Property Tax Appeal, Explained Like I'm a Homeowner

You just got your property tax assessment notice in the mail, and the number makes you wince. Maybe your assessed value jumped 15% while your neighbor's stayed flat. Maybe you know your home isn't worth what the county says it is. Whatever the reason, you're wondering: can I actually do something about this?

The short answer: yes. And it's probably easier than you think.

Let's walk through exactly how property tax assessments work, what an informal appeal actually means, and how you can prep a solid case.

How Property Assessments Actually Work

Every year (or every few years, depending on your state), your county assessor's office determines what your property is worth. This "assessed value" becomes the basis for your property tax bill.

Here's the basic formula:

Assessed Value × Tax Rate = Your Property Tax Bill

Most homeowners focus on the tax rate, but here's the thing: you can't change the rate. That's set by your local government. What you can challenge is the assessed value.

What Goes Into Your Assessed Value

Assessors look at a bunch of factors to determine your home's value:

The assessor doesn't visit every property every year. They often rely on:

• Mass appraisal models (think algorithms that estimate values)
• Public records (building permits, sales data)
• Occasional site visits

This means mistakes happen. Often.

The Two Paths: Informal vs. Formal

When you want to challenge your assessment, you typically have two options:

Each appeal path has distinct advantages and tradeoffs. Understanding these differences will help you choose the right approach for your situation. Most homeowners find success starting with the informal route—it's the faster, lower-risk option that often resolves issues without needing to escalate.

Most homeowners should start with the informal route. It's free, it's fast, and if you have a clear case, assessors often make adjustments without you needing to go formal.

What Success Actually Looks Like

Let's get real about expectations. A successful appeal doesn't always mean slashing your assessed value in half.

Here's what "winning" typically looks like:

Small Wins (Most Common)

• 5-10% reduction in assessed value
• Correction of factual errors (wrong square footage, outdated property features)
• Alignment with comparable properties in your neighborhood

Medium Wins

• 10-20% reduction when market conditions have clearly changed
• Temporary reductions during market downturns (these get reviewed annually)

Big Wins (Rare)

• 20%+ reductions when there's been a major error or significant property damage
• Complete reassessment when property records are substantially wrong

Let's do the math. Say your home is assessed at $2,000,000 with a 1.2% tax rate:

• Your annual tax: $24,000
• 10% reduction: Assessed value drops to $1,800,000
• Your new annual tax: $21,600
• Annual savings: $2,400

Over 5 years, that's $12,000 back in your pocket.

The DIY Reality Check: What Prep Actually Takes

Let's be honest about what's involved in building a credible appeal case. While it's certainly possible to do this yourself, the process is significantly more complex and time-intensive than most homeowners anticipate—and there are plenty of opportunities to make mistakes that can undermine your entire case.

Phase 1: Document Gathering (2-4 hours)

You'll need to hunt down and organize several critical documents, many of which aren't always easy to locate:

Required documents:

1. Your current assessment notice (including the detailed property card with all characteristics the assessor has on file)
2. Your property deed or complete closing statement
3. Recent professional appraisal if you have one (from refinance or purchase within 12 months)
4. High-quality photos documenting every relevant defect and condition issue
5. Proof of property characteristics (survey, building permits, contractor invoices)

Common roadblocks:

• County assessor websites can be difficult to navigate, and detailed property cards aren't always available online
• Your closing documents might be buried in email archives or physical filing cabinets
• Knowing which defects are actually relevant (vs. normal wear) requires market knowledge

Phase 2: Finding Proper Comparable Sales (4-8 hours)

This is where most DIY appeals fall apart. Finding truly comparable sales requires understanding appraisal methodology, accessing multiple data sources, and making judgment calls that can be technically challenged.

What you're trying to do:

• Identify 3-6 "arm's-length" sales (excluding family transfers, foreclosures, or distressed transactions)
• Match on location (ideally same subdivision), property type, size (within 15-20% GLA), age, condition, and lot characteristics
• Sales must cluster around your assessment date (requiring time adjustments if they don't)
• Document not just the sale price, but the property characteristics, condition, features, and any relevant circumstances

Why this is hard:

• Free sites like Zillow show sale prices but often have incorrect square footage (sometimes off by 10-20%)
• Determining if a sale was "arm's-length" requires checking deed records for family names, unusual terms, or quick flips
• If your neighborhood has few recent sales, you'll need to make location adjustments, which assessors routinely challenge
• Market timing matters: a sale from 8 months ago needs a time adjustment based on market trends you'll have to research and defend

Easy mistakes to make:

• Picking sales that seem "close enough" but differ in ways the assessor will immediately flag (different school district, busy road vs. quiet street, finished basement vs. unfinished)
• Missing non-arm's-length transactions (family sales, builder inventory, foreclosures) that will get thrown out
• Using list prices instead of actual sale prices
• Relying on automated valuation models (AVMs) like Zestimates, which assessors don't accept as evidence

For a detailed walkthrough of finding and adjusting comparable sales properly, see our complete guide to comparable sales—it's significantly more involved than most homeowners expect.

