Bulk property owner data is the county assessor's parcel roll delivered as a file or a feed instead of a search box: one row per parcel with the site address, the taxpayer's mailing address, assessed values, and, in some counties, the owner's name. Most counties publish it free through one of three channels (a bulk extract, a GIS feature service, or an open data portal), and joining it to a list of addresses takes an afternoon. The part nobody tells you is that a growing number of counties strip the name out of the bulk file, on purpose, and leave the mailing address in.
We load three county rolls every night to enrich the code violation data behind FlaggedLeads, so this is a description of files I actually parse, not a directory. It sits under the public records guide for real estate, and it is the bulk version of looking up a property owner by address, for the moment when the list outgrows the search box.
The three ways a county hands out its roll
| Channel | What it is | What you get | Refresh | Where it bites |
|---|---|---|---|---|
| Bulk extract | Zipped CSV or pipe-delimited text, one file per table | The whole roll, every field the county chose to publish | Weekly to monthly | Files are large, layouts change without notice, names may be stripped |
| GIS feature service | An ArcGIS REST endpoint behind the county parcel map | Parcel polygons plus a subset of attributes, queryable by area or field | Daily to weekly | Attribute set is thinner than the extract; record caps per request |
| Open data portal | Socrata or ArcGIS Hub catalog | The same layers, with an API and a download button | Varies by dataset | Coverage is whatever the county chose to publish |
Three Puget Sound counties, three different answers to the same request:
- King County publishes its assessor extracts as zipped CSVs: Real Property Account, Parcel, Residential Building, Real Property Sales, and a Lookup table that decodes every coded field. The parcel geometry comes separately from the county GIS parcel service. We pull all four tables for five cities, about 270,000 parcels, and the account file carries a taxpayer mailing address for 98% of them.
- Pierce County runs it two ways: an open ArcGIS layer of 339,747 tax parcels with site address, mailing address, values, and use code but no name, and weekly pipe-delimited flat files on the county's downloads page that do carry the taxpayer name. The downloads page refuses non-browser clients, so scripts fail where a person succeeds. The Pierce County open data hub is the front door.
- Snohomish County is the most generous of the three. Its GIS open data page offers the assessment roll as CSV and Excel, updated three times per week, and the parcel feature service carries an OWNERNAME field. Every Snohomish parcel we hold has a name.
Outside Washington the pattern repeats. Scott County, Iowa posts dated folders of "the most commonly requested property assessment data and characteristics for ALL parcels," free, with a readme. Most counties of any size do something like it; the search terms that find it are "assessor data download," "extract," and "open data," on the assessor's or GIS department's site, not the property search page.
What the file actually looks like
The fields below are from the files we parse, as of August 2026. County layouts differ in naming and agree in shape.
| County, file | Parcel key | Site address | Owner name | Mailing address | Values |
|---|---|---|---|---|---|
King, Real Property Account (EXTR_RPAcct_NoName.csv) |
Major + Minor (10 digits) | In the Parcel table, not here | Removed around March 2026 | AttnLine, AddrLine, CityState, ZipCode | Appraised land and improvements |
| Pierce, Tax_Parcels layer | 10-digit PIN | Site_Address | Not in the layer | Delivery_Address, City_State, Zipcode | Land and improvement values |
| Snohomish, Parcels layer / assessment roll | Parcel ID | SITUSLINE1, SITUSZIP | OWNERNAME | TAXPRLINE1, city, state, ZIP | MKLND, MKIMP, MKTTL |
Two practical notes. The parcel key is the join, always; matching on address text fails on unit numbers, directionals, and every "NE" the county wrote as "N E". And the mailing address is the more valuable column even where the name exists: it is the absentee owner signal, and about 58% of the distressed-property leads we score, where posture can be determined, have a mailing address that does not match the property.
Why the name is missing
The King County file name says it: NoName. The taxpayer name was in the extract until early 2026 and then it was not, and the county's download page now opens with an acknowledgment that Washington law "prohibits the use of lists of individuals for commercial purposes." That is RCW 42.56.070(8): the Public Records Act gives no agency authority "to give, sell or provide access to lists of individuals requested for commercial purposes." A parcel roll with a name column is arguably a list of individuals. A parcel roll with a mailing address is a list of parcels. The county kept the second and dropped the first, and you can still read any single taxpayer's name on the county's per-parcel lookup, one at a time.
