Methodology

CountyTaxTools is a county-level tax data platform. This page documents the full methodology behind the data published on every county, state, calculator, and comparison page on this site - source hierarchy, verification workflow, what each data state means, calculator inclusion rules, the email confirmation process, update cadence, and how corrections are handled.

How CountyTaxTools Verifies County Tax Information

Every published tax fact on this site passes through the same verification workflow before it appears on a county page, a calculator, or a comparison table.

The workflow has five steps:

  • 1. Identify the official source. Each tax fact is mapped to a specific official government source - county commissioner of revenue, city treasurer, state revenue department, state transportation department rate survey, or an official state code section. Third-party aggregators and news articles are not accepted as primary sources.
  • 2. Extract the value. We directly access the source - by fetching the page, navigating via browser, extracting from an official PDF, or receiving an official email reply - and pull the exact published value. Session memory, AI model output used alone, and inferences from neighboring counties are not accepted as extraction methods.
  • 3. Record the evidence. The source URL or document, the access method, the access date, and the verbatim extracted quote are written to structured data tables in our internal data layer. Every published fact points back to a source ID and a verification log entry.
  • 4. Classify the status. Each fact is marked verified, partial, pending, or unresolved. Only verified facts are published as settled numbers. Other states are either disclosed or omitted, never presented as confirmed.
  • 5. Publish or queue. Verified facts publish to the county page, calculator, and comparison page. Unresolved items go to our manual verification queue for outreach. A page publishes when at least the core verified facts are in place; unresolved items are disclosed on the page itself, not hidden.

This is the same workflow whether the jurisdiction is Fairfax County or a small independent city. The step count does not collapse for higher-traffic counties.

Source Hierarchy

When multiple official sources exist for the same tax fact, we use the following order of preference. Higher sources outrank lower sources if they disagree.

  1. Official county, city, or state government web pages. The commissioner of the revenue, treasurer, assessor, city finance department, or state revenue/taxation department pages for the jurisdiction. These are the primary source for current adopted rates, PPTRA percentages, and due dates.
  2. Official government PDFs. Adopted budget documents, published rate ordinances, formal rate surveys such as the Virginia Department of Transportation Local Tax Rates Survey, and official board of supervisors resolutions. Extracted with pdfplumber and cited by page number.
  3. Official email confirmations from named government officials. Direct replies from the commissioner of the revenue, treasurer, FOIA officer, or equivalent named contact confirming a specific value. Stored in the verification reply log with the sender name, email address, date, and verbatim quote.
  4. State tax department aggregated data. Where a state revenue or taxation department publishes consolidated data for its jurisdictions - Virginia Department of Taxation sales tax rate tables, for example - this is used for state-scoped facts that the state agency is the authoritative source for.
  5. Official state code sections. Statute references that establish formulas, relief structures, or procedural rules. Used to document the legal framework, not to infer a specific current numeric rate.

Items that cannot be resolved under this hierarchy are moved to the manual verification queue. That queue drives the outreach process described below - it is not a placeholder for guesses.

We prefer official government domains (.gov, .us). Where a jurisdiction's confirmed primary site operates under a different domain, we use that domain when it is the authoritative official source. We do not treat aggregator sites as official sources even where they are convenient or heavily trafficked.

What Verified, Partial, Pending, and Unresolved Mean

Every tax fact on this site carries one of four status labels internally. Each label has a specific meaning, and each controls what appears on the public page.

  • Verified. The official source has been accessed, the value has been extracted, and the extraction is recorded in our verification log with a verbatim quote and a dated access record. Verified values are published as settled facts on the county page, the calculator, and the comparison page.
  • Partial. Some fields for the jurisdiction are verified; others remain unresolved. The page publishes with the verified fields clearly shown and the unverified fields either omitted or explicitly disclosed as pending confirmation. A partially verified page is labeled as such in the Site Master Tracker.
  • Pending. An outreach request has been sent to the official source (typically an email to the commissioner of the revenue or treasurer) and we are awaiting a reply. The value does not appear as a confirmed number on the public page. Where a prior-year value exists from an earlier verified extraction, we may display that prior-year figure with explicit year attribution and a disclosure that the current year is pending confirmation.
  • Unresolved. No official source has produced the value, no outreach reply has returned a value, and no prior-year verified value is available. Unresolved items are never published as confirmed facts. They are either omitted from the public page or surfaced as a disclosure directing the reader to the official jurisdiction contact.

