Maryland's triennial reassessment, explained.

Every Maryland property is reassessed by SDAT on a three-year rotating cycle. In a fast-appreciating market, the increase can run double digits — sometimes 20%+ in a single notice. Here's how the cycle works and how to appeal.

1. The triennial cycle

The Maryland State Department of Assessments and Taxation (SDAT) administers the assessment system. Each county (and Baltimore City) is divided into three roughly equal geographic reassessment regions, and SDAT reassesses one region per year [1]. Over three years, every property in the state is reassessed once.

The new assessment becomes the basis for property tax bills issued by your county or city. If the market value has risen significantly since the prior assessment cycle, your reassessment notice will reflect that change — sometimes dramatically.

2. Reading your assessment notice

SDAT mails reassessment notices around the end of December for the new tax year beginning July 1. Key fields:

• New total full cash value. SDAT's estimate of fair market value.
• Prior assessment. What the property was assessed at in the prior cycle.
• Phase-in schedule. Maryland phases in increases over three years, so the year-one increase is one-third of the total change, year two two-thirds, year three the full change [1].
• Homestead Credit applicability. If you've filed the Homestead application and the property is your principal residence, the taxable assessment growth is capped (typically at 10% per year statewide; lower in many counties) — see the Homestead guide [3].

3. How the Homestead Credit interacts

The Homestead Tax Credit caps annual taxable assessment growth on a principal residence at 10% statewide (lower in many counties), regardless of how much the full cash value increased [3]. This means:

• Your assessment can rise 30% in a cycle but your taxable assessment (the number your tax bill is calculated from) will only rise 10% in that first year.
• The remainder gets phased in over future years, still capped at the same annual percentage.
• Investment properties, second homes, and vacant rentals do not qualify — those bear the full increase.

4. The three-level appeal process

If you believe your assessment overstates fair market value, Maryland provides three escalating appeal levels [1][2]:

1. Supervisor's Level Review. First step — a review by the local SDAT supervisor. Often informal, can be done by phone, video, or written submission. Many disputes resolve here.
2. Property Tax Assessment Appeal Board (PTAAB). If you disagree with the supervisor's outcome, you have 30 days from the date of the supervisor's final notice to appeal to PTAAB [2]. Formal hearing in your county.
3. Maryland Tax Court. If you disagree with PTAAB, you have 30 days from the PTAAB decision to appeal to the Maryland Tax Court [2]. Functions like a court; many appellants engage an attorney at this level.

The property owner carries the burden of proof at every level [1][2]. You must show that the SDAT assessment is incorrect, not merely that you'd prefer it lower.

5. Deadlines that matter

• 45 days from receipt of a triennial or interim assessment notice to file your first-level appeal [1].
• First working day after January 1 for a Petition for Review in non-reassessment years (allows you to challenge an existing assessment that didn't get a new notice that year) [1].
• 30 days from the supervisor's notice to escalate to PTAAB.
• 30 days from PTAAB decision to escalate to Maryland Tax Court.

Missing any deadline forfeits the appeal at that level.

6. How to prepare for an appeal

Successful appeals rest on evidence. Bring:

• Recent comparable sales. 3–5 sold properties similar to yours that sold for less than your assessment. Closer in time and proximity is better. The MLS is your friend; a CMA from a real-estate professional often serves as the foundational document.
• Condition documentation. Photos of any deferred maintenance, defects, or condition issues that distinguish your property from the comps SDAT used. An inspection report can help.
• Recent purchase price (if applicable). If you bought recently for less than the assessment, that's powerful evidence — though SDAT may argue your purchase wasn't arm's-length.
• Adjustments worksheet. A clean adjustments table showing the comps' bed/bath/sqft/condition vs your home and the resulting indicated value.
• Income approach (for income-producing property). Rent rolls, expense statements, cap rates supporting a lower value.

For commercial or higher-value residential cases, engaging a property-tax attorney or appraiser is often worth the cost. The fee structure is often contingency-based: a percentage of the property-tax savings achieved.

This guide is general information for Maryland property owners and is not legal, tax, or appraisal advice. Property tax appeals are deadline-driven and fact-specific; consult a property tax attorney, certified appraiser, or qualified tax professional for advice on a specific case. Evan Kundrat is a Maryland-licensed real estate salesperson (Lic. #5003434) at Keller Williams Flagship of Maryland (Designated Broker: Barry Hess, Lic. #517943). Equal Housing Opportunity.

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