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Building Permit Glossary

Nonconforming

A lawful use or structure that no longer meets current code requirements.

Site & zoningExisting conditionsSpecial approvals

Applies to

Older buildings · Existing uses · Structures within current setbacks · Lots that predate current standards

Project example

An old garage inside today's setback may remain lawful, but replacing, enlarging, or changing it can trigger limits on expanding a nonconforming structure.

Also called

legal nonconforminggrandfathered

Where this term shows up in permit work and how it affects the project

Legal nonconforming status can preserve an existing condition without allowing every alteration; the project must establish history and follow local continuation, damage, and expansion rules.

If this term appears in a form, plan comment, or local ordinance, start with the building permit guide, compare it against the zoning permit guide, then use the permit guide directory to find the right local path.

Why it matters for approval

Why nonconforming matters in a permit file

Nonconforming describes a lawful lot, structure, or use that does not meet a later zoning rule. Its continued existence may be protected, but reconstruction, expansion, change, abandonment, or damage is governed by detailed local provisions and often requires proof of legal status.

Where it appears in the permit process

  1. Status research

    Historic permits, ordinances, aerials, assessor records, surveys, and occupancy evidence are reviewed to establish when and how the condition became lawful.

  2. Project classification

    Staff determines whether the proposal maintains, repairs, alters, enlarges, replaces, resumes, or changes the nonconformity.

  3. Zoning determination

    The ordinance establishes administrative allowances, limits, required relief, damage thresholds, and discontinuance or abandonment rules.

  4. Permit conditions

    Approved dimensions, uses, restoration limits, timelines, and evidence become part of the building or zoning permit record.

What you may need

  • Current survey and description of the nonconforming condition
  • Historic permits, certificates, plans, photographs, and dated records
  • Ordinance sections for continuation, alteration, damage, and abandonment
  • Proposed plans that distinguish existing, removed, repaired, and enlarged work
  • Written zoning determination or special-approval application when required

Where to get it or verify it

  • Use municipal permit and zoning records plus dated written evidence; current appearance alone does not prove legality.
  • Ask zoning staff to identify whether the issue is a nonconforming lot, structure, use, or combination.
  • Use legal or planning professionals when vested rights, abandonment, enforcement history, or high-value redevelopment is involved.

Common mistakes that create comments or delays

  • Calling unpermitted work legally nonconforming
  • Assuming the right to remain includes the right to expand
  • Demolishing or damaging the feature before documenting its protected status
  • Failing to distinguish a nonconforming use from a nonconforming structure

What to do next

  1. Document what exists, when it was established, and under which approval.
  2. Classify the nonconformity and the exact proposed change.
  3. Obtain a written path before demolition, abandonment, or final design.
  4. Keep the approved limits visible in drawings, contracts, construction, and closeout.

Related permit paths

Related permit terms

Apply the term

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Permitech connects permit language to the responsible office, project requirements, required documents, and filing sequence.