Buying Property With a Nonconforming Use: A Due Diligence Guide

A legal nonconforming use is one that was lawful when it began but would not be allowed under today's zoning. It can usually continue, and a sale does not end it. But the right is fragile: it can be lost if the use stops for too long, if the building is badly damaged, or if the use is expanded or changed without approval. If the value of a property depends on a grandfathered use, the questions below decide whether you are buying an asset or a liability. Every code answers them differently, so confirm each one in the local code and, where possible, in writing from the city.

For the basic concept, see what is a nonconforming use.

1. Is the use legal nonconforming, or just illegal?

A use that never had the required approvals is not grandfathered, however long it has operated. Detroit and Chicago put the burden of proving legal nonconforming status on the owner, and Miami's code requires that all required permits were issued when the use began.

Collect the evidence before you close:

• building permits and certificates of occupancy, with dates
• business licenses and leases showing when the use started and that it continued
• the zoning in effect when the use began, and the change that made it nonconforming
• utility bills or other records showing no long gap in operation

Then ask the city to confirm it in writing, if it will. Practices differ:

• New York City: the Department of Buildings issues a Letter of No Objection for older buildings. For a nonconforming use, it may ask for leases or utility bills showing the use did not stop for more than two years. The fee is $25 for one- to three-family buildings and $130 for others, and it takes about three weeks.
• Austin: a Development Compliance Letter confirms development matched approved plans, that there are no zoning code violations, and the ability to rebuild after a loss.
• Atlanta: a separate non-conforming zoning verification letter costs $300 and requires notarized affidavits from people who know the property.
• Phoenix: the standard $350 zoning verification letter states that it does not certify non-conforming status.

A basic zoning letter usually confirms only the district. See how to get a zoning verification letter.

2. How long can it sit vacant, and can it be rebuilt?

These two clocks cause most lost rights. A vacancy during the sale, a long renovation, or a lapsed license can run out the first. A fire can trigger the second.

The measures differ as much as the numbers: cost versus value, assessed versus replacement value, floor area versus dollars. Read the exact test in your code.

3. What can you change?

Most codes limit growth and change:

• Expansion: Detroit treats any added floor area as an expansion and requires a Board of Zoning Appeals hearing. Los Angeles does not let a nonconforming use expand into other parts of the building. Miami bars enlarging or rebuilding a structure with a nonconforming use except to make it conforming.
• Improvements: Austin lets some nonconforming uses be improved only up to 20 percent of the structure's value, depending on the use's group.
• Switching uses: New York City and Detroit allow a change to another nonconforming use only under their rules, and Detroit requires the new use to be less harmful than the old one. In Detroit, once a nonconforming use is converted to a conforming one, it cannot go back.
• Ownership and tenants: Chicago, Detroit, Miami, and New York City say a change of owner or tenant does not by itself affect status.

If the business plan needs more space, a variance or a rezoning may be the real route.

4. Is there an end date?

Some codes set deadlines for certain nonconforming uses, called amortization:

• Austin: some uses that occur outside a structure, or in a structure valued under $10,000, must end 10 years after becoming nonconforming.
• Miami: nonconforming uses may continue for 20 years from when they became nonconforming, then need a City Commission extension.
• Los Angeles: certain commercial and manufacturing uses in agricultural and residential zones have five years.

State law can limit this. Since 2023, Texas requires a city that forces a nonconforming use to stop to pay the owner's costs and lost market value, or let the use continue until those are recovered. That protection does not apply to a use intentionally abandoned for at least six months. Arizona's statute protects the continued use of existing property and allows cities to buy out nonconforming uses.

5. Financing and insurance

Lenders will often finance a legal nonconforming property, with conditions:

• Fannie Mae (one to four units) will buy a loan on a legal nonconforming use if the appraisal reflects any adverse effect on value and marketability.
• Fannie Mae Multifamily requires the lender to confirm the share of damage at which the city would bar rebuilding to the prior use, and will not take the loan if that threshold is below 50 percent.
• Freddie Mac Multifamily wants a statement from the zoning authority that the property can be rebuilt to its pre-damage size, density, and configuration, or legislation or a variance showing the same. Failing that, it needs the zoning authority's damage threshold, measured against market, replacement, or appraised value rather than tax-assessed value, plus the lender's analysis of the casualty risk.
• FHA appraisers must report the property as legal non-conforming and state whether it may be legally rebuilt if destroyed.

