Listed below are key concepts that are essential to understanding zoning. At the end of the guide is a glossary with a complete list of land use terms.

What is included on a lot?

Principal structure The building used for the principal land use; typically the largest structure on the lot. For instance, the house on a residential lot.

Accessory structures Any non-principal structures on the lot. For instance, a tool shed or garage on a residential lot.

Yards The required open spaces on the lot.

Buffer zone Areas that may be required to separate incompatible uses. A factory may be required to place buffer zones between it and nearby houses.

What is regulated?

Use regulations A key function of traditional Euclidian zoning is to regulate the uses of the structures. Most zoning codes list specific allowed uses; any use not listed is not allowed.

Physical regulations The size and configuration of structures on a lot.

Who can regulate?

Federal government The federal government regulates private land when it is adjacent to federal land or if the use of the land affects federal land. For example, the federal government can regulate land near Air Force bases and federal waterways.

States States have the most zoning powers. Regulations are allowed any time they meet the goals of the state under its police power authority.

Local governments Counties and local governments are only allowed to exercise the powers granted them by the states, as political subdivisions. Most large cities have home rule powers which grant them more power over their own affairs.

How is land regulated?

Zoning Regulations that control the size, shape and use of structures.

Taxes Governments can impose taxes that achieve regulatory purposes if there is also a fiscal purpose. For example, taxes can be imposed on specified uses of land. Impact fees are taxes that are paid to compensate the government for the burdens imposed by a development.

Takings Governments have the power of eminent domain, or the power to seize land for public purposes. This power is usually exercised to acquire land for public facilities, roads, schools, etc. Governments must pay "fair market value," as determined by a court, for land that is seized. No payments are required, though, when governments or private landowners' actions reduce or increase the value of another person's land.

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