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Nonconforming Uses, Structures, and Lots

This page provides information on local government regulation of nonconforming uses in Washington State, including relevant court decisions and examples of local ordinances.

Nonconforming uses involves the continued use of a property that, because of subsequent changes in regulations, is no longer an allowable use. It should not be confused with vested rights, which involves determining which land use statutes and ordinances apply to a pending application.


A nonconforming use is a use of property that was allowed under the zoning regulations at the time the use was established but which, because of subsequent changes in those regulations, is no longer a permitted use.

A nonconforming structure is a structure that complied with zoning and development regulations at the time it was built but which, because of subsequent changes to the zoning and/or development regulations, no longer fully complies with those regulations.

A nonconforming lot is one that, at the time of its establishment, met the minimum lots size requirements for the zone in which it is located but which, because of subsequent changes to the minimum lot size applicable to that zone, is now smaller than that minimum lot size.

State law does not regulate nonconforming uses, structures, or lots, so local jurisdictions are free, within certain constitutional limits, to establish their own standards for regulation of these nonconforming situations.

Nonconforming uses and structures are not illegal uses and structures; they are generally allowed to continue as is, subject to local restrictions. In Rhod-A-Zalea v. Snohomish County (1998), the state supreme court explained the basis for this treatment of nonconforming uses:

The theory of the zoning ordinance is that the nonconforming use is detrimental to some of those public interests (health, safety, morals or welfare) which justify the invoking of the police power. Although found to be detrimental to important public interests, nonconforming uses are allowed to continue based on the belief that it would be unfair and perhaps unconstitutional to require an immediate cessation of a nonconforming use.

Local restrictions typically prohibit expansion of nonconforming uses and structures. Nonconforming uses usually lose their legal status under local regulations if they are discontinued for a particular period of time, such as six months or a year. Nonconforming structures typically lose their legal status if they are destroyed, such as by fire, in whole or in part.

Uses that become nonconforming as a result of changes in zoning regulations are still subject to reasonable regulations under a city or county's police power to protect the public health, safety, and welfare that are enacted subsequent to the use being established. See Rhod-A-Zalea v. Snohomish County (1998) at 8-9. In that decision, the court held that a company that had the right to mine peat as a nonconforming use was subject to a later-enacted local building regulation that required a grading permit excavate or fill the property.

Zoning ordinances may provide for the termination of nonconforming uses by reasonable amortization provisions. Such amortization provisions, which allow for the continued operation of the use for a period of time deemed sufficient to recoup the investment put into the use, are commonly applied to restrictions or prohibitions imposed on billboards.

Property owners are generally allowed to build on their nonconforming lots, although they typically must meet setbacks applicable to that zone, unless a variance from such setbacks is applied for and can be granted under the adopted criteria for variance approval. Denial of the ability to build on a nonconforming lot could, in some cases, constitute a "taking" under the federal and state constitutions. Where a property owner owns two adjacent and undeveloped nonconforming lots, some jurisdictions treat the two lots as one, conforming lot.

Examples of Local Codes

Below is a selection of code examples related to nonconforming uses, structures, and lots:

Selected Court Decisions

The following list of case summaries highlights key court decisions on nonconforming uses issues affecting local governments. This is not intended to be a comprehensive list of all cases.

County correctly denied a permit application requesting rental of two short term rentals be approved as a legal nonconforming use, as the use was not legal and the property owner did not have a vested right to continue its unlawful, nonconforming use.

Icicle/Bunk, LLC v. Chelan County (2023) – The case involved a county’s code regulating short term rentals (STR). In 2007, the county adopted a code requiring the owner occupy either the primary unit or the accessory unit as their permanent residence and, in 2021, the county modified its code to prohibit more than one short-term rental per parcel. Since 2006, Icicle had rented out two STRs on their property, without residing on the property. In 2021, Icicle submitted a permit application to continue operating two STRs as a nonconforming use. The permit was denied and the hearing examiner affirmed the denial.

On appeal, Icicle argued that its use of the property for two STRs is a legal nonconforming use that is allowed to continue even after the 2021 code modification. The court stated that a nonconforming use is a use which “lawfully existed prior to enactment of a zoning ordinance, and which is maintained after the effective date of the ordinance, although it does not comply with the zoning restrictions applicable to the district in which it is situated.” In other words, “a nonconforming use” is a ‘vested’ property right that has protections; but it’s only a right not to have the use immediately terminated in the face of a zoning ordinance which prohibits the use. The court held Icicle’s proposed permit application did not meet the requirements for a legally nonconforming use, largely because the property owner did not occupy either the primary unit or the accessory unit as their permanent resident. In addition, the court held that requiring Icicle reduce the number of buildings used for STRs is a valid regulation and does not constitute a termination of use.

Establishment of nonconforming use is a fact-specific analysis

Seven Hills LLC v. Chelan County, 198 Wn.2d 371 (2021) – The state supreme court held that Seven Hills LLC established a nonconforming use when it obtained a license from the Liquor and Cannabis Board (LCB) and had invested $750,000 in site improvements, licensing, and permitting toward a cannabis production and processing facility, even though the LCB license was issued after the county issued a moratorium on the siting of new cannabis production and processing facilities. The majority held that the moratorium did not change the underlying zoning. Permanent county regulations prohibiting cannabis production and processing facilities were not adopted until after Seven Hills obtained its LCB license, land use permits, and made significant investments. The dissent argued that the majority failed to give proper effect to the county’s moratorium.

