Montgomery County Property Assessment: How It Works and How to Appeal
Your Montgomery County property tax bill is based on an assessed value set by the state — not your purchase price. Here's how SDAT determines your assessment, why it may be wrong, and the step-by-step process to appeal it.
Edward Dumitrache
April 22, 2026
Your Montgomery County property tax bill is calculated using an assessed value set by the Maryland State Department of Assessments and Taxation (SDAT) — not the price you paid. That assessed value may be too high. If it is, you're overpaying taxes every year until you appeal. Here's how the system works and how to challenge it.
How SDAT Determines Your Assessed Value
Maryland uses a triennial reassessment cycle — every property in the state is reassessed once every three years. Montgomery County is divided into three groups. Each year, one-third of properties are reassessed. So your home is physically reassessed once every three years, regardless of whether the market has moved up, down, or sideways.
What SDAT looks at:
- Recent sale prices of comparable properties in your area
- Property characteristics: square footage, lot size, year built, bedroom/bathroom count, condition
- Any permits pulled for additions, renovations, or new construction
- Income approach for investment properties
SDAT assessors do not always physically inspect each property. In many cases, assessments are done as "drive-by" or desk reviews, which means condition and interior updates may not be fully captured.
The 10% annual cap: Maryland law caps how much your taxable assessment can increase each year at 10% — even if the full reassessment shows a higher jump. If your property was reassessed at a 30% increase, the taxable value phases in over three years, increasing by 10% per year. This cap is called the Homestead Tax Credit and applies only to your primary residence.
Assessment vs. Market Value: Why They Differ
Your assessed value and your home's actual market value are almost never the same number.
In a rising market, assessed values lag behind reality. SDAT's reassessment uses sales data that may be 12–18 months old by the time your new assessment is set. Montgomery County home prices rose 6.6% year over year in March 2026 — that kind of appreciation means assessments set in 2024 may already be meaningfully below current market value for many homeowners.
The practical implication: overpayment is rare in a rising market because assessed values typically run below actual market values. But it does happen, particularly when:
- Your home has condition issues (deferred maintenance, structural problems) not reflected in the assessment
- Recent comparable sales were distorted by a few outlier high prices
- Your property has unique characteristics that make it less valuable than the "typical" home SDAT used for comparison
- You purchased the property and the new assessment came in higher than what you actually paid
When to Consider Appealing
Appeal your assessment when:
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Your assessed value is higher than what you'd realistically sell for today. If SDAT says your home is worth $700,000 but comparable sales tell you it would list at $640,000, you have a legitimate appeal.
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You recently purchased the home and SDAT reassessed above your purchase price. An arm's-length sale is strong evidence of market value.
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Your home has condition issues not reflected in the assessment. SDAT assessors working from data and drive-bys don't see water intrusion, HVAC age, or deferred maintenance.
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Your assessment is materially higher than comparable properties on your street. Pull 3–5 comps from SDAT's own records. If you're assessed meaningfully higher than similar homes nearby, that inconsistency is grounds for appeal.
When NOT to appeal: If your assessed value is well below current market value, don't appeal — you'd potentially be inviting SDAT to increase your assessment.
How to Appeal Your Montgomery County Property Assessment
Maryland's assessment appeal process has three levels. Start at Level 1 and escalate only if needed.
Level 1: Supervisor's Level Appeal
Deadline: You have 45 days from the date on your notice of assessment to file a Level 1 appeal. This notice is mailed when SDAT reassesses your property (one-third of properties each year, in January).
How to file: Complete the appeal form included with your assessment notice, or download it from SDAT's website. Submit by mail or in person to the local SDAT office for Montgomery County.
What happens: An SDAT supervisor reviews your evidence and compares it to their data. You may have an informal meeting. Many appeals are resolved at this level — often a modest reduction if your evidence is solid.
What to bring:
- 3–5 recent sales of comparable properties (same square footage, similar condition, within half a mile if possible, within the last 6–12 months)
- Documentation of condition issues (repair estimates, inspection reports, photos)
- Your actual purchase price if you recently bought the home
- Any appraisal you have
Level 2: Property Tax Assessment Appeals Board (PTAAB)
If you're not satisfied with the Level 1 outcome, you can appeal to the PTAAB within 30 days of receiving the Level 1 decision. This is a formal hearing with a three-member board. Evidence rules are more structured, but you do not need an attorney.
Level 3: Maryland Tax Court
The final administrative level. If the PTAAB rules against you, you can appeal to Maryland Tax Court within 30 days. This is a more formal proceeding. At this level, many homeowners hire a property tax attorney or consultant, particularly for high-value properties where the tax savings justify the cost.
What a Successful Appeal Saves You
On a $700,000 property with a $50,000 reduction in assessed value:
- Montgomery County property tax rate: approximately $0.9321 per $100
- Tax savings: $50,000 × 0.009321 = ~$466 per year
- Over three years (until next reassessment): ~$1,400 in savings
On larger properties or bigger reductions, the math gets more compelling. Many professional tax appeal services work on a contingency basis — they take 30–50% of the first year's savings — so there's no out-of-pocket cost.
New Buyers: Does a Purchase Reset Your Assessment?
Yes — sort of. When you purchase a property, SDAT receives a notice of the sale. If your purchase price is significantly above the current assessed value, SDAT will typically reassess the property in the next reassessment cycle using your sale as evidence of market value.
This means if you bought a home that was assessed at $550,000 for $700,000, you should expect the assessed value to move toward $700,000 at the next triennial reassessment. The 10% annual cap slows how fast the taxable value can increase, but it will trend upward.
How Often Is My Home Reassessed in Montgomery County?
Every three years. Maryland divides all properties into three reassessment groups. The specific cycle for your property is on your SDAT record.
Between reassessment years, your assessed value doesn't change unless SDAT receives notification of a permit, subdivision, or other triggering event. Voluntary improvements like finishing a basement or adding a bathroom will be captured at the next reassessment when the permit is pulled.
Frequently Asked Questions
How do I appeal my Montgomery County property assessment?
File a Level 1 Supervisor's Appeal within 45 days of your assessment notice. Submit the form to SDAT's Montgomery County office with supporting evidence (comparable sales, condition documentation, appraisal). If unsatisfied, escalate to PTAAB, then Maryland Tax Court.
What is the deadline to appeal my property assessment in Maryland?
45 days from the date printed on your annual assessment notice. Missing this deadline waives your right to appeal for that cycle.
Does a new purchase reset my assessment in Montgomery County?
Not immediately, but SDAT uses sale prices as evidence at the next triennial reassessment. Expect your assessed value to trend toward your purchase price over the next one to two assessment cycles.
How often are homes reassessed in Maryland?
Every three years. Maryland uses a triennial cycle, with one-third of properties reassessed each January.
What is the 10% cap on property tax increases in Maryland?
Maryland's Homestead Tax Credit caps how much the taxable assessment on your primary residence can increase in any one year at 10%, even if the full reassessment shows a larger jump. This applies to owner-occupied primary residences.
Is it worth hiring a property tax appeal professional?
For properties valued over $600K–$700K with a significant overassessment, yes. Most work on contingency (percentage of first-year savings), so there's no upfront cost. For modest savings amounts, filing yourself at Level 1 is straightforward and free.
Related Resources
- Montgomery County MD Property Tax Rate (2026): What Homeowners Actually Pay
- How to Look Up Montgomery County Real Estate Records
- When Are Montgomery County Real Estate Taxes Due?
- The Real Cost of Buying a Home in Maryland
Wondering if your current assessment is accurate? I can help you pull comparable sales data and evaluate whether an appeal makes sense for your property. Get in touch.
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