Counties we cover

Single-family homes (assessor classes 2-02 to 2-10, 2-34, 2-78, 2-95).

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

Data and filing steps are ready; we are still checking the details before switching it on.

The Assessor's sales and parcel files are free to download, but using them to sell something counts as a commercial purpose that needs the Assessor's commercial-use request, and its API needs a key from the Assessor. Waiting on that agreement.

The Assessor publishes its sales and building data as weekly bulk files, not a query service we can call. It needs a data import first.

The county's public parcel service has owner, land use and acreage but no assessed values, building size or sales, so there is nothing to compare yet. The Board of Assessors' digest files would need an import.

We found no free query service for the Assessor's sales and building sizes; the data are downloads and need an import first. Denver's protest window is in May and early June.

The Property Appraiser and the state Department of Revenue publish the rolls and sales as weekly bulk files (CSV), not a query service. It needs a data import first, and then each county's petition deadline.

The county's parcel service has values, sizes and sales, but North Carolina counties keep the last reappraisal's values between general reappraisals (G.S. 105-287), so a market-value appeal is not open until the next one. We will add it when that opens.

Mecklenburg's appeals for a revaluation year open only after the new Notices of Value are mailed, and its page lists the 2023 revaluation as the latest. We will add it when the new values are published.

Same state data as the other Maryland counties, but most of the city's homes are rowhouses recorded in other classes and the detached homes sell too rarely to compare. It needs rowhouse support first.

They use the same state data and appeal process as the Maryland counties we cover. Each gets switched on once we have tested it against its own recorded data.

The county's open parcel service has market values and sale prices but no living area, and a fair comparison needs price per square foot.

Not researched yet. California values follow Proposition 13 purchase prices, so the comparison needs its own method before we can offer it.

Not researched yet: no data source has been checked.

Not researched yet: no data source has been checked.

Not researched yet: no data source has been checked.

Texas requires a state registration (a property tax consultant licence) to be paid for advising on a property tax protest, and Texas counties do not publish sale prices, which the sales comparison needs. A self-help packet sold for money does not fit.