Methodology
This is a Your-Money-or-Your-Life topic, so our standard is simple: every rule is cited to an official source and dated, and every dollar figure is a clearly-labeled estimate. Here is exactly how the site is built.
How exemption rules are verified
There is no single national dataset of property tax exemption rules — they live in 51 separate statutory and tax-agency sources, and they change most legislative sessions. Every rule on this site is read from an official source during research: the state statute text, the state Department of Revenue / Comptroller / Tax Commission, or the state's official exemption application form. Third-party summaries (law-firm posts, mortgage blogs, aggregators) are never used as a citation — at most they help us locate the official source.
Each program record carries its statute_citation, one or more official source_urls, and a verified_date. Dollar amounts are cross-checked against a second official artifact (typically the application form PDF) before they are marked verified. A state ships only when its records pass this citation gate; partially-verified states ship only their verified programs. An honest, smaller site beats a complete, wrong one. 47 states are verified so far.
How savings estimates are derived (the ACS effective rate)
We do not look up your actual millage. Instead we estimate a typical effective tax ratefor each county from the U.S. Census Bureau's American Community Survey (ACS) 5-year estimates:
effective_rate = median real estate taxes paid ÷ median home value
Worked example.If a county's ACS median real estate taxes paid is $4,500 and its median home value is $300,000, the effective rate is 4,500 ÷ 300,000 = 1.50%. A $10,000 assessed-value homestead exemption in that county is then estimated to save about 10,000 × 1.50% = $150 per year. This is an estimate of a typical bill in that county, not your specific bill.
Top-coding and floor estimates
ACS medians are top-coded: above a fixed ceiling, the reported median is capped, so in the most expensive counties the true taxes or values exceed what the federal data can measure. We flag those counties as rate_capped. On their pages, computable savings are shown as a floor estimate(“at least ~$X”) rather than a point estimate — the real figure is at least that much. This is applied consistently and is why some counties show a “≥” figure.
The mechanism model — what does and doesn't get a dollar figure
Exemptions work in different ways, and only some are honestly reducible to an annual dollar figure. We model the mechanism explicitly and only compute what is computable:
| Mechanism | Dollar estimate? | How we present it |
|---|---|---|
| Value reduction | Yes | amount × effective rate (adjusted for assessment ratio) |
| Percent reduction | Yes | percent × home value × effective rate |
| Flat credit | Yes | the credit amount itself |
| Full exemption | Yes | 100% of covered value × effective rate |
| Assessment freeze | No | qualitative — savings grow over time, no single figure |
| Tax ceiling | No | qualitative — caps the bill at the year you qualify |
| Deferral | No | qualitative — postpones, does not forgive, the tax |
Freeze, ceiling, and deferral programs never get an invented dollar figure — we explain what they do instead.
Scope of tax and assessment ratios
Some exemptions apply only to certain taxing units (for example, a homestead amount that applies only to school district taxes). Where a verified official ratio exists, the estimate is computed against that share; otherwise it is presented as an upper bound with the scope caveat stated inline. Separately, in states where exemptions reduce assessedvalue and assessed value differs from market value (for example Illinois' EAV, Georgia's 40% ratio), the calculation uses the verified assessment ratio from the official source; where no reliable ratio is available, the state renders eligibility information without a dollar estimate.
What v1 deliberately excludes
v1 covers statewide programs only. Many states let counties and cities adopt optional or enhanced exemptions with locally-set limits; those local-option programs are out of scope for now, and every page carries a standing note to confirm them with your county assessor. We would rather omit a program than approximate it.
Update cadence
Rules are re-checked against their official sources on a rolling basis and after major legislative changes; each program shows its own verified date, and each county page shows the ACS vintage its rate came from. If you spot something out of date, tell us.
Source types we cite
- State statutes and constitutional provisions (official legislature sites).
- State Department of Revenue / Comptroller / Tax Commission exemption pages.
- Official state exemption application forms (used for amount cross-checks).
- U.S. Census Bureau ACS 5-year estimates (for county effective rates).
This methodology is maintained by By Sharon Ben-Moshe. Corrections are welcome and are dated when applied.