To appeal a Montgomery County property tax assessment, file with Maryland’s State Department of Assessments and Taxation (SDAT) within 45 days of the date printed on your Notice of Assessment. There is no filing fee, but the assessment is presumed correct and you carry the burden of proving otherwise. If the local review doesn’t give you the result you want, the case moves to a hearing before the Property Tax Assessment Appeal Board (PTAAB), and from there you can appeal to the Maryland Tax Court.
When You Can Appeal
Maryland reassesses each property once every three years. Your window to appeal depends on where you sit in that cycle.1Maryland reassesses every property once every three years rather than annually.
If your group was just reassessed, SDAT mailed you a Notice of Assessment around late December with a proposed new value. You have 45 days from the notice date to file a reassessment appeal. Miss that deadline and the new value is locked in for the full three-year cycle, so treat the date as fixed.
In the two years your property isn’t being reassessed, you can still challenge the value by filing a Petition for Review. The deadline is the first business day after January 1 for the tax year beginning July 1. This is the path to use when market conditions have shifted or you’ve discovered an error in your property record between reassessments.
How to File
For a reassessment appeal, use SDAT’s online portal with the notice number and control number from page one of your assessment notice, or mail the paper appeal form that came with the notice to the Montgomery County assessment office. The online filing gives you instant confirmation, which is worth something when a deadline is involved.
For a Petition for Review, download the form from SDAT’s website and mail it to the Montgomery County local assessment office. You’ll need your property account number, your own estimate of the property’s value, and the grounds for the challenge.
Build Your Case Before You File
The assessment is presumed correct. Walking in and arguing that the number feels too high will get you nowhere. You need evidence, and the kind that works falls into a few categories.
Check the Property Record First
Pull your property’s record card from SDAT’s online database and read every line against reality. Wrong square footage, the wrong number of bedrooms or bathrooms, a finished basement listed when yours is unfinished, lot dimensions that don’t match your survey — any of these inflates your value at the source. Factual errors are common and are among the easiest grounds to win on, often without any debate about market value at all.
Pull Comparable Sales
Recent sales of similar nearby homes are the strongest market evidence in most appeals. Look for properties that match yours on square footage, lot size, age, and condition, and that sold in the past six to twelve months. Three to five solid comparables are usually enough. SDAT’s own website lets you search Montgomery County property records and recent sales, which is the same data the assessors are working from.
Document Condition Problems
Structural issues, deferred maintenance, environmental problems, or awkward topography that cuts into marketability all support a lower value. Photographs and contractor estimates give those claims weight. A home with a failing foundation or significant water intrusion is not worth what a comparable home in good condition is worth, and the assessment should reflect that.
Consider an Appraisal
A USPAP-compliant appraisal from a certified residential appraiser is the most authoritative evidence you can bring, and also the most expensive. Residential appraisals typically run $450 to $1,400 depending on complexity. Worth it when your potential savings across the three-year cycle clear that cost; usually not worth it for a small dispute. If your case eventually reaches the Maryland Tax Court, both sides must exchange any written appraisals at least 10 days before the hearing.
What Happens After You File
Supervisor’s Level Review
A supervisor at the local assessment office reviews your appeal first. This stage is informal. The assessor looks at your evidence and may call to talk through the property. A lot of cases, especially the ones built on factual record errors, get resolved here. You’ll receive a notice of the result. If you’re satisfied, you’re done. If not, the case moves to the next level automatically — you don’t have to file anything new.
PTAAB Hearing
Unresolved cases go to a hearing before the Property Tax Assessment Appeal Board for Montgomery County. Board members are local residents appointed by the Governor; they are not SDAT employees. The hearing is more formal than the supervisor’s review but it is not a courtroom, and you don’t need a lawyer, though you can bring one.
You present your comparables, documentation, and any other evidence. The state’s representative presents the assessor’s position. Board members ask questions of both sides. If you hired an appraiser, they can testify. The board issues a written decision, generally within 30 days of the hearing.
One thing to know before you walk in: the board has authority to raise your assessment, not only to lower or sustain it. It’s rare, but it means you want to be confident in your evidence before pushing to this stage.
Maryland Tax Court
If the PTAAB decision still leaves you with a value you believe is wrong, you can appeal to the Maryland Tax Court within 30 days of the board’s determination. You cannot skip the PTAAB and go straight to Tax Court; the administrative appeal has to be exhausted first.
Filing costs nothing. A written petition postmarked within the 30-day window is timely. The petition must state that the value is erroneous due to overvaluation, that the assessment is disproportionate compared to similar properties, or that some other error exists. The court must hear and decide residential appeals within 90 days of the appeal being entered, unless a party requests an extension. The same burden of proof applies: you have to show the assessment is wrong or that the PTAAB made an obvious error, or the board’s determination stands.
Check Your Tax Credits Before You Fight the Value
An appeal challenges the assessed value. Credits reduce what you actually owe, regardless of value, and missing credits is one of the most common reasons Montgomery County homeowners overpay. Check these before or alongside an appeal.
Homestead Tax Credit
The Homestead Tax Credit caps how much your taxable assessment can rise each year. State law limits the cap to no more than 10 percent annually, and each county sets its own figure. If your market value jumped at reassessment, this credit phases the increase in rather than letting the full amount hit at once. You have to apply through SDAT, and the property must be your principal residence. Many homeowners are already enrolled, but if you recently bought your home, verify that the credit transferred or file a new application.
Homeowners’ Property Tax Credit
This income-based credit, sometimes called the “circuit breaker,” limits your property tax to a percentage of household income. To qualify, combined gross household income cannot exceed $60,000, and net worth excluding the home and retirement accounts must be below $200,000. The application deadline is October 1 each year, though filing by April 15 lets any credit apply to the initial July tax bill. For homeowners whose income qualifies, this credit can be worth more than a successful appeal.