This data product is a combination of data from the five appraisal districts and is only updated once a year. These disparate datasets are combined together and an attempt was made to bring it into a single schema. NOTE: the City of Dallas does not warranty the accuracy of this data.
Tax appraisal data is maintained by County Appraisal Districts. The City of Dallas is part of five different counties. To obtain the source data used to create the parcel data set, it will be necessary to contact the county appraisal districts directly.

The City of Dallas Hub Site:
https://dallasgis.maps.arcgis.com/home/item.html?id=90a5d230a11d4c379684a93119eab189

This hubsite covers the City of Dallas Tax Appraisal Values for residential and commercial properties with data dating from 2015 to 2021

Disclaimer

The accuracy is not to be taken / used as data produced by a Registered Professional Land Surveyor for the State of Texas. For this level of detail, supervision and certification of the produced data by a Registered Land Surveyor for the State of Texas would be required. "This product is for informational purposes and may not have been prepared for or be suitable for legal, engineering, or surveying purposes. It does not represent an on-the-ground survey and represents only the approximate relative location of property boundaries."

(Texas Government Code § 2051.102)