory dwelling units (ADU), duplex, triplex, and four-plex, and for such accessory uses as are related, incidental and not detrimental to the residential environment.
A - The airport land use district is to ensure a regulatory means of facilitating airport-compatible land uses at the Concrete Municipal Airport.
CL - The intent and objective of this classification and its application is to set apart that portion of the town which forms the financial, commercial, light industrial, governmental, professional, and cultural activities all of which have common or similar performance standards in that they represent types of enterprises involving the rendering of services, or on-premises retail or wholesale activities. This district is intended as a sanctuary for light, clean businesses usually of a light manufacturing or storage nature, or on-premises retail activities. These businesses have very little process visibility. They should generate little air or water pollution, noise or objectionable odors. Outdoor storage is limited. Wholesale and retail sales are permitted.
TC - To preserve the heritage of the existing town center zoning district of the town and provide for its vitality. The intent and objective of this classification and its application of the design guidelines in CMC § 19.36.055(3) is to promote the historic character of the town center and set apart as that portion of the town which forms the historic center for financial, commercial, governmental, professional, and cultural activities, all of which have common or similar performance and design elements in that they represent types of enterprises involving the rendering of services, both professional or to the person, or on-premises retail activities. This zone encourages leisure shopping and provides amenities and historic design features conducive to attracting pedestrian shoppers.
I - The intent and objective of this classification and its application is to provide for the location of and grouping of enterprises which may involve some on-premises retail service but with outside activities and display or fabrication, assembling, and service features. The I - industrial zone is also intended to provide for general manufacturing and processing and grouping of industrial enterprises which possess common or similar characteristics and performance standards involving manufacturing, assembling, fabrication and processing, bulk handling of products, large amounts of storage and warehousing, outdoor storage, processing and other related uses. The uses enumerated in this classification are considered as having common or similar performance standards in that they are heavier in type than those uses permitted in the more restrictive commercial classifications.
P - The public lands district is intended to provide for the availability of public land for the placement of public buildings, facilities, parks, open space, habitat conservation areas, recreation and semi-public uses that will enhance and contribute to the quality of life and services of the community.
OS - It is the intent of this chapter to encourage desirable and appropriate land uses in areas of the town which by reason of location, soil, topographic or flooding characteristics, public ownership, wetlands, wildlife habitat, or values to the community for scenic, recreation, agriculture, forest, or open space, are not suited to intensive land development patterns as determined by the comprehensive plan and may require specific management or development techniques. Use of this district may also allow for special assessment as open space under the provisions of Skagit County's open space taxation program. This district shall not, however, be construed as guaranteeing open space land valuation. To secure such assessment, application must be made to the county assessor as set forth in Skagit County law.
(Ord. 426 § 10.09.010, 1998; Ord. 464 § 10.09.010, 2001; Ord. 900 § 2 (Att. A (3)))
All lands not classified according to the aforementioned classifications on the official zoning maps, and all lands, if any, of the town not shown on officially adopted zoning maps, shall be considered unclassified and, pending future classification, shall be subject to other restrictions and regulations of the Residential district.
(Ord. 426 § 10.09.020, 1998; Ord. 464 § 10.09.020, 2001)
The boundaries of such use districts as are shown upon any zoning map adopted by this title, or amendments thereto, are adopted and approved and the regulations of this title governing the uses of land, buildings and structures, the height of buildings and structures, the sizes of yards about buildings and structures, and other matters as set forth in this title are hereby established and declared to be in effect upon all land included-within the boundaries of each and every use district shown upon each zoning map.
(Ord. 426 § 10.09.030, 1998; Ord. 464 § 10.09.030, 2001)
The boundaries of use districts shall be determined and defined or redefined from time to time, by the adoption of zoning maps covering the town and showing the geographical area and location of said use districts. Each zoning map shall be, upon its final adoption, a part of the zoning ordinance codified in this title, and said map, and all notations, references and other information shown thereon, thereafter shall be as much a part of this title as though all matters and information set forth on said map were fully described in this title.
(Ord. 426 § 10.09.040, 1998; Ord. 464 § 10.09.040, 2001)
When uncertainty exists as to the boundaries of any use district shown on zoning maps, the following rules of construction shall apply:
(1) 
Where district boundaries are indicated as approximately following the centerline of streets, alleys or highways, the actual centerline shall be construed to be the boundary.
(2) 
Where district boundaries are indicated as running approximately parallel to the centerline of a street, the boundary line shall be construed to be parallel to the centerline of the street.
(3) 
Where district boundaries are indicated on such map as approximately following the lot or tract lines, the actual lot or tract lines shall be construed to be the boundary of such use district.
(4) 
Where a district boundary on such zoning map divides a tract in nonsubdivided property, the location of such use district boundary, unless the same is indicated by dimensions thereon, shall be determined by use of the scale appearing on such zoning map.
(5) 
Where a public street or alley is officially vacated or abandoned, the regulations applicable to the abutting property to which the vacated portion shall revert shall apply to such vacated or abandoned street or alley.
(6) 
Where district boundaries are indicated on such map as approximately following the baseline of a steep slope that forms a natural barrier this baseline shall be construed to be the boundary of such use district.
(7) 
In case uncertainty exists which cannot be determined by application of the foregoing rules, the town council shall determine, the location of such use district boundaries.
(Ord. 426 § 10.09.050, 1998; Ord. 464 § 10.09.050, 2001)
Except as otherwise provided in this title:
(1) 
No building or structure shall be erected and no existing building or structure shall be moved, altered, added to or enlarged, nor shall any land, building structure or premises be used, designed or intended to be used for any purpose or in any manner other than a use listed in this title or amendments thereto or permitted in the use district in which such land, building, structure or premises is located.
(2) 
No building or structure shall be erected, nor shall any building or structure be moved, altered, enlarged or rebuilt, nor shall any open spaces surrounding any building or structure be encroached upon or reduced in any manner, except in conformity with the building site requirements and the area, yard and height regulations established by this title or amendments thereto for the use district in which such building or structure is located.
(3) 
No yard or other open spaces provided about any building or structure for the purpose of complying with the regulations of this title or amendments thereto shall be considered as providing a yard or open space for any other building or structure.
(Ord. 426 § 10.09.060, 1998; Ord. 464 § 10.09.060, 2001)