The Improvements Record file is a record of structure improvements made to a property, including initial construction, renovations, additions, and repairs. This file contains the parcel number, Use Code description, improvement type, year built, and other features and dates related to the property's improvements.

This data set is a compilation of tax code area boundaries in Snohomish County, Washington. Tax code areas are formed from a composite of special purpose district boundaries such as cities, fire districts, school districts, etc. Tax code areas represent areas with a uniform tax (levy) rate for that area. The boundaries of the present data set are compiled from data sets for many of the taxing districts that were compiled from legal descriptions for each annexation from the original incorporation onward. Legal descriptions were interpreted without assumption of intent or bias from any pre-existing maps. Spatial registration conforms to features in the Snohomish County parcel data set. For areas where special purpose district boundaries have not been converted, the boundaries were taken from a manually maintained atlas.