What Is the Best Evidence to Protest Property Taxes? Expert Guide (2026)

The best evidence to protest property taxes is recent comparable sales data showing similar homes sold for less than your assessed value. According to tax assessors and successful appellants, 3-5 comparable sales within 0.5 miles that sold in the last 6-12 months carry the most weight in hearings.

But comparable sales aren't your only weapon. This guide reveals all the evidence types that win appeals, ranked by effectiveness, plus exactly how to gather and present each type for maximum impact.

Evidence Ranked by Effectiveness

1. Comparable Sales Analysis (Most Powerful)

Why it works: Tax assessments are based on market value. Nothing proves market value better than what similar homes actually sold for.

What makes a good comp:

• Same neighborhood (within 0.5 miles ideal, 1 mile maximum)
• Similar size (±15% square footage)
• Same style (ranch to ranch, two-story to two-story)
• Similar age (±10 years)
• Same bedroom/bathroom count (±1)
• Sold within last 6 months (12 months acceptable)

How to present it: Create a grid showing your property vs. each comp with adjustments for differences. If your assessment is $450,000 but three similar homes sold for $380,000-$410,000, that's compelling evidence.

Pro tip: Exclude foreclosures and family transfers—assessors will dismiss these as "non-arm's length" transactions.

2. Assessment Errors (Quick Wins)

Why it works: Factual errors are indisputable. If the county has your home listed as 3,000 sq ft when it's actually 2,500 sq ft, that's an automatic win.

Common errors to check:

• Square footage: Measure it yourself or hire an appraiser
• Lot size: Check your survey vs. county records
• Bedroom/bathroom count: Finished attic ≠ bedroom
• Garage spaces: Carport listed as garage?
• Pool/features: Removed but still on record?
• Construction type: Frame vs. brick affects value

How to prove it: Survey documents, building permits, photos with measuring tape, professional measurements. One client found the county had an extra 500 sq ft on record—instant $40,000 reduction.

3. Property Condition Documentation (High Impact)

Why it works: Assessments assume average condition. If your property needs major repairs, that directly impacts market value.

Best condition evidence:

• Contractor estimates: Written quotes for repairs
• Inspection reports: Professional documentation of issues
• Dated photos: Close-ups of damage with timestamps
• Maintenance records: Showing deferred upkeep

Most impactful issues:

• Foundation problems ($15,000-50,000 impact)
• Roof replacement needed ($8,000-25,000)
• HVAC system failure ($5,000-12,000)
• Plumbing/electrical issues ($3,000-15,000)
• Water damage/mold ($5,000-30,000)

Example that worked: Homeowner showed $45,000 in needed repairs (roof, HVAC, foundation) with three contractor estimates. Assessment reduced by 12%.

4. Unequal Appraisal Analysis (The Ratio Test)

Why it works: Even if your assessment matches market value, it's illegal if neighbors are assessed at lower ratios.

How to calculate:

1. Find 5-10 similar homes in your neighborhood
2. Look up their recent sale price and current assessment
3. Calculate assessment-to-sale ratio for each
4. If yours is higher than the median, you have a case

Example:

• Your home: Assessed $400,000 / Bought $380,000 = 105% ratio
• Neighbor A: Assessed $350,000 / Bought $370,000 = 94% ratio
• Neighbor B: Assessed $320,000 / Bought $340,000 = 94% ratio
• Your assessment should drop to match the 94% neighborhood ratio

5. External Obsolescence Evidence (Location Issues)

Why it works: Negative location factors reduce property value but aren't always considered in mass appraisals.

Strong external evidence:

• Traffic counts: Increased traffic on your street
• Noise studies: Decibel readings from nearby highways/airports
• Crime statistics: Rising crime rates in your area
• School closures: Nearby school shut down
• Commercial encroachment: New gas station next door
• Environmental issues: Flood zone changes, pollution

How to document: Government reports, news articles, traffic studies, police statistics, photos showing the negative influence.

Evidence That Doesn't Work (Avoid These)

❌ Zillow/Redfin Estimates

Assessors dismiss these as "computer generated values." Use actual sales data instead.

❌ "I Can't Afford It"

Financial hardship isn't considered. Appeals are about market value, not payment ability.

❌ Purchase Price from Years Ago

What you paid in 2015 doesn't reflect current market value. Recent sales only.

❌ General Market Complaints

"The market is down" without specific comparable sales won't work.

❌ Petitions from Neighbors

Signatures don't influence value determinations. Data does.

