AssessCheck

Maryland Property Tax Deadlines

Maryland’s calendar is unusual because the state controls the value side: the deadlines that matter to you are counted from the Notice of Assessment SDAT mails in your reassessment year, and from each decision that follows it. The 45 → 30 → 30 ladder is the spine of the year — but only for the roughly one-third of owners whose region is up for review.

For the other two years of your cycle, the standing mechanisms — the petition for review and the homestead credit’s July 1 test — are the dates that matter instead.

The triennial reassessment cycle

Maryland is the only state that assesses centrally at the state level: SDAT appraises all real property at 100% of market value and certifies the values to the counties, which set rates and bill. Real property has been reassessed on a three-year cycle since 1980 — about one-third of each county's properties each year. A NOTICE OF ASSESSMENT (typically mailed in late December for a January 1 date of finality) discloses both the old and new values, and an INCREASE is phased in over three years: a $30,000 increase adds $10,000 per year to the old value. Decreases take full effect immediately.

Anchor: the triennial reassessment cycle, with each county divided into three regions · Basis: rule tied to an event

The Supervisor appeal: 45 days

The first appeal — on value or classification — goes to the Supervisor of Assessments for the county within 45 DAYS of the notice's date (online filing is available through the state's own appeal form). The Supervisor or a designee holds the hearing and mails a final notice. Separately, in the two years of the cycle when no new assessment notice arrives, a PETITION FOR REVIEW may be filed at any time within three years of the last final notice — but on or before the date of finality for the next taxable year — and it is also heard by the Supervisor. And an owner whose deed was recorded between January 1 and June 30 may appeal within 60 days of the recording date.

Anchor: the date printed on the notice of assessment · Basis: rule tied to an event

The PTAAB appeal: 30 days

If the Supervisor's final notice does not bring relief, the appeal continues to the county Property Tax Assessment Appeals Board (PTAAB) within 30 DAYS of the final notice. The board schedules and holds its own hearing.

Anchor: the mailing date of the Supervisor's final notice · Basis: rule tied to an event

The Maryland Tax Court: 30 days

Either party — taxpayer or Supervisor — may appeal the PTAAB's final determination to the Maryland Tax Court within 30 DAYS of the decision. The Tax Court is the top of the administrative ladder: pro se representation is allowed, there is no filing fee, the postmark is the filing date, and the exhaustion of administrative remedies is required before it (counties are excepted).

Anchor: the date of the PTAAB's decision · Basis: rule tied to an event

The homestead credit and its July 1 test

Every county and municipality must limit taxable-assessment increases on a principal residence to NO MORE THAN 10% per year (some adopt less), and the State applies the same 10% limit to the state portion of the tax. The credit is applied against the tax on the increase above the limit — it does not change the market value. Eligibility: principal residence lived in at least six months of the year including July 1, no transfer of ownership, no owner-requested rezoning that raised value, no substantial use change. Apply ONCE, not yearly — new purchasers are mailed an application after the deed is recorded, and eligibility can be checked on the state's Real Property Data Search.

Anchor: the property's status as of July 1 of the application year · Basis: rule tied to an event

Billing in July or August

Once SDAT certifies the values, the local governments apply their own tax rates and mail the property tax bills in July or August of each year; billing and collection are administered by local finance or treasurer's offices. The assessment and the rate are therefore set by different levels of government — a Maryland appeal changes the value SDAT certified, not the rate the county set.

Anchor: the local billing cycle — bills are sent in July or August each year · Basis: rule tied to an event

The shape of a reassessment year (illustrative)

Illustrative sequence for a property whose region is reviewed with a notice dated late December 2026. Your own dates run from your notice.

  1. Late December 2026: the Notice of Assessment arrives, showing the old and new values and the phase-in.
  2. January 1, 2027: the date of finality — the value locks unless you appeal.
  3. Within 45 days of the notice date (~February 9, 2027): appeal filed with the Supervisor of Assessments, online or in writing.
  4. Spring 2027: the Supervisor’s hearing, then a final notice by mail.
  5. Within 30 days of the final notice: appeal to the county PTAAB if the first step did not bring relief.
  6. Within 30 days of the PTAAB decision: appeal to the Maryland Tax Court — no fee, postmark counts.
  7. July 1, 2027: the homestead credit’s residence test — six months of the year including this date.
  8. July or August 2027: your county mails the tax bill, applying its rate to the certified (and capped) assessment.

What this tells you: the appeal ladder is finished — all three steps — before the first bill of the year even arrives. Waiting for the bill to decide whether to appeal is waiting too long; the window closed months earlier.

What it does not tell you: your county’s exact billing date and rate (set locally each spring), or the phase-in amounts for your property — those are on your own notice and the Real Property Data Search.

Where the processes are explained

Sources