Part One Summary:

Nonconforming uses, the natural by-products of zoning, are created when zoning rules change over time and the old uses are grandfathered in under the original approvals.

How the grandfathered uses are treated, how long they survive, and how much they are allowed to change are all decided, in the first instance, by the planning commission. This article and part two discusses the governing rules.

Know the Basics

The goal of most nonconforming use ordinances is to prevent expansion and encourage eventual termination of the use while, at the same time, protecting investments made in reliance on the original zoning. Nonconformities come in two types: activities on the property and the physical condition of the lot or structures. Both are referred to as nonconforming uses; the rules governing the two types often differ, and they pose different planning problems.

Part Two Summary:

Nonconforming use ordinances seek to encourage replacement of nonconforming buildings and uses over time, preferably through natural market forces.

Termination and Amortization

Nonconforming use ordinances seek to encourage replacement of nonconforming buildings and uses over time, preferably through natural market forces. Most ordinances prohibit reconstruction of structures that are destroyed or damaged by more than a specified percentage, usually 50 percent. This rule can be unpopular and hard to enforce, especially after natural disasters. However, it serves an important public purpose, such as making sure homes are rebuilt to current safety standards after a major flood event. Local governments should assist owners in meeting the new rules; many owners may have been unaware that their homes were nonconforming before the disaster. Destruction or replacement is commonly used to terminate nonconforming structures. Nonconforming lots are almost impossible to correct, unless the same owner acquires an adjacent parcel. If allowed by state law, many communities provide for automatic merger of substandard lots when they come into common ownership as a solution.