Dataset · Structure & Materials
Multifamily Construction Permit Data
Multifamily permit data records the apartment and condominium construction authorized by US cities and counties: new buildings, additions, conversions, and major renovations. Builty structures these records nationally and, crucially, parses the number of dwelling units out of the permit text, so supply can be measured in units rather than filings.
Units
Counted, not just permits
2-4 & 5+
Structure classes split
Net
Demolitions subtracted
Address
Level of granularity
Why units
Unit counts, not permit counts
One permit can authorize a single duplex or a 300-unit tower; counting filings tells you almost nothing about supply. Builty reads the unit count out of the permit description and classifies the structure, so a market's pipeline can be measured the way it's actually underwritten.
Units per project
Parsed from the permit text where the jurisdiction publishes it, not estimated from an average.
Structure class
2-4 unit and 5+ unit buildings separated: different financing, different risk, different market.
Net of demolition
Units removed are counted too, so replacement projects don't read as pure new supply.
What's in the data
The fields that measure supply
| Field | Example | Why it matters |
|---|---|---|
new_units | 288 | The supply number, parsed from the record |
structure_class | 5+ unit | Separates duplex/triplex from mid- and high-rise |
demo_units | 12 | Enables a net-new-units view |
work_type | New construction | New build vs addition, alteration, or conversion |
date_submitted / issued / finaled | 2025-03-11 | Filing-to-completion timeline per project |
project_value | $41,200,000 | Declared job value where published |
street_address + geo | Locality · county · CBSA | Submarket-level rollups |
attributes | stories, construction type, parking | Parsed from the description text |
contacts | developer · contractor · owner | Who is building, where published |
Transformation
A multifamily permit, decoded
The unit count, the single most valuable number in the record, is usually buried in shorthand.
Raw record, as published
Builty structured output
"NEW 4 STORY 288 UNIT APT BLDG W/ PODIUM PKG, TYPE V-A OVER TYPE I-A, DEMO (12) UNIT EXIST"Sun Belt metro
Work: New construction · Property: Multifamily, 5+ units · New units: 288 · Demolished: 12 · Net: +276 · Stories: 4 · Construction type: V-A over I-A · Parking: Podium
Who uses it
From supply pipelines to habitational risk
Multifamily investors & REITs
Submarket supply pipelines and absorption timing, months before deliveries show up in comps.
Capital markets
A physical read on housing starts and completions, at address level rather than sampled monthly counts.
Lenders
Construction-loan monitoring and draw validation, plus early sight of competing supply near an asset.
Insurers
Habitational risk: building age, construction type, sprinklers, and renovation history across a portfolio.
Suppliers & manufacturers
Demand for materials and systems, visible at the moment a project is permitted.
Housing policy & research
Whether permitted units actually get built, and where, from primary local records.
Coverage
National, deepest where multifamily is being built
Collected directly from local permitting authorities, with the deepest history in the metros absorbing the most multifamily development.
New construction & renovation2-4 and 5+ unitConversions & adaptive reuseHistorical + ongoing
Also available as a single-state deep dive. See Virginia data in depth →
FAQ
Frequently asked questions
What is multifamily permit data?
Multifamily permit data is the public record of apartment and condominium construction authorized by a city or county: new buildings, additions, conversions, and major renovations. The most valuable element is the number of dwelling units each permit authorizes, which is what turns a list of filings into a measure of housing supply.
How do you count units from a building permit?
Jurisdictions rarely publish a clean unit field; the count usually sits inside the free-text description, written a different way in every city. Builty parses that text to extract the number of units, classifies the structure as 2-4 or 5+ units, and separately captures demolished units so net new supply can be measured.
How is this different from Census housing starts data?
The Census Bureau's Building Permits Survey reports monthly unit counts by place, collected from roughly 8,600 jurisdictions with the remainder statistically imputed. Builty provides the underlying records themselves (address-level, project-level, with dates and attributes), so you can drill into a submarket or a single site rather than reading an aggregate.
Can you track apartment conversions and adaptive reuse?
Yes. Office-to-residential and other conversions appear in the permit record as alterations or changes of occupancy with a resulting unit count, which is often the earliest hard evidence that a conversion is actually proceeding rather than merely announced.
Does the data show whether permitted units were actually built?
The record carries the permit's status and its issued and finaled dates, so a project can be followed from filing through completion, including the ones that stall and never finish.
How is the data delivered?
By API, bulk file, or an ongoing subscription feed scoped to the metros, structure classes, or unit thresholds you follow. Sample first, in your preferred format.
See the pipeline in your markets
Send us the metros or submarkets you follow, and we'll return a sample cut with unit counts.
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