Idaho went further. Idaho Code § 74-120 says no agency "may distribute or sell for use as a mailing list or a telephone number list any list of persons" without their permission, and in Sentry Dynamics v. Ada County the Idaho Supreme Court held that a county-wide owner list is a "list of persons" and that the county may require a requester to assure the data will not be used for mailing before releasing it. A bulk owner file used for a mail campaign is exactly what that statute is aimed at.
None of this is legal advice, and Washington counties still hand out the mailing addresses. But if your plan is "download the roll and mail it," read your state's version of that clause first, because the counties are starting to.
How to join your list to the roll
- Get a parcel number for every address. Run the list through the county GIS reverse lookup or the assessor's search; the APN is the only key that survives. Fix the addresses that fail to resolve by hand, since those are usually the distressed ones.
- Download the extract, not just the map. The bulk account file has the mailing address and values; the GIS layer has the geometry and site address. You want both, keyed on the parcel.
- Normalize before you join. Zero-pad the minor number, strip unit designators consistently, uppercase everything. The address-only skip trace workflow covers the cleanup, and the same rules apply here.
- Join on the parcel key. Your list plus the account file gives you a mailing address per parcel. Your list plus the parcel file gives you the site address and use code. Left-join both onto your list and count the unmatched rows before doing anything else.
- Derive the absentee flag. Compare the mailing address to the site address. A mismatch or a PO Box is an owner who does not live there, which is the single filter that most changes what a mail campaign returns.
- Fill names last, and only for the list you will actually contact. Per-parcel lookup on the county site for a few dozen; a skip trace for hundreds, where the vendor returns a name and phone against the address and mailing address you already hold. In our benchmark of 691 traces, 69% of paid results returned the same mailing address the county had already published free, so do the join before you pay.
When to pay for it instead
| Source | Coverage | What it adds | What it costs |
|---|---|---|---|
| County direct | One county at a time | The authoritative record, freshest, free | Your time; a different layout per county |
| Regrid | Nationwide parcels, standardized schema | One layout for every county, owner and mailing fields where the county publishes them | Per-county or subscription pricing |
| Data platforms (PropStream and peers) | Nationwide, licensed from aggregators | Names, phones, and filters on top of the roll | Monthly subscription; see where the data comes from |
One county, go direct. Five counties in three states, pay for the standardized schema and spend the saved week on the list instead of the parsers. What you are buying from a vendor is never the data, which the county already published. It is the layout.
Frequently asked questions
Can I download the county tax roll with owner names?
In some counties. Snohomish County, Washington publishes its assessment roll with owner names three times a week. King County removed the taxpayer name from its bulk extract in early 2026 and kept the mailing address. Idaho counties may withhold the list entirely unless you agree not to use it for mailing. Check the field list in the county's readme before assuming.
Is bulk property owner data free?
From the county, almost always. Extracts, GIS layers, and open data portals are public records published at no charge, and a few counties charge a media fee for very large files. The paid versions add a standardized layout, phone numbers, or nationwide coverage, not different underlying data.
How often does county parcel data update?
It depends on the channel. Snohomish County refreshes its roll three times a week, Pierce County's flat files are weekly, and King County's extracts follow the assessor's schedule. Sales and ownership changes lag recording by days to weeks in every county, which is why a vendor's copy of a county's copy is always older than the county.
Can I use county owner data for a mailing list?
That is a legal question, and it varies by state. Washington's Public Records Act says agencies may not provide lists of individuals for commercial purposes, and King County makes you acknowledge it before downloading. Idaho's statute bars distributing any list of persons for mailing without consent, and its Supreme Court upheld a county conditioning release on a no-mailing assurance. Read your state's clause before you build the campaign.
The roll tells you who to write to. It does not tell you who needs a letter. Our free map shows the properties with an open code case across seven Puget Sound markets, mailing-address enriched from these same rolls, and it takes no account to look.