Finding and Documenting Comparable Sales for Property Tax Appeals

Last reviewed: May 2026 · Coverage: Texas, California, Illinois, New Jersey, New York, Florida, Massachusetts, Connecticut, Pennsylvania, Ohio, Georgia, North Carolina

Comparable sales (comps) are the single most important evidence type in residential property tax appeals across all 5 launch states. This guide covers what makes a comp credible, where to find them, how to document them, and the state-specific recency and similarity rules that determine whether they'll be accepted.

What makes a strong comp

Across all states, decision bodies (BoR, ARB, AAB, CBT, BAR/SCAR) look for the same elements:

  1. Recent — sold within 12 months of the assessment date (with state-specific tightening)
  2. Similar — same neighborhood, similar size, age, style, condition, lot
  3. Documented — sale price, sale date, MLS data, photograph
  4. Arms-length — not a foreclosure, family transfer, or other distressed sale

Most appeal failures come from comps that fail one of these tests. The comps don't have to be perfect — they have to be defensible against the assessor's counter-comps.

Recency requirements by state

State Lien date / assessment date Comp recency expectation
Texas January 1 ~12 months pre/post (some flexibility for slow markets)
California January 1 3-6 months ideal (tighter than other states); 12 months acceptable; >12 months heavily discounted
Illinois January 1 12 months (BoR Rule 9 standard); PTAB applies more rigidly than BoR
New Jersey October 1 of pretax year 12 months pre/post; later sales discounted
New York Variable by locality (typically March 1) 12 months pre/post
Florida January 1 (FL Stat. §192.042) 12 months pre Jan 1; arms-length sales heavily preferred. Save Our Homes-capped homesteads need just-value comps even though the bill follows assessed value.
Massachusetts January 1 (Mass. Gen. Laws Ch. 59 §38) 12 months pre/post Jan 1; ATB applies a tighter standard than the abatement application stage.
Connecticut October 1 of revaluation year (Conn. Gen. Stat. §12-62a) 12 months on either side of the Oct 1 reval date. Non-revaluation years adjust the existing reval-year valuation; current sales are not directly probative.
Pennsylvania County-set base year (varies by county — Allegheny 2012, Philadelphia annual, others vary) 12 months around the county's base year (which may be a decade-plus old). Counties on stale base years route most appeals through Common Level Ratio (CLR) substitution rather than fresh comp analysis.
Ohio January 1 of sexennial reval / triennial update year (ORC 5713.03) 12 months pre Jan 1; arms-length sales heavily weighted. HB 126 (2022) sharply restricted school-district comp-driven counter-complaints.
Georgia January 1 (O.C.G.A. §48-5-3) 12 months pre Jan 1 strongest; arms-length recent purchase usually treated as best evidence at BOE. HB 92 (2024) eliminated automatic appeal-pending freeze.
North Carolina January 1 of county's reappraisal year (G.S. 105-283; 4-8 yr cycle per G.S. 105-286) Comps within 6-12 months before the reappraisal date — NOT current sales. Wake's 2024 reval values anchored at Jan 1 2024; appeals filed in 2026 still use 2023-Q4/early-2024 comps. Post-reval-date market data routinely rejected at PTC.

CA's 3-6 month tightness is unusual — Title 18 CCR rules and BOE Assessment Appeals Manual emphasize "as of the lien date" valuations more strictly than other states.

Similarity requirements

What "comparable" means varies modestly across states but the universal factors are:

In same-municipality matching:

How many comps to submit

The standard rule across most states is 3-5 comps. Submitting fewer than 3 risks dismissal under procedural rules (especially IL BoR Rule 9, "Three (but not more than five) comparable properties"). Submitting more than 5 typically produces no benefit and can dilute the strongest comps.

Practical rule: pull 8-10 candidate comps initially, then narrow to the strongest 5 that survive scrutiny on similarity and recency.

Where to find comps

Best sources, in rough order of credibility:

  1. MLS listing sheets (the standard residential comp source) — accessed via a real estate professional or MLS-data services. Most credible because it includes condition, days-on-market, and listing detail
  2. County recorder / register of deeds — sale prices via deed transfer documents (verifies arms-length transactions and sale prices)
  3. Tax assessor parcel records — your local CAD/assessor publishes parcel-level property characteristics + recent sales activity
  4. Zillow/Redfin (with caution) — useful for initial screening; data quality varies; not always accepted as primary evidence; verify against MLS or assessor records before submission
  5. USPAP-compliant appraisal — if you commission an appraisal ($400-$800 typical for residential), the appraiser's selected comps come pre-vetted

Documenting each comp

For each comp, prepare:

Most states' formal complaint forms (TX Form 50-132, IL DuPage BoR appeal form, CA Form BOE-305-AH, NJ Form A-1, NY Form RP-524) include space for this. Bring documentation in duplicate or triplicate for the decision body and the assessor.

Adjustments

Appellants are expected to make adjustments to comps for material differences. Standard adjustments:

Common comp-pulling failures

State cornerstones with specific rules

Practical takeaways

The Property Tax Desk Editorial Team