Detached Accessory Dwelling Units (DADUs)

Permit records from the City of Seattle permitting system for building permits that create or demolish detached accessory dwelling units (DADU). Records begin in 1990 and are through the current year quarter.The permits in this layer are those that have either been completed or are currently issued. This data does not contain records for those permits that were issued but were not completed so are therefore not comparable to statistics that report permit issuance.Each record represents the number of units added or demolished for each housing type in the project. Therefore a single building permit may appear multiple times if there are a mix of unit types in the project.Housing unit types reflect the unit types regulated by the building codes and change through time. There has been no attempt to standardize these types and therefore reflect the unit types that existed at the time the permit was issued.  Unit types will be visible only for the time period they were in the code. For example, small efficiency dwelling units were not created in the code until 2016 and so will not appear as a type until that year.There may be multiple permits at any given address.

Data and Resources

Field Value
accessLevel public
catalog_@context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
catalog_@id https://data.seattle.gov/data.json
catalog_conformsTo https://project-open-data.cio.gov/v1.1/schema
catalog_describedBy https://project-open-data.cio.gov/v1.1/schema/catalog.json
identifier https://data-seattlecitygis.opendata.arcgis.com/datasets/SeattleCityGIS::detached-accessory-dwelling-units-dadus
issued 2020-01-05
landingPage https://data-seattlecitygis.opendata.arcgis.com/datasets/SeattleCityGIS::detached-accessory-dwelling-units-dadus
license http://opendatacommons.org/licenses/pddl/summary
metadata_type geospatial
modified 2021-11-23
old-spatial -122.4173,47.4938,-122.2427,47.7355
publisher City of Seattle GIS Program
resource-type Dataset
source_datajson_identifier true
source_hash 5c15a38172c68e3531130db6011aebe0bdcdd1fa
source_schema_version 1.1
spatial {"type": "Polygon", "coordinates": [[[-122.4173, 47.4938], [-122.4173, 47.7355], [-122.2427, 47.7355], [-122.2427, 47.4938], [-122.4173, 47.4938]]]}
theme {geospatial}
Groups
  • AmeriGEOSS
  • National Provider
  • North America
Tags
  • adu
  • aduapp
  • amerigeo
  • amerigeoss
  • ckan
  • geo
  • geoss
  • housing-units
  • national
  • north-america
  • permits
  • planning
  • united-states
isopen False
license_id other-license-specified
license_title other-license-specified
maintainer Planning_SeattleCityGIS
maintainer_email mapgis.mapgis@seattle.gov
metadata_created 2025-11-21T13:18:36.775532
metadata_modified 2025-11-21T13:18:36.775536
notes <p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'>Permit records from the City of Seattle permitting system for building permits that create or demolish detached accessory dwelling units (DADU). Records begin in 1990 and are through the current year quarter.</p><p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'></p><p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'>The permits in this layer are those that have either been completed or are currently issued. This data does not contain records for those permits that were issued but were not completed so are therefore not comparable to statistics that report permit issuance.</p><p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'></p><p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'>Each record represents the number of units added or demolished for each housing type in the project. Therefore a single building permit may appear multiple times if there are a mix of unit types in the project.</p><p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'></p><p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'>Housing unit types reflect the unit types regulated by the building codes and change through time. There has been no attempt to standardize these types and therefore reflect the unit types that existed at the time the permit was issued.  Unit types will be visible only for the time period they were in the code. For example, small efficiency dwelling units were not created in the code until 2016 and so will not appear as a type until that year.</p><p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'></p><p style='font-family:&quot;Avenir LT W01 35 Light&quot;, &quot;Avenir Next&quot;, Avenir, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size:16px;'>There may be multiple permits at any given address.</p>
num_resources 6
num_tags 13
title Detached Accessory Dwelling Units (DADUs)