Dataset · Structure & Materials

New Construction Permit Data

New construction permit data is the record of every new building authorized by a US city or county: single-family homes, townhomes, apartments, accessory dwelling units, and commercial structures. Builty structures these nationally with the dates that bracket the build, so a property's age comes from the permit that authorized it.

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Build year

From the authorizing permit

ADUs

Detached, attached, conversion

25+ yrs

Of construction history

Address

Level of granularity

Why permits

Building age, from the permit that authorized the building

Year built usually arrives from an assessor file. That figure is an estimate, it is revised inconsistently, and it never records the accessory dwelling unit that went up in the back yard in 2021. A permit is dated evidence that a specific structure was authorized at a specific address, and it is the same record whether the building went up last year or in 1996.

What's in the data

Structure-level fields, parsed straight from the permit.

Signal	What it carries
`build_year`	The authorizing permit's date, with submitted, issued and finaled on one timeline
`structure_type`	Single-family detached, townhome, duplex, multifamily, ADU, commercial
`new_units`	Dwelling units the permit creates
`demo_units`	Demolitions, so net change is computable
Size & stories	Square footage and story count where the jurisdiction publishes them
Build duration	Permit-to-final elapsed time, which is a market signal in its own right
Builder	The permitted builder or general contractor, where named

Transformation

A new-construction permit, decoded

Jurisdictions file a whole house as one line of shorthand.

Raw record, as published

Builty structured output

"NEW SFD CVRD PORCH PATIO ATT GAR 3BD 2BA 1875 SF"Greeley, CO · residential

Project: Structure.NewConstruction · Structure: Single-family detached · Size: 1,875 ft² · Includes: covered porch, patio, attached garage · Build year: from this permit's dates

Accessory dwelling units

ADUs are the hardest new construction to see. They rarely change a parcel record, they often do not move an assessor's year built, and in the states driving the volume they are the fastest-growing form of new housing. The permit is frequently the only dated evidence a second dwelling exists at all.

Signal	What it means
Detached ADU	A new standalone structure on an existing lot
Attached ADU	An addition that creates a second independent dwelling
Conversion ADU	Garage, basement or interior space converted to a dwelling
Junior ADU	A bedroom-scale unit within the existing footprint, permitted separately in some states
Arrival year	The dated permit, which is what makes ADU growth mappable over time

Who uses it

Building age for underwriting

A dated build year at the address, and the ADU that the parcel record does not show.

Housing supply

Units created and demolished, by jurisdiction and by month, with net change computed.

Homebuilder tracking

Who is building what and where, from the permitted builder name.

Land & site selection

Where entitlement is actually converting into construction, ahead of completion data.

Local government

Housing element and APR reporting derived from the same permits the filing is built on.

Market research

Decades of construction history in one schema, at address level.

FAQ

Frequently asked questions

How do I find the year a house was built?

An assessor record gives an estimated year built. A building permit gives the dated record of the authorization itself, which is why permit-derived build year is more defensible and catches structures added later, including ADUs, that a parcel record misses.

What is an ADU permit?

A permit authorizing an accessory dwelling unit: a second, independent dwelling on a lot that already has a home. It may be detached, attached, or a conversion of existing space such as a garage or basement. The permit is often the only dated record that the unit exists.

Does new construction data include multifamily?

Yes, and unit counts are carried through. Multifamily has its own page because unit counts, structure class and demolitions need more room than a single field.

How far back does construction history go?

25+ years nationally, deeper in individual jurisdictions. Each state page states the year that state reaches sustained volume.

Can I scope this to one market?

Yes. Any set of jurisdictions, structure types, or date ranges, by API, bulk file, or ongoing feed.

Keep reading

Structure & Materials

Multifamily →

Structure & Materials

Building Materials →

Overview

US Building Permit Data →

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