Use had not been established prior to zoning change so to establish a legal nonconforming use

King County, DDES v. King County, 177 Wash.2d 636 (2014) – The materials processing component of landowner's materials processing facility had not begun at time of amendment of zoning regulation, and therefore landowner had not established use of the property in conformance with previous ordinance. There was therefore no established lawful nonconforming use. Landowner had obtained rights to the land, stored some materials on the property, and expressed an intent to take further action toward a recycling operation, but had not commenced actual recycling.

Trespasser cannot establish nonconforming use

McMilian v. King County, 161 Wn. App. 581 (2011) – The court held that a trespasser onto land cannot lawfully establish a valid nonconforming use, which use in this case was an auto wrecking yard that spilled over from adjacent property. The court remanded the case back to the superior court for a determination of whether the use of the property at issue was permissive, such that there had been no trespass.

Doctrine of diminishing asset

City of University Place v. McGuire, 144 Wn.2d 640 (2001) – The state supreme court adopted the doctrine of diminishing asset and determined that the previous owner's legal nonconforming mining use extended to the boundaries of the 80-acre parcel of land, and vested in the developer, the successor in interest. The court explained that this doctrine "can be seen as either an exception to the general principle that a nonconforming use will be restricted to its original site or as a substantive adaptation of the nonconforming use doctrine to recognize the realities of extractive industries." The court concluded that the city had not established an act or omission that would prove that that nonconforming use had been abandoned. That the parcel had not yet been mined and was sold without mention of mining was not conclusive.

Change to another kind of use 

Open Door Baptist Church v. Clark County, 140 Wn.2d 143 (2000) – Where a nonconforming use is in existence at the time that a zoning ordinance is enacted and is thus allowed to continue, it "'cannot be changed into some other kind of a nonconforming use.'" So, even though the property in question in this case was originally used as a church, it had been an art school for 12 years prior to church's purchase of it in 1990. Whatever original nonconforming use status it may have once enjoyed could not be passed along to the church.

Subject to later enacted police power regulation

Rhod-A-Zalea v. Snohomish County, 136 Wn.2d 1 (1998) – Mining operation's valid existing nonconforming use was subject to county's later enacted police power regulation that imposed a requirement that the operation obtain a grading permit before conducting its ongoing excavation and fill activities.

Compliance with health code regulations

Christianson v. Snohomish Health Dist., 133 Wn.2d 647 (1997) – The county health district denied construction clearance to increase the size of a cabin, on the basis that the cabin's onsite septic system was inadequate to handle any additional use. The onsite septic system had recently been renovated and had been approved by the health district as an acceptable substandard system for the existing, unimproved cabin, but a district resolution prohibited the construction of additions to buildings with substandard septic systems. The court held that requiring the plaintiffs to comply with minimum health code regulations when building an addition is a reasonable means to protect public health and water quality.

Grandfathering under building code 

Sumner v. First Baptist Church, 97 Wn.2d 1 (1982) – A church-operated school is entitled to the benefit of the "grandfather clause" of the building code and the "nonconforming use" provision of the zoning ordinance. The Uniform Building Code provided that "Buildings in existence at the time of the passage of this Code may have their existing use or occupancy continued, if such use or occupancy was legal at the time of the passage of this Code, provided such continued use is not dangerous to life." There was no attempt to show, nor any finding, that continued use of the building as a church would be dangerous to life.

No enlargement of nonconforming use 

Keller v. Bellingham, 92 Wn.2d 726 (1979) – The court held that a corporation's improvements to its plant that increased production did not enlarge a nonconforming use in violation of a city's ordinance. The city's nonconforming use ordinance did not specifically proscribe intensification of nonconforming uses.

Termination period

Northend Cinema v. Seattle, 90 Wn.2d 709 (1978) – Theater owners challenged the validity of ordinances that prohibited them from showing adult movies in their present locations and that terminated all nonconforming uses within 90 days. A balancing test was adopted to determine the reasonableness of the termination period, that is, whether the harm or hardship to the user outweighs the benefit to the public to be gained from termination of the use. This test is applied on a case-by-case basis, looking to the circumstances of each nonconforming user. The court in this case found that the period for termination of the nonconforming uses was reasonable.

Establishment of use 

Anderson v. Island County, 81 Wn.2d 312 (1972) – The use of property must be established prior to the adoption of the zoning ordinance to qualify as a nonconforming use thereafter. The mere purchase of property and the occupying of it are not sufficient factors to establish an existing nonconforming use.

Expansion of nonconforming use

Bartz v. Bd. of Adjustment, 80 Wn.2d 209 (1972) – A board of adjustment had authority to approve an application to construct a building at an auto wrecking yard even though the application sought an extension of a pre-existing non-conforming use, because there was no prohibition in the zoning ordinance against the extension or expansion of a nonconforming use and because the expansion would improve the unsightly conditions at the yard.

Evidence supporting decision

First Pioneer Trading Co. v. Pierce County, 146 Wn. App. 606 (2008), review denied, 165 Wn.2d 1053 (2009) – The court upheld a hearing officer's decision denying a property owner's claim of a legal, nonconforming use of its property, because the decision was supported by substantial evidence, including aerial photographs provided by a county and testimony from neighbors verifying that the owner's business was not located on the property prior to the change in zoning laws.

Procedure to continue nonconforming use

City of Des Moines v. Gray Businesses, 130 Wn. App. 600 (2005), review denied, 158 Wn.2d 1024 (2006) – The owner of a mobile home park did not comply with an ordinance requiring that the owners of nonconforming uses file a site plan to legally continue their nonconforming uses, and the city notified the owner that the use was no longer allowable. The court of appeals held that the city's ordinance was a valid regulation, not a taking, because the "right" to use the property for a particular use is not a fundamental attribute of ownership. Rather, it is a contingent right that is dependent upon state law and local regulations such as business license requirements and zoning.

Recommended Resources

Last Modified: January 25, 2024