Fannie Mae and Freddie Mac Multifamily also require ordinance or law insurance for nonconforming properties. It covers the loss of the undamaged part of a building that the law will not let you keep (Coverage A), demolition and debris removal (B), and the extra cost of rebuilding to current code (C). Ask your insurer early, because the amount required depends on the city's damage threshold.

A short checklist

1. Get the city's written confirmation of legal nonconforming status, or the evidence to prove it.
2. Confirm the use has not stopped, and keep it operating, licensed, and leased through closing.
3. Read the code's discontinuance, damage, expansion, and amortization rules.
4. Ask the lender what it needs and price ordinance or law insurance.
5. Model the property as if it had to become conforming after a casualty.

How to check a specific parcel

Confirm the current district and whether the existing use is permitted in it. In Plotzy, click the parcel to see its zoning designation and ask Zoning AI "Is this use permitted in this district, and how long can a nonconforming use be discontinued here?" for an answer with the code section cited. If the use is not permitted, you are looking at a nonconforming property and the steps above apply.

Frequently asked questions

Does a nonconforming use transfer to a new owner?

Generally yes. Several codes say a change of ownership or tenancy does not affect status. The risk is a gap in operation during the sale.

Can I rebuild a nonconforming building after a fire?

Only within the code's damage limit and deadline. Beyond the limit, the use or building usually must conform. Thresholds range from 50 percent to 90 percent in the codes above, measured in different ways.

Can I get a loan on a nonconforming property?

Often, yes, if the property is legal nonconforming and the lender's conditions on value, rebuilding, and insurance are met. An illegal use is a different matter.

Sources

The statutes, codes, and agency documents cited on this page were checked on October 20, 2026. Codes and lender guides change often, so confirm the current version before relying on any detail. This page is general information, not legal advice.

• City of Austin: Land Development Code, Chapter 25-2, Article 7 (Nonconforming Uses). Abandonment, damage, groups, improvement limits, and the 10-year rule.
• City of Austin: Zoning Verification. The Development Compliance Letter.
• City of Detroit: Code Chapter 50, Article XV (Nonconformities). Burden of proof, abandonment, damage, expansion, changes of use, and status on transfer.
• City of Miami: Miami 21 Code, Article 7. Section 7.2: nonconforming uses, discontinuance, restoration, alterations, and the 20-year limit.
• City of Chicago: Zoning Ordinance Chapter 17-15. Burden of proof, discontinuance, damage, expansion, and status on transfer.
• City of Los Angeles: Municipal Code Section 12.23. Discontinuance, restoration, expansion, changes of use, and amortization.
• NYC Department of City Planning: Zoning Resolution Sections 52-22, 52-31, 52-41, 52-531, and 52-61. Alterations, changes of use, enlargement, damage, and discontinuance.
• NYC Department of Buildings: Letter of No Objection application (rev. July 2024). Evidence, fees, and timing.
• City of Atlanta: Zoning Verification. The non-conforming zoning verification letter.
• City of Phoenix: Zoning Verification Letter process (rev. October 2, 2023). What the letter does not certify.
• Texas Legislature: Local Government Code Section 211.019. Remedies when a city requires a nonconforming use to stop.
• Arizona Legislature: A.R.S. 9-462.02. Continued use and acquisition of nonconforming uses.
• Fannie Mae Selling Guide B4-1.3-04. Legal nonconforming use in one- to four-unit appraisals.
• Fannie Mae Multifamily Guide, Section 301 and Section 501.02E. Destruction threshold rule and ordinance or law insurance.
• Freddie Mac Multifamily Guide, Chapter 8 and Chapter 31. Restoration statements and ordinance or law insurance. Both sections were revised on October 20, 2026, and this page reflects the revised text.
• HUD: FHA Single Family Housing Policy Handbook 4000.1 (August 2026). Section II.D.3.b.ii(C), zoning in FHA appraisals.
• California Department of Insurance: Small Business Guide to Commercial Insurance. What ordinance or law coverages A, B, and C pay for.