How to Organize Your Evidence for Maximum Impact

The Winning Format

1. Cover summary: One page stating your current assessment, requested value, and key evidence points
2. Comparable sales grid: Professional table with adjustments
3. Property photos: Labeled and dated, showing condition issues
4. Supporting documents: Estimates, reports, errors documentation
5. Conclusion: Clear request with evidence summary

Presentation Tips

• Use tabs or dividers: Make it easy to navigate
• Number everything: "Exhibit A, Exhibit B" etc.
• Highlight key numbers: Assessment differences, repair costs
• Include photos: Visual evidence is powerful
• Stay factual: Let data tell the story

Gathering Evidence: Where to Find What You Need

For Comparable Sales

• County websites: Most have free property search
• MLS access: Through a realtor friend
• Zillow/Redfin: Good for finding sales, verify with county
• Public records: Courthouse has everything

For Property Data

• Your deed: Official property description
• County tax card: Shows what they think you have
• Building permits: Prove actual improvements
• Survey: Accurate lot size and dimensions

For Condition Evidence

• Home inspectors: $300-500 for professional report
• Contractors: Free estimates for repairs
• Your phone: Date-stamped photos
• Maintenance records: Shows ongoing issues

Evidence Quality Standards: What Assessors Accept

✅ Acceptable Evidence

• Closed sales from MLS or public records
• Licensed contractor estimates on letterhead
• Professional inspection reports
• Government documents (surveys, permits)
• Date-stamped photographs
• Certified appraisals

⚠️ Questionable Evidence

• Handwritten repair estimates
• Photos without dates
• Pending sales (not closed)
• Your own measurements (better than nothing)

❌ Rejected Evidence

• Zillow estimates
• Neighbor opinions
• Old sales data (>2 years)
• Foreclosure sales

Real Success Stories: Evidence That Won

Case 1: The Comp Crusher

Situation: Austin home assessed at $625,000
Evidence: Five comparable sales averaging $540,000
Result: Reduced to $560,000 (saved $1,300/year)

Case 2: The Error Finder

Situation: County showed 3-car garage, pool
Evidence: Photos showing 2-car garage, no pool
Result: $75,000 reduction (saved $1,500/year)

Case 3: The Condition Documenter

Situation: 30-year-old home, original everything
Evidence: $52,000 in contractor estimates
Result: 15% reduction (saved $750/year)

State-Specific Evidence Requirements

Texas

• Emphasize unequal appraisal (strong protection in law)
• Comps must be from same ISB (school district)
• Photos highly effective at ARB hearings

California

• Focus on decline in value (Prop 8 appeals)
• Need closed sales, not listings
• Base year value comparisons important

Florida

• Requires "clear and convincing" evidence
• Professional appraisals carry more weight
• Hurricane damage documentation crucial

New York

• Grievance forms require specific evidence citations
• Comparable sales grid mandatory in many counties
• Income approach accepted for rentals

Advanced Evidence Strategies

The Multi-Angle Approach

Don't rely on one evidence type. Combine:

• 3-5 comparable sales (primary)
• 1-2 condition issues (supporting)
• Any errors found (bonus)

The Neighbor Network

If multiple neighbors appeal with consistent comp data, success rates increase. Share research, present unified evidence.

The Time-Adjustment Strategy

If comps are 8-12 months old, adjust for market changes using the Case-Shiller Index or local MLS statistics.

Common Evidence Mistakes to Avoid

1. Too many comps: 3-5 best ones beat 20 mediocre ones
2. Emotional arguments: Stick to facts and numbers
3. Disorganized presentation: Makes strong evidence look weak
4. Missing deadlines: Best evidence worthless if late
5. Ignoring instructions: Follow county-specific requirements

DIY Evidence Gathering Timeline

Week 1: Pull assessment records, identify potential comps
Week 2: Visit/photograph properties, get contractor estimates
Week 3: Analyze data, create presentation
Week 4: Review, organize, file appeal

Total time investment: 8-12 hours over a month

The Bottom Line on Property Tax Evidence

The best evidence to protest property taxes is recent comparable sales data, but successful appeals often combine multiple evidence types. Focus on quality over quantity—three perfect comps beat twenty poor ones.

Remember: assessors see thousands of appeals. The ones with clear, organized, factual evidence win. Emotional pleas and unsupported claims lose. Let your evidence tell the story.

Frequently Asked Questions

Q: Can I use pending sales as evidence?
A: Generally no. Assessors want closed sales that represent actual market transactions. Pending sales can fall through or change price.

Q: How old can comparable sales be?
A: Ideally within 6 months of your assessment date. Up to 12 months is acceptable. Beyond that, market conditions may have changed too much.

Q: Do I need a professional appraisal?
A: Not required, but a $400-600 appraisal can be worth it for high-value properties or complex cases. Most residential appeals succeed without one.

Q: What if there are no recent comparable sales?
A: Focus on other evidence: condition issues, assessment errors, unequal appraisal compared to neighbors, or external obsolescence factors.

Q: Should I mention my evidence in the initial protest?
A: Yes, briefly. Say "based on comparable sales analysis" or "due to property condition issues" but save details for the hearing.