Plain-English definitions of zoning and land use terms. Written for developers, lenders, brokers, architects, and title companies who need to understand zoning quickly.
A secondary residential unit on the same parcel as a primary single-family home. ADUs can be attached (e.g., an in-law suite), detached (a backyard cottage), or converted from existing space (a garage conversion). Most states have enacted ADU preemption laws that override local zoning restrictions to allow ADUs by-right.
Converting an existing building to a new use — for example, turning a warehouse into loft apartments or an office building into condominiums. Adaptive reuse projects often require variances or conditional use permits if the new use differs from the building's original zoning classification.
An American Land Title Association / National Society of Professional Surveyors survey. ALTA surveys establish boundary lines, easements, encroachments, and improvements to a standard accepted by title insurers nationwide. Lenders require ALTA surveys for commercial real estate loans. A Zoning Assist report complements an ALTA survey by providing the zoning analysis needed for ALTA Table A Item 6 (zoning classification and setbacks).
Development that is permitted outright under current zoning without requiring discretionary approvals such as a variance, conditional use permit, or rezoning. By-right projects are approved administratively — the applicant meets the code requirements and the permit is issued. Lenders strongly prefer by-right entitlements because approval is more predictable.
A discretionary approval granted by a planning board or zoning hearing body that allows a use that is not permitted by-right but may be appropriate under specific conditions. CUPs are project-specific — they can be conditioned, modified, or revoked. They increase entitlement risk because approval is not guaranteed. Also called a Special Use Permit (SUP) or Special Exception in some jurisdictions.
A property whose current use and structure comply fully with the applicable zoning regulations. Conforming status is a positive underwriting signal — the use is legally established, dimensional standards apply as codified, and there are no known non-conformity issues. Lenders and title companies treat conforming status as a baseline for standard underwriting.
The number of dwelling units permitted per unit of land area, typically expressed as units per acre. Density limits control how intensively a parcel can be developed for residential uses. Commercial and industrial density is typically governed by FAR rather than unit counts.
The measurable requirements in a zoning code that govern how structures can be placed and sized on a parcel. Key dimensional standards include setbacks, height limits, floor area ratio (FAR), lot coverage, minimum lot size, and parking ratios. Zoning Assist retrieves dimensional standards directly from municipal GIS data and source-cites the applicable ordinance section.
The process of obtaining government approval to develop land in a specific way. Entitlement can include rezonings, variances, conditional use permits, site plan approvals, environmental review, and subdivision approvals. "Entitlement risk" refers to the probability that required approvals will be denied, delayed, or conditioned in ways that impair a project's feasibility.
A 0–100 score calculated by Zoning Assist that estimates how likely an entitlement application would be approved for a given parcel, based on the zoning district, applicable overlays, recent entitlement case outcomes in that jurisdiction, and applicable variance thresholds. Scores above 75 are considered favorable; below 40 is high risk.
The ratio of a building's total floor area to the area of the parcel on which it sits. FAR is a primary tool for controlling development intensity in urban and commercial zones. Roughly two-thirds of U.S. cities do not codify FAR in their zoning ordinance — instead using height limits, lot coverage, and density standards to control intensity. When FAR is not codified, Zoning Assist will display "Not Codified" rather than fabricate a number.
A zoning framework that regulates the physical form of buildings — massing, setbacks, facade requirements, and street interface — rather than strictly regulating land use. Form-based codes are common in urban cores and transit-oriented districts. Miami 21 is the largest form-based code in the U.S. In form-based code areas, traditional dimensional tables (FAR, lot coverage) may not apply; instead, standards are set by "transect zone" or "place type."
The maximum height a structure may reach on a parcel, typically measured in feet or stories from grade. Height limits vary widely — from 30–35 feet in suburban residential zones to unlimited (or very high) in urban commercial cores. Some jurisdictions measure height from average grade, others from finished floor elevation, and others from the base flood elevation in flood-prone areas.
The legally permissible, physically possible, financially feasible, and maximally productive use of a parcel of land. HBU analysis is a cornerstone of real estate appraisal and development underwriting. Zoning Assist's AI summary includes an HBU analysis section for each report, informed by the zoning district, dimensional standards, permitted uses, and market context.
A measure of the portion of a parcel covered by impervious surfaces — buildings, paving, and other hard surfaces that prevent water infiltration. ISR is used in place of lot coverage in many Florida cities (Orlando, Naples, St. Petersburg) and some Southeast and Midwest markets. The distinction matters for stormwater management and development intensity analysis.
A use or structure that was lawfully established under prior zoning regulations but no longer conforms to current zoning standards after a code amendment. Legal non-conforming uses may continue but are typically subject to restrictions: they cannot be expanded, and if damaged beyond 50% of assessed value, the structure may be required to conform to current code before reconstruction. This is a key lender concern — it limits the rebuilding rights that underpin collateral value.
