Plat Street has run appeal-deadline pieces jurisdiction by jurisdiction: Michigan's May 31, Cook County's rolling summer windows, Connecticut's revaluation cycle, New Jersey's April and May dates. This is the consolidated calendar for commercial owners inside districts, built around the jurisdictions where a revaluation, a statutory change, or district capture makes this cycle's appeal decision non-routine.

Read this first, because it applies everywhere below. A successful assessment appeal on a property inside a TIF or district capture area reduces the increment as well as the owner's bill. Plat Street states that plainly rather than avoiding it: the interests of an appealing property owner and the district managing that owner's corridor are, on this one question, opposed. Owners should appeal on the merits regardless. District managers should model an appeal-driven base erosion into multi-year capture projections rather than being surprised by it, and the jurisdictions below are where that erosion is most likely this cycle.

| Jurisdiction | Window | What makes this cycle different |

|---|---|---|

| Lackawanna County, PA | Formal appeal hearings began Aug. 4, running through October; new assessments certified Nov. 14, effective for 2026 tax bills and after | First countywide reassessment in nearly six decades, begun in 2022. Thousands questioned tentative values during the informal review that closed earlier this year. Rates fall as values rise to keep the process revenue-neutral for taxing bodies, but rates are not set until after Nov. 14 certification, meaning owners appeal a value without knowing the rate |

| Allegheny County, PA | Appeal deadline moved to Oct. 1 | A moved deadline is the most common cause of a missed appeal. Confirm the current-year date directly with the county rather than from prior-year practice |

| Cook County, IL | Rolling by township through the fall; township-specific deadlines posted when each township opens | South and west suburbs are under reassessment in 2026. Properties in the north suburbs and the City of Chicago are reassessed only on division work, permits, or special circumstances, but owners in non-reassessment townships can still appeal when their township opens |

| Alabama | Appeals accepted roughly April through August; 30 days from the date of the valuation notice | HB73 (Act 2024-344) caps annual increases in taxable assessed value for Class II commercial property at 7 percent. If a property is not under reassessment, the prior-year value carries forward and must be contested by the same deadline. County Boards of Equalization do not accept late filings, and the value becomes final |

| Colorado | Board of Equalization deadlines typically May 31; 2026 is the second year of the odd-year reassessment cycle | Colorado permits an abatement appeal covering the two prior tax years, provided no appeal was filed in those years. Owners who skipped a cycle have a recovery path most other states do not offer |

| Maryland | SDAT issues new notices to one-third of properties at the end of December; 45 days from the notice date | The next notice cycle lands directly on top of the Baltimore split-rate debate. Owners in the reassessed third should treat the 45-day window as the moment to correct a land-versus-improvement allocation (MB-F-1) |

| North Carolina | Varies by county | Nine counties are running FY27 on frozen values under SB 889; twelve counties completed 2026 revaluations. Which category a county falls in changes the entire appeal posture, and the county list has been unstable enough that a floor sponsor could not state it on the record (Issue 5) |

| New Castle County, DE | Annual; 2026 deadline was March 14, no retroactive relief | Post-reassessment, with the General Assembly having shifted burden from residential to commercial owners. Late filings hold to the next year. Only evidence submitted with the original appeal form is considered at hearing |

| New Jersey | April 1 or 45 days from the bulk mailing, whichever is later; May 1 for municipalities under municipal-wide revaluation or reassessment | Deadlines strictly enforced; a missed date bars the appeal entirely for the year regardless of the merits |

Three practices that apply across all of them.

Calendar the deadline from the notice date, not from memory. Most of the windows above run from the date of a valuation notice rather than a fixed date, and several jurisdictions have moved their dates in the last two years. Allegheny's move to October 1 is the example; there will be others.

Build the evidence file before you file, not after. New Castle County's rule that only evidence submitted with the original appeal form is considered at hearing is unusually strict, but the general principle holds everywhere: an appeal filed to preserve the deadline with the intention of developing evidence later is a weaker appeal than one filed complete. For commercial property, the file should include rent roll, operating statements, comparable leases, and, where an anchor has departed, the vacancy timeline.

Where an anchor pharmacy or big-box space has gone dark, the income approach is the argument. Issue 2's "The Pharmacy Box and Your Income Approach" laid out how assessors treat vacant anchor space and what comparable rents look like for large-format retail after a pharmacy exits. Note the update in this issue's Frontage coverage: Walgreens' closure pace has slowed materially under new ownership, and national shopping center vacancy has run near cyclical lows on historically low construction deliveries. Both facts cut against an owner arguing a distressed re-tenanting environment. An income-approach appeal in this market needs property-specific evidence, not a market narrative.

Watch line: Lackawanna's Nov. 14 certification and the rates that follow it, the first real test of whether a six-decade reassessment lands revenue-neutral in practice. Also: whether North Carolina publishes a definitive list of the nine SB 889 frozen counties.

Duplicate check: Issue 2 (Michigan May 31), Issue 3 (Cook County, New Jersey), Issue 5 MB-P-2 (Cook County rolling windows) and MB-F-1 (SB 889). This is the consolidated fall reference; it should be built table-first and positioned as a piece readers save.

Source: Cook County Assessor assessment and appeal calendar; CBIZ commercial real estate state property tax updates; Miller, Miller & Canby (Maryland); Genova Burns (New Jersey); Town Square Delaware; Lackawanna County reassessment reporting; Tucker Arensberg (Allegheny County).

Verification note: Every date in the table must be confirmed against the primary county or state source in the week of publication. Deadlines move, and a service piece that publishes a stale date does more damage than one that publishes nothing.