AppealDesk

New Castle County Property Tax Appeal, Delaware

Travis BunnTravis Bunn·Updated July 24, 2026

New Castle County is Delaware's most populous county, with Wilmington serving as both the county seat and the state's largest city. Other major population centers include Newark, Middletown, and the historic town of New Castle. Property tax appeals are particularly important in New Castle County following a comprehensive reassessment in 2025 that updated property values from 1983 assessments to current market values, affecting over 214,000 properties and resulting in significant tax increases for many homeowners. The county's median home value is approximately $312,000 with an effective property tax rate of 0.76%, resulting in a median annual tax bill of $2,369, which is below the national median of $2,400 but represents the highest property tax burden among Delaware's three counties.

Notable cities: Wilmington, Newark, Middletown, New Castle

Median Home

$312,000

Tax Rate

0.76%

Annual Tax

$2,369

On the typical New Castle County home, valued near $312,000 at the county’s effective tax rate of 0.76%, an over-assessment of even 10% means you are overpaying year after year until you appeal it. Here is how to find out if yours qualifies.

2026 Appeal Deadline: March 14, 2026 by 4:00 PM

Under Delaware law, the annual deadline to file an appeal for the upcoming tax year is March 14th (the law states 'prior to March 15'). Appeals can be filed starting January 1, 2026 for the 2026-2027 tax year. Missing this deadline means you cannot appeal that year's assessment, but you can file again the following year. No extensions are granted.

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How New Castle County Assesses Property

100%of market value

Assessed by: New Castle County Office of Finance - Assessment Division

Assessment cycle: Comprehensive reassessment conducted in 2025 (first since 1983), with ongoing adjustments for new construction and improvements

Notices typically mailed: Tax bills typically mailed in mid-November (adjusted from traditional July mailing for 2025-2026 cycle)

New Castle County assesses all properties at 100% of fair market value as of July 1, 2024. This means your assessed value equals your property's market value with no reduction. For example: If your home's market value is $312,000, at Delaware's 100% assessment ratio your assessed value would be $312,000. At the county's effective rate of 0.76%, this results in approximately $2,371 in annual taxes (excluding school district and municipal taxes, which are calculated separately and added to your total bill).

The Appeal Process

Appeals are heard by the Board of Assessment Review. Appeals are heard by the independent 9-member Board of Assessment Review or its appointed referees. Hearings are informal but structured, typically lasting 15 minutes. You will present your evidence, and the Board will ask questions. Only evidence submitted with your original appeal form can be discussed. The Board can only affirm or reduce your assessment, never increase it.

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Step 1: Obtain the appropriate appeal form (residential or non-residential) from the New Castle County Assessment Division at 87 Reads Way, by calling (302) 395-5520, or downloading from the county website.

2

Step 2: Complete the appeal form, including your property information, parcel number, your opinion of the property's fair market value as of July 1, 2024, and the reasons you believe the assessment is incorrect. Attach all supporting evidence including comparable sales, appraisals, photos of defects, or repair estimates.

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Step 3: Submit your completed appeal form with all evidence by March 14, 2026 at 4:00 PM. Evidence submitted after the initial filing may not be considered at your hearing. You can file by mail, in person, email, or through the county's online portal.

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Step 4: After filing, the Board of Assessment Review will schedule your hearing. You will receive notice of your hearing date and time. Hearings are held at the Government Center at 87 Reads Way, New Castle, DE 19720. You will have approximately 15 minutes to present your case to a referee or the full Board.

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Step 5: At your hearing, present your evidence clearly and professionally. Only evidence submitted with your original appeal form will be considered. The Board can only affirm or reduce your assessment, they cannot increase it. The Board will issue a written decision by mail.

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Step 6: If you disagree with the Board's decision, you may appeal to Delaware Superior Court within 30 days of the date the written decision is mailed to you. This requires filing a formal legal appeal in court.

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Step 7: If your appeal is successful and results in a reduced assessment, your tax bill will be adjusted. If you already paid your taxes and the reduction results in an overpayment of $50 or more, you may request a refund from the county.

Required form: Residential Property Appeal Form or Non-Residential Property Appeal Form (available from Assessment Division)

Filing Methods

mail:Mail to: New Castle County Board of Assessment Review, 87 Reads Way, New Castle, DE 19720
in-person:Deliver to: New Castle County Government Center, 87 Reads Way, New Castle, DE 19720, Monday-Friday 8:00 AM to 4:00 PM
online:Online submission through New Castle County's online portal (recently made available)
email:Email to: assessment@newcastlede.gov (contact office to confirm acceptance)

Evidence to Bring

Comparable sales: Recent sales (within past 6-12 months) of similar properties in your neighborhood that sold for less than your assessed valueProfessional appraisal: Independent appraisal by a Delaware-licensed appraiser dated after July 1, 2023Photographs: Photos showing property defects, damage, or conditions that reduce valueRepair estimates: Contractor estimates for needed repairs or documentation of deferred maintenanceProperty characteristic errors: Documentation showing errors in the assessment record (square footage, number of rooms, lot size, etc.)