The status of every county fact is tracked in the verification log. When a pending item is resolved, its status changes to verified and the page is updated in the same session that the resolution is recorded.

Partial Verified Build Rule

Tax data for any single jurisdiction is not a monolith. A county page may have a fully verified real estate tax rate but a pending PPTRA percentage. It may have a verified vehicle rate but an unresolved due date. Holding every page until every single field is resolved would slow the site to a crawl and would not serve readers any better than a page with clearly disclosed uncertainty.

The Partial Verified Build rule governs how we handle this:

  • A county page may be built and published when its core verified facts are in place and all unresolved items are either omitted or clearly disclosed as pending confirmation on the page.
  • A failed extraction on one field - for example, a PPTRA percentage that the county has not yet published - does not block the entire page. The page publishes with that field disclosed, and the unresolved item moves to the manual verification queue for outreach.
  • A failed extraction on one field does not freeze the overall build program. The next county in the authorized build sequence may proceed while one prior county has a field pending confirmation.
  • Unresolved items are tracked until resolved. When the official source confirms the value, the page is updated, the calculator is updated, the comparison page is updated, the verification log is updated, and the manual verification queue entry is narrowed or closed.

A partial verified page is never presented to the reader as fully confirmed. The uncertainty appears on the page itself - in the section that covers the affected data, and in the sources section at the bottom. Pages labeled Partial Verified Build in the Site Master Tracker carry that attribution for anyone reviewing the site's build history.

Calculator Inclusion Rules

A calculator on this site only covers a jurisdiction where the specific rates that calculator depends on are verified. An unresolved rate is not substituted with an estimate or a neighboring-county figure.

Each Virginia calculator has its own inclusion rule:

  • Car tax calculator (/calculators/virginia-car-tax/). A jurisdiction is eligible only when the vehicle personal property tax rate is verified AND the PPTRA relief percentage is verified. Both values must be traceable to a named official source - a county calculation page, an adopted budget, or a direct email confirmation from the commissioner of the revenue. If PPTRA is pending or unresolved, the jurisdiction is not added to the calculator dropdown even if the rate is confirmed. This prevents silent substitution of a neighboring county's relief percentage.
  • Property tax calculator (/calculators/virginia-property-tax/). A jurisdiction is eligible when the real estate tax rate per $100 of assessed value is verified for the covered tax year. The calculator displays the source year with every rate. Where a jurisdiction has overlapping town or district rates that materially change the effective rate, those overlapping rates are documented on the county page rather than silently bundled into the calculator output.
  • Sales tax calculator (/calculators/virginia-sales-tax/). A jurisdiction is eligible when its combined sales tax rate - state base, local component, and any regional district surcharge - is confirmed against the state taxation department tables and, where applicable, the regional district statute that establishes the surcharge. The 1.0% statewide qualifying food rate is handled in the calculator UI as a separate item type so readers do not accidentally apply the general merchandise rate to food purchases.

A jurisdiction that is live as a county page with partial verified status may still be excluded from one or more calculators if the specific fields that calculator depends on remain pending. Page coverage and calculator coverage are tracked separately for this reason.

Email Confirmation Workflow

Email replies from named government officials are a recurring verification source, particularly for PPTRA percentages, personal-use vehicle rates, and due dates that are not always published on county websites. Each confirmed reply is processed through a specific workflow rather than only updating the affected page.