Phase 3: Making Adjustment Calculations (3-5 hours)

Even after you find good comparable sales, you need to adjust each one for differences from your property. This requires market research, mathematical precision, and defensible methodology.

Adjustments you'll likely need:

• Time adjustments (market movement between sale date and assessment date)
• Size adjustments ($/square foot differential, accounting for diminishing marginal value)
• Feature adjustments (bedroom/bath count, garage spaces, basement finish, lot size, updates/renovations, pool, etc.)
• Condition adjustments (comparing wear and tear, system age, renovation timing)
• Location adjustments if you had to go outside your immediate area

Where people go wrong:

• Using arbitrary percentages or "gut feel" instead of market-derived adjustments
• Over-adjusting (total adjustments >15-20% of sale price makes the comp questionable)
• Under-adjusting (ignoring meaningful differences that the assessor will point out)
• Failing to document the basis for each adjustment amount
• Not understanding paired sales analysis or depreciated cost methods

See our comparable sales guide for detailed adjustment methodology.

Phase 4: Evidence Packaging (2-3 hours)

Your evidence needs to be organized, professional, and easy for the assessor to review. This isn't just throwing screenshots in an email.

What you need to produce:

• A clean one-page executive summary with your requested value and key points
• A detailed comparable sales grid showing all properties, adjustments, and adjusted sale prices
• Individual comp sheets with photos, property details, sale information, and adjustment explanations
• A map showing your property and all comparables with distances
• Supporting documentation (property records, listing sheets, assessment cards for each comp)
• Condition documentation for your property with organized, labeled photos

Formatting challenges:

• Creating professional-looking exhibits without design software
• Ensuring all calculations are accurate and clearly shown
• Writing persuasively without sounding argumentative or emotional
• Matching your county's preferred format (some counties have specific requirements)

Total Time Investment: 11-20 hours (spread over several days)

And that's assuming you don't hit major roadblocks like:

• Limited recent sales in your area
• Difficulty accessing county property records
• Needing to make complex adjustments you're not sure how to calculate
• Discovering errors in your research that require starting over
• County-specific requirements you weren't aware of

The stakes: Get it wrong, and you've burned hours of work for nothing. Include weak comps or make adjustable mistakes, and you undermine your entire case—potentially worse than not appealing at all.

The Actual Process: What Happens Next

Once you submit your informal review request or formal appeal:

Common Questions Homeowners Ask

Q: Will appealing raise my taxes? A: In most states, no. Your assessed value can only stay the same or go down. Check your state's specific rules, but "upside risk" is rare and usually requires unusual circumstances.

Q: How often can I appeal? A: Typically once per year, during your county's designated filing period (often 30-90 days after assessment notices go out).

Q: Do I need to hire someone? A: For most residential appeals, no. Property tax consultants exist and work on contingency (they take 25-50% of your first-year savings), but you can absolutely DIY this.

Q: What if I just bought my home? A: Your purchase price is strong evidence of market value, especially if you bought in the last 6 months. Bring your closing statement.

Q: Can I appeal if I disagree with the tax rate? A: No. You're appealing the assessed value, not the tax rate. The rate is set by your local government through the budget process.

When NOT to Appeal

Be honest with yourself. Don't waste time appealing if:

• Your assessed value is already below recent comparable sales
• You recently did major renovations that legitimately increased value
• Your home sold recently at or above the assessed value
• You can't find any solid evidence supporting a lower value

Appeals work when you have a legitimate case backed by data. They don't work when you're just hoping for a break.

Your Next Steps

Here's your action plan:

1. Check your deadline: Look at your assessment notice or call your county assessor's office to find out when you need to file by
2. Decide your approach: Either commit to the 11-20 hour DIY process above, or use a service like AppealArc to handle the evidence preparation for you.
3. Start with informal: Request an informal review with online forms or by mail.
4. Submit your evidence: Send your one-page summary with your supporting documents
5. Follow up: If you don't hear back in 2 weeks, make a polite phone call

Why This Matters

Property taxes are often your biggest housing expense after your mortgage. While you can't control interest rates or insurance premiums going wild, you can ensure your property tax is based on an accurate valuation.

Thousands of homeowners successfully reduce their assessments every year. Most are just regular people who took an hour to gather evidence and make their case.

Ready to get started? AppealArc prepares for you a county-ready evidence pack with comparable sales, exhibits, and prefilled forms. Learn more about how we help homeowners like you.