It is a basic tenet of traditional zoning that different uses are assigned to different zoning districts. In a typical zoning ordinance, each zoning district will have a list of land uses that are allowed within that district, either as permitted use, or as a special exception (conditional or special) use.
What happens, then, when a desired use is not listed at all; in other words, when a use is an unlisted use? The answer is deceptively simple: an unlisted use is not allowed in that zoning district. In practice, however there are several exceptions to this general rule, as well as a few allowable (and unallowable) remedies.
Some zoning ordinances include the phrase “or similar” in their list of allowed uses or special exception uses. If this language is present, then a determination needs to be made if the unlisted use is similar enough to a listed use or uses to be allowed in the particular zoning district. The ordinance most often designates the Zoning Board of Adjustment to make that determination. In some states that determination might be made by the planning commission or the zoning administrator, depending on the respective state's enabling statute
If there is no “or similar” language in the ordinance, or if the desired use has been determined not similar, an unlisted use still can be added to a zoning district by ordinance text amendment, using the same amendment process set out for other zoning amendments. Such an amendment is subject to normal standards of being consistent with the adopted master plan, and appropriate for the property in question, as well as for surrounding uses. Some states might also allow for this situation to be handled as a use variance, which is a decision that goes before the Zoning Board of Adjustment.
The all-too-common practice of treating an unlisted use as if it were a special exception (special use, conditional use,) even when not included in the zoning district list of special exceptions, is simply not a lawful practice, and should be scrupulously avoided.
Mary Ann Heidemann, Michigan State University