When an official email confirmation arrives:

  • Reply log. The full reply is archived in project-docs/verification/county-outreach-reply-log.md with the sender name, official title, email address, date, and verbatim quote of the confirmed value. This is the primary evidence record.
  • Outreach tracker. The corresponding row in project-docs/verification/county-outreach-tracker.csv is updated with resolution date, extracted values, and status change. The active outreach queue is narrowed or cleared for that jurisdiction.
  • Manual verification queue. The relevant entries in project-docs/planning/MANUAL_VERIFICATION_QUEUE.md are narrowed or closed. If the reply resolves only part of a multi-field MVQ item, the item is narrowed to the remaining unresolved fields rather than closed entirely.
  • Data layer - source row. A new row is added to data/master/07_tax_sources.csv with a dedicated source ID (for example, SRC-VA-700-VT-EMAIL-2026), a gov_correspondence type classification, a high confidence rating, and a manual_verification access method.
  • Data layer - claim row. A new row is added to data/master/08_tax_source_claims.csv for each confirmed value, with verification_method set to manual_human_review, verification_status set to verified, and the verbatim quote stored in the extracted_quote field.
  • Data layer - verification log. A new entry is added to data/master/13_verification_log.csv recording the verification event.
  • Public pages. The affected county page is updated in full - intro, key takeaways, at-a-glance row, the specific tax section, the sources section, the FAQ, meta tags, and the WebPage schema dateModified. The old caveated language is removed where the confirmation resolves the caveat.
  • Calculators. The calculator JavaScript data file and the calculator page HTML are updated. If the confirmation makes a jurisdiction newly eligible for a calculator, the dropdown, rates table, schema description, and intro prose are expanded.
  • Comparison pages. Any comparison page that covers the affected tax category is updated - comparison table rows, section prose, and "what is being compared" notes.
  • Global routing. The homepage search index, the Virginia hub featured and browse lists, the site map, and sitemap.xml lastmod are updated where the change affects them.

A confirmation that resolves only part of a question narrows the corresponding tracker entry. It does not silently close the entire entry. This prevents later sessions from mistaking a partially resolved issue for a fully confirmed one.

Update Cadence and Reverification

Tax rates are not static. Counties adopt new budgets each fiscal year. States adjust PPTRA relief percentages annually. Regional district surcharges get added or removed. The site is updated on the following cadence:

  • Annual. Every jurisdiction is reverified against its primary official source each tax year. The reverification touches the real estate rate, the vehicle personal property rate, the PPTRA percentage where applicable, and the sales tax tier. Verified facts carry an explicit source year so the reader can tell at a glance whether the figure on the page is the current-year adopted rate or a prior-year rate awaiting the new-year update.
  • On-confirmation. When a new official email confirmation or a newly published county rate document is received, the affected page, calculator, comparison, tracker, data layer, and verification log are updated in the same session that the confirmation is logged.
  • On budget adoption. When a county adopts a new fiscal year budget mid-year, the adopted rates are verified from the official budget document and applied. The prior-year rate is retained internally as a superseded source row so prior verification history is preserved.
  • On state statute change. If a state adjusts a sales tax tier, changes the PPTRA relief structure, or amends a formula reference we cite, the relevant calculator logic and all affected jurisdiction pages are updated together.

Where a jurisdiction has not yet published its current-year rate at the time a page is reverified, the page continues to display the most recent verified prior-year value with explicit year attribution ("2025 tax year") and a disclosure that the current year remains pending confirmation. The item moves to the manual verification queue for outreach. The page is updated again as soon as the current-year value is confirmed.

Correction Process

If you see a rate, date, formula, or other fact on this site that differs from the current official source, the correction process is the same whether you are a county official, a practitioner, or a reader who noticed a mismatch.

To submit a correction, email Contact@CountyTaxTools.com. Please include:

  • The county or jurisdiction affected and the specific URL where the value appears
  • The specific rate or fact that appears incorrect
  • The official source citation - URL and access date, or document name with section or page reference
  • The correct value as stated in the official source

When we receive a correction request:

  • We verify the correction against the official source cited.
  • If the source confirms the corrected value, we update the affected page, the calculator (if applicable), the comparison page (if applicable), the data layer source and claim rows, the verification log, and the change log.
  • If the source does not confirm the corrected value, or if additional clarification is needed, we open an outreach item and follow up with the named official contact for the jurisdiction.
  • We do not accept unattributed corrections. A correction without an official source citation is treated as a prompt for our own reverification of the figure, not as a direct replacement of the published value.

County and city officials identifying an error in our data are welcome to use the same contact. Where the correction originates from a named official, we attribute the updated source accordingly in the data layer and on the page.

Related Pages

Methodology documents the process. The following pages apply that process on the public side of the site: