What is the property tax appeal deadline in Delaware?

Within 30 days of the assessment notice. Typical deadline month: March. Always verify the current deadline with your local assessor as dates can change.

What is the success rate for property tax appeals in Delaware?

An estimated 39% of property tax appeals in Delaware result in a reduction. This is based on Lincoln Institute research and state-reported data. Success rates are highest when appeals are supported by recent comparable sales.

2026 data Free guide Delaware

Delaware Property Tax Appeal Guide

Q: How do I appeal my property tax in Delaware?

In Delaware, file your appeal with the County Board of Assessment Review. The typical deadline is Within 30 days of the assessment notice. The filing fee is $0. Start by contacting your assessor informally, then follow the formal process if unresolved.

How to challenge your property tax assessment in Delaware — deadlines, process, and a savings calculator.

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By Kiznis Studio Editorial · May 2026

March

Typical Deadline

Filing Fee

~39%

Est. Success Rate

County Board of Assessment Review

Appeal Body

What This Data Tells Us About Appeals in Delaware

In Delaware, property tax appeals are filed with the County Board of Assessment Review. The typical window is Within 30 days of the assessment notice, with the deadline most commonly falling in March. Filing fees reported for this state are $0, and Lincoln Institute research plus state-reported data suggest roughly 39% of appeals result in some reduction when supported by comparable sales or documented errors.

Delaware has three counties (New Castle, Kent, Sussex) with different assessment schedules. New Castle County had a major reassessment in 2023. Appeals are driven by the gap between a parcel's assessed value and its actual market value — the calculator below turns that gap into an annualized dollar figure at your effective tax rate. The strongest evidence is three to five arms-length comparable sales from the past six to twelve months, plus documentation of any factual errors in the assessor's record (square footage, bedroom count, finished-basement status).

This guide is for informational purposes only and is not legal or tax advice. Deadlines, filing fees, success rates, and procedures vary by county within Delaware and can change year to year. Always verify the current rules with your local assessor's office — or a licensed attorney or tax professional — before filing. Source: Delaware Division of Revenue.

Appeal Deadline

Within 30 days of the assessment notice

Appeal Body: County Board of Assessment Review

Step-by-Step Appeal Process

1
Review your assessment from the county Board of Assessment
2
File a written appeal with the county Board of Assessment Review
3
Attend a hearing and present comparable sales or an independent appraisal
4
If denied, appeal to the Superior Court of Delaware

Delaware-Specific Notes

Delaware has three counties (New Castle, Kent, Sussex) with different assessment schedules. New Castle County had a major reassessment in 2023.

Source: Delaware Division of Revenue

Assessment Savings Calculator

Estimate whether an appeal is financially worthwhile and your potential annual savings.

Current Assessed Value ($)

Estimated Market Value ($)

Effective Tax Rate (%)

Find your rate on your tax bill or the county website

Frequently Asked Questions

How do I appeal my property tax in Delaware?

File with the County Board of Assessment Review. Within 30 days of the assessment notice. Start by requesting an informal review with your assessor, then follow the formal process outlined above if the issue is not resolved.

What is the Delaware property tax appeal deadline?

Within 30 days of the assessment notice. The typical deadline month is March. Always confirm the exact date with your local assessor's office, as deadlines can change year to year.

Do I need an attorney to appeal property taxes in Delaware?

No. Most homeowners successfully appeal without legal representation, especially at the initial administrative level. The process is designed to be accessible to ordinary homeowners.

What evidence is most effective for property tax appeals in Delaware?

Recent sales of comparable homes (3–5 "comps" from the last 6–12 months) that sold for less than your assessed value are the strongest evidence. An independent appraisal ($400–$800) is the gold standard. Property data errors (wrong square footage, extra rooms) are also persuasive.

Disclaimer: This guide is for informational purposes only and does not constitute legal or tax advice. Appeal deadlines, procedures, filing fees, and success rates vary by county within Delaware and change over time. Always verify current rules with your local assessor's office or a licensed attorney before filing. Success rates are estimates based on Lincoln Institute of Land Policy research and state-reported data — individual results vary.

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