Washington State Parcel Database
NRSIG Budget: $1,056,606
Project Budget: $1,056,606
Timeline: Ongoing since January 2005
Partners: WA PWG


Parcel Data is Critical. Digital parcel data, stored in a geographic information system (GIS), is a critical source of information for resource land managers, community development needs, infrastructure maintenance, research, homeland security, business development, public safety, and more.

Redundant efforts are costly. When this project began, there was not a single source of GIS-based parcel information for Washington State. Efforts to collect, store, and manage county, state and federal parcel data were often redundant at all levels of government. Each public or private entity had to request data directly from over forty different data producers. Data from these entities was provided in many different formats and with differing attribute schemas. Many counties had license agreements that prohibited, or severely restricted, the ability of one data user to share parcel data with other users, making cross-agency or interdisciplinary research difficult, expensive, and unpredictable because no two groups were using the same data.

This project is designed to construct a single, regularly updated, statewide parcel dataset based on data provided by city, county, state, and federal agencies that develop and maintain parcel data within Washington State. The purpose is to reduce the cost, inefficiencies, and redundant efforts of state and federal agencies, as each independently and periodically contacts parcel data originators for current data sets. This project also seeks to support, where needed, local efforts involved in developing and maintaining parcel data. Key to success is identifying and addressing data distribution concerns.

Our Work

NRSIG, in collaboration with the Washington Department of Health established the Parcels Working Group (PWG) in October 2006. The PWG is a group of federal, state, tribal and local government participants working together to pursue the development and coordination of a statewide parcel framework data set that is accessible to various participating agencies. This group works together to identify the core attributes of the database, address the concerns of county parcel data producers, coordinate licensing agreements, and build working relationships with the county parcel custodians and key agency framework coordinators. The PWG is co-chaired by representatives from the Department of Health and the University of Washington.

NRSIG collects parcel data from each county Assessor’s office and/or GIS department and from federal and state agencies that produce parcel data in Washington State. As part of the data collection effort, we work to clearly communicate the project objectives with each data producer, and to address any questions or concerns. The goal is to collect data annually at a minimum.

Data from the various producers are not standardized, and change over time. We develop and update methodologies for each producer to transform their data into a normalized (standardized) data set for the entire state with a consistent file type, attribute structure, and spatial reference. Where there is interest, we have developed these transformation methodologies in collaboration with parcel data producers. All original metadata is maintained, and data about the normalizing procedures is integrated for complete documentation of the statewide data set. In almost all cases, the normalized data will be a simplified version and/or a subset of the original data. The original non-normalized historical data is retained and is available for reference. Parcel data producers have the opportunity to review and comment on the normalized data and transformation methodology.

NRSIG developed and maintains a data sharing portal for distribution of the Washington State Parcel Database. This portal provides members of the Parcels Working Group a single point of contact and timely access to statewide GIS parcel data.


Four versions of the database have been developed between 2007 and 2012. Work is ongoing to continue development of future versions of the database.

To date, 65 agencies / organizations have downloaded the Washington State Parcel database and are using it for 252 documented projects.


Washington State Parcel Database Website

How the Washington State Parcel Database has been used