New Castle County Assessor Contact

New Castle County Assessment Division - Office of Finance

Phone: (302) 395-5520

Address: 87 Reads Way, New Castle, DE 19720

Website: https://www.newcastlede.gov/181/Assessment

Online Portal: https://www3.newcastlede.gov/parcel/search/

Hours: Monday through Friday, 8:00 AM to 4:00 PM

Tax Exemptions in New Castle County

Senior (Over 65) County Tax Exemption

Up to $173,000 reduction in assessed value

Reduces the assessed value of your property for county tax purposes if you are 65 or older.

Eligibility: Must be 65 before July 1, owner-occupant of primary residence, property assessed value of $676,000 or less, household adjusted gross income of $65,000 or less (excluding Social Security and Tier 1 Railroad Retirement benefits), and legally domiciled in Delaware for 10 consecutive years (3 years if moved between 2013-2017). Tax and sewer accounts must be current or on payment plan.Deadline: June 1, 2026

Senior School Property Tax Credit

$500 credit (50% of school taxes, up to $500 maximum)

State-funded credit that reduces school property taxes for seniors 65 and older.

Eligibility: Must be 65 or older by June 30 immediately prior to the tax year, property must be principal residence, and must have been a Delaware resident for 10 consecutive years (3 years if moved between 2013-2017). No income restrictions apply to this credit.Deadline: April 30, 2026

Disability Exemption (County and School Tax)

Up to $173,000 reduction in assessed value for both county and school taxes

Provides property tax relief for totally and permanently disabled homeowners on both county and school taxes.

Eligibility: Must be totally and permanently disabled, primary residence owner-occupant, and legally domiciled in Delaware for 10 consecutive years (waived for veterans disabled due to military service). Tax and sewer accounts must be current or on payment plan.Deadline: June 1, 2026

Disabled Veterans School Property Tax Credit

100% elimination of non-vocational school district property taxes (typically $1,500-$2,500 annually)

Complete exemption from school district property taxes for 100% disabled veterans.

Eligibility: Must receive compensation from the VA for a service-connected 100% permanent and total disability OR receive compensation at the 100% rate due to individual unemployability. Must be legal resident of Delaware for past 3 years and property must be primary residence. Cannot claim both this and Senior School Tax Credit.Deadline: April 30, 2026

Disabled Veterans County Tax Exemption

Full county property tax exemption (assessed value reduction varies by property value)

County-level property tax exemption for 100% disabled veterans, separate from the school tax credit.

Eligibility: Must have 100% VA-rated service-connected permanent and total disability or individual unemployability status. Residency requirement waived for service-disabled veterans. Must be primary residence.Deadline: June 1, 2026

New Castle County Appeal Statistics

Avg Reduction

$853

% Who Appeal

2.5% (over 5,300 appeals filed for 2025-2026 tax year, representing an 8,000% increase over historical average)

New Castle County Appeal Packet · $49

Comparable sales evidence, county-specific filing guide, and professional cover letter. Enter your address to get started.