The percentage of a parcel's total area that can be occupied by structures, typically measured as the building footprint divided by lot area. Lot coverage controls the built density and open space on a parcel. Some jurisdictions use ISR (impervious surface ratio) instead, which includes paved areas in the calculation.
A zoning classification that allows both residential and commercial uses on the same parcel or within the same building. Mixed-use zones are common in urban cores, transit corridors, and planned developments. They typically allow ground-floor retail or commercial with upper-floor residential. Development standards in mixed-use zones may differ significantly from single-use districts.
A structure that was lawfully built under prior dimensional standards but does not conform to current dimensional requirements — for example, a building that encroaches into a setback that was added after the structure was built. Non-conforming structures can typically remain but may face restrictions on expansion or reconstruction after damage.
A zoning designation imposed on top of the base zoning district that adds supplemental standards or restrictions for a specific area or land characteristic. Common overlay types include historic preservation overlays, floodplain overlays, airport approach overlays, hillside development overlays, transit-oriented development overlays, and environmental protection overlays. Overlay standards apply in addition to base zone standards, not instead of them.
A zoning designation used primarily in Arizona (Maricopa County and its municipalities) for large-scale developments governed by a project-specific development agreement rather than the standard zoning code. PAD zones have their own development standards — setbacks, heights, uses, and density — established through the original PAD approval. To understand what is permitted in a PAD zone, the specific PAD agreement must be obtained directly from the jurisdiction.
Similar to a PAD, a Planned Unit Development is a project-specific zoning designation used in many states outside Arizona. PUDs allow a developer to depart from standard zoning in exchange for a comprehensive site plan approved by the governing body. PUD standards are set by the PUD agreement and vary significantly by project.
A land use that is allowed by-right in a zoning district without any additional discretionary approvals. Permitted uses are listed in the applicable section of the zoning ordinance for each district. Uses that are not listed as permitted are presumed to be prohibited unless classified as conditional or accessory uses.
A provision in a zoning ordinance that governs whether and how a legal non-conforming structure may be rebuilt after damage. Most jurisdictions apply a "50% rule" — if a non-conforming structure is damaged beyond 50% of its pre-damage assessed or replacement value, it cannot be reconstructed as-is and must conform to current zoning. Lenders underwriting loans on non-conforming properties must account for this risk, as it directly affects collateral rebuilding rights.
A formal legislative action by a governing body that changes the zoning classification of a parcel or area. Rezonings are discretionary — they require public hearings and council votes and are not guaranteed. A development project that requires a rezoning to proceed carries higher entitlement risk than a by-right project.
The minimum required distance between a structure and a property line. Setbacks are typically specified for front, rear, and side yard boundaries. They create open space around structures and regulate the buildable envelope on a parcel. Setback violations are a common issue on non-conforming properties and are a standard check in lender due diligence.
The land subject to flooding by the 1% annual chance flood event (also called the "100-year flood"), as mapped by FEMA. Properties in SFHA zones (Zone A, AE, AO, AH, V, VE) are subject to mandatory flood insurance requirements for federally-backed loans. SFHA status is a significant underwriting factor — it increases insurance costs, construction constraints, and regulatory risk.
A zoning classification used in form-based codes — most notably Miami 21 — that designates land based on its position on a rural-to-urban transect (T1 through T6). Transect zones regulate building form, frontage types, and use mix rather than specifying permitted uses in a traditional table. T1 is natural/undeveloped land; T6 is urban core. Understanding transect zones requires reference to the applicable form-based code, not a standard dimensional table.
A rezoning that increases the density or intensity of development allowed on a parcel — for example, changing a single-family residential designation to multi-family or commercial. Upzoning typically increases land value. Many state housing laws now require municipalities to upzone areas near transit as a condition of receiving state housing funds.
A discretionary approval that allows a landowner to deviate from specific dimensional standards of the zoning code due to practical difficulty or unnecessary hardship. Variances are typically granted by a Board of Zoning Appeals or Board of Adjustment. Area variances address dimensional standards (setbacks, height, lot coverage); use variances allow a use that is otherwise prohibited. Variances are property-specific — they run with the land and are recorded in the public record.
A geographic area designated in a municipality's zoning map with uniform land use regulations. Zoning districts are classified by primary use type — residential (R), commercial (C), industrial (I), agricultural (A), mixed-use (MU) — and numbered or lettered to indicate intensity (R-1 is typically less dense than R-3). Each district has its own schedule of permitted uses and dimensional standards in the zoning ordinance.
An official letter issued by a municipality confirming the current zoning classification of a specific parcel, the permitted uses in that zone, and the applicable dimensional standards. Zoning verification letters are often required by lenders for construction and acquisition loans and are a prerequisite for some title insurance endorsements. They are issued directly by the planning or zoning department — Zoning Assist reports support and expedite the process but do not substitute for an official letter.
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