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Frequently Asked Questions

What is the deadline to appeal my property taxes in New Castle County for 2026?
The deadline to file a property tax appeal in New Castle County for the 2026-2027 tax year is March 14, 2026 by 4:00 PM. Under Delaware law, appeals must be filed 'prior to March 15,' which effectively means March 14th. You can begin filing appeals on January 1, 2026. This is a firm deadline with no extensions granted. If you miss the March 14 deadline, you cannot appeal your 2026 assessment, but you can file an appeal the following year for the 2027 tax year. Appeals filed after the deadline will be held over to the next year with no retroactive relief available.
How do I file a property tax appeal in New Castle County online or by mail?
New Castle County now accepts property tax appeals through multiple methods. You can file online through the county's online portal, which was recently made available for appeals. You can also submit your appeal by mail to New Castle County Board of Assessment Review, 87 Reads Way, New Castle, DE 19720, or deliver it in person to the Government Center at the same address during business hours (Monday-Friday 8:00 AM to 4:00 PM). Email submissions may also be accepted at assessment@newcastlede.gov. Regardless of filing method, you must include your completed appeal form and all supporting evidence, as only evidence submitted with your original appeal will be considered at your hearing.
What is the Senior School Property Tax Credit worth in New Castle County?
The Delaware Senior School Property Tax Credit provides a credit of 50% of your school property taxes, up to a maximum of $500 per year. This is a state-funded credit available to homeowners age 65 or older by June 30 prior to the tax year, with no income restrictions. To qualify, the property must be your principal residence and you must have been a Delaware resident for 10 consecutive years (or 3 years if you moved to Delaware between 2013-2017). The application deadline is April 30, 2026. This credit is separate from the New Castle County senior exemption, and you can qualify for both programs simultaneously for greater savings.
What evidence do I need to support my New Castle County property tax appeal?
To support your property tax appeal in New Castle County, you should gather comparable sales data showing recent sales (within 6-12 months) of similar properties in your neighborhood that sold for less than your assessed value. Other strong evidence includes a professional appraisal by a Delaware-licensed appraiser dated after July 1, 2023, photographs showing property defects or damage, contractor estimates for needed repairs, or documentation proving errors in the assessment record such as incorrect square footage, number of bedrooms, or lot size. All evidence must be submitted with your initial appeal form by March 14, 2026. Evidence submitted after the filing deadline will not be considered at your hearing. Online estimates from sites like Zillow are not accepted as evidence, but can help you identify comparable sales.
What happens at a Board of Assessment Review hearing in New Castle County?
At your Board of Assessment Review hearing, you will have approximately 15 minutes to present your case to either a referee or the full 9-member Board. Hearings are held at the New Castle County Government Center at 87 Reads Way in New Castle. The process is relatively informal but structured, you'll present your evidence, explain why you believe your assessment is too high, and answer questions from the Board. Only evidence that was submitted with your original appeal form will be considered. The Board can only affirm your current assessment or reduce it; they cannot increase it. After reviewing all evidence, the Board will issue a written decision by mail. If you disagree with the decision, you have 30 days from the date it's mailed to appeal to Delaware Superior Court.
Can I appeal my New Castle County property taxes every year?
Yes, you have the right to appeal your property assessment every year in New Castle County, but you must file by the March 14 deadline each year for that year's assessment. Delaware law provides an annual appeal window from January 1 through March 14 for the upcoming tax year. Even if you appealed last year, you must file a new appeal form if you want to challenge the current year's assessment. However, if you have a pending appeal from a previous year that has not yet been resolved, you do not need to file a duplicate appeal. The appeal is free to file, handled by an independent Board of Assessment Review, and there is no penalty for filing even if your appeal is not successful.
How much can I save by successfully appealing my property taxes in New Castle County?
Successful property tax appeals in New Castle County save homeowners an average of $853 per year, according to recent data. Your actual savings depend on how much your assessed value is reduced and your property's location within the county, as different municipalities and school districts have different tax rates. For example, if you successfully reduce your assessed value by $50,000, and your combined county, school, and municipal tax rate is 1.5%, you would save $750 annually. With over 5,300 appeals filed for the 2025-2026 tax year following the comprehensive reassessment, many homeowners are finding significant overassessments. The savings continue every year unless your assessment increases again in a future reassessment, making a successful appeal a valuable long-term investment in reducing your housing costs.
What are the income requirements for the New Castle County senior property tax exemption?
To qualify for the New Castle County Over-65 Exemption, your household adjusted gross income must be $65,000 or less per year, excluding Social Security benefits and Tier 1 Railroad Retirement benefits. This exemption can reduce your assessed value by up to $173,000 for county tax purposes, typically saving $280-$320 or more annually. You must be 65 before July 1, own and occupy the property as your primary residence, have a property assessed value of $676,000 or less, and have been legally domiciled in Delaware for 10 consecutive years (3 years if you moved between 2013-2017). The separate Senior School Property Tax Credit has no income restrictions and provides a $500 credit, you can qualify for both programs if you meet the respective criteria. Applications are due by June 1, 2026 for the county exemption and April 30, 2026 for the school credit.

Official Resources

New Castle County Assessment Division - Official Website →

Official county assessment office website with information on assessments, exemptions, and appeal procedures.

New Castle County Parcel Search - Property Lookup Tool →

Search property records, view current assessments, tax bills, and ownership information for any New Castle County property.

New Castle County Board of Assessment Review →

Information about the Board of Assessment Review, appeal procedures, hearing schedules, and how to file an appeal.

Delaware Division of Revenue - State Tax Information →

State-level tax information and resources, including state property tax credit programs and forms.

New Castle County Tax Exemptions Information →

Detailed information about available property tax exemptions including senior, disability, and veteran exemptions with application forms.

For state-wide appeal information including Delaware's assessment ratio and deadlines, see our Delaware Property Tax Appeal Guide →

Considering professional help with your appeal? Compare pricing, coverage, and pros/cons in our Best Property Tax Appeal Services (2026) or browse side-by-side service comparisons →

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Sources: https://www.newcastlede.gov/181/Assessment | https://www.newcastlede.gov/390/Board-of-Assessment-Review | https://www.mydetax.com/property-appeals | https://www.appealdesk.com/appeals/delaware/new-castle | https://www.ownwell.com/trends/delaware/new-castle-county | https://www.newcastlede.gov/182/Tax-Exemptions | https://ptaconsumers.aarpfoundation.org/taxpayer-states/dealware/

Last verified: 2026-07-24