AppealDesk

New Castle County Property Tax Appeal — Delaware

Rob HartleyRob Hartley·Updated February 9, 2026

New Castle County is Delaware's most populous county, home to the state's largest city, Wilmington, and major corporate centers. The county underwent a comprehensive property reassessment in 2026, updating property values from 1983 assessments to current market values, affecting over 214,000 properties.

Notable cities: Wilmington, Newark, Middletown, New Castle

Median Home

$252,800

Tax Rate

0.84%

Annual Tax

$2,154

Population

approximately 570,000

2026 Appeal Deadline: March 14, 2026

Appeals for the 2026-2027 tax year must be filed between January 1, 2026 and March 14, 2026. This is the standard annual deadline under Delaware law.

Property in New Castle County, Delaware — local tax assessment and appeal guide

How New Castle County Assesses Property

100%of market value

Assessed by: New Castle County Assessment Division

Assessment cycle: annual

Notices typically mailed: Spring (typically by mid-March)

Properties are assessed at 100% of their fair market value as of July 1, 2024. The assessed value equals the market value and is used to calculate property taxes by multiplying it by the applicable tax rate.

The Appeal Process

Appeals are heard by the Board of Assessment Review. You will have 15 minutes to present evidence before a referee or the Board. Only evidence submitted with your original appeal form can be discussed at the hearing.

1

Step 1: Obtain and complete the appropriate appeal form (residential or non-residential) from the County website

2

Step 2: Gather supporting evidence including comparable sales (up to 6), photos, repair estimates, or appraisal

3

Step 3: Submit the completed form with all evidence by March 14, 2026

4

Step 4: Attend your scheduled hearing (typically before a referee first, then possibly the full Board)

5

Step 5: Present your evidence within the allotted 15 minutes at the hearing

6

Step 6: Receive the Board's written decision by mail or email

7

Step 7: If unsatisfied, appeal to Delaware Superior Court within 30 days of the decision

Required form: Residential Assessment Appeal Form or Non-Residential Assessment Appeal Form

Filing Methods

mail:New Castle County Board of Assessment Review, 87 Reads Way, New Castle, DE 19720
in-person:Government Center, 87 Reads Way, New Castle, DE 19720 (Monday-Friday 8:00 a.m. to 4:00 p.m.)

Evidence to Bring

Comparable sales from January 1, 2022 to June 30, 2024Photos of property conditionRepair estimatesAppraisal from Delaware-licensed appraiserDocumentation of structural issues

New Castle County Assessor Contact

New Castle County Assessment Division

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 - Friday 8:00 a.m. to 4:00 p.m.

Tax Exemptions in New Castle County

Senior Citizen Exemption (65+)

Variable reduction based on income

Partial property tax exemption for residents 65 years or older

Eligibility: Must be 65+ before July 1, own and occupy the property, income limits apply ($65,000 for New Castle County residents)Deadline: June 1st prior to tax year

Disabled Exemption

Variable reduction based on income

Partial property tax exemption for disabled residents

Eligibility: Must be permanently disabled, own and occupy the property, meet income requirementsDeadline: June 1st prior to tax year

Senior School Property Tax Credit

$500 (as of 2022)

Credit against school property taxes for eligible seniors

Eligibility: Age 65+, own and occupy property as principal residence, meet income requirementsDeadline: April 30th

Official Resources

New Castle County Assessment Office →

Official county assessor website providing property assessment information, appeals process, and assessment policies.

Delaware Division of Revenue Property Tax Information →

State revenue department's official guidance on property tax procedures and regulations in Delaware.

New Castle County Property Search →

County's online portal for searching property records, assessments, and ownership information.

New Castle County Tax Information →

County finance department page with tax payment information and property tax resources.

New Castle County Appeal Statistics

% Who Appeal

Over 5,200 appeals filed for 2026-2026 (approximately 2.4%)

Check Your New Castle County Assessment

Enter your address to see if your New Castle County property is overassessed.

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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 appeal your 2026-2027 property tax assessment is March 14, 2026. Appeals can be filed starting January 1, 2026. You must submit the appropriate appeal form to the Board of Assessment Review by the deadline - no extensions are granted.
How do I file a property tax appeal in New Castle County online?
New Castle County does not currently offer online filing for property tax appeals. You must submit your appeal form by mail to 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 a.m. to 4:00 p.m.).
What is the senior property tax exemption worth in New Castle County?
Seniors 65 and older may qualify for a partial property tax exemption based on income. Additionally, the Senior School Property Tax Credit provides $500 off school taxes. To qualify, you must meet age and income requirements and apply by the June 1st deadline for exemptions or April 30th for the school credit.
What happens at a Board of Assessment Review hearing in New Castle County?
At your hearing, you'll have 15 minutes to present evidence supporting a lower assessment. You can only discuss evidence submitted with your original appeal form. The County may have a representative present to defend their assessment. After the hearing, you'll receive a written decision by mail or email.
What evidence do I need for a property tax appeal in New Castle County?
You'll need comparable sales from January 2022 to June 2024, photos showing property condition issues, repair estimates, or an appraisal from a Delaware-licensed appraiser dated after July 1, 2023. You can submit up to 6 comparable sales, and all evidence must be included with your initial appeal form.
Can I still appeal my 2026 New Castle County property tax assessment?
No, the deadline to appeal 2026-2026 assessments was March 31, 2026 (extended from the usual March 14th). If you missed this deadline, you cannot appeal your 2026 assessment but can file an appeal for your 2026-2027 assessment between January 1 and March 14, 2026.
How much did property values increase in the New Castle County reassessment?
The 2026 reassessment updated property values from 1983 levels to current market values as of July 1, 2024. Individual property increases varied widely based on location and property type. The county committed to revenue neutrality, adjusting tax rates to offset overall assessment increases.

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 →

← All Delaware property tax appeal info

Sources: https://www.newcastlede.gov/DocumentCenter/View/61292/FAQ-40---Comprehensive-10152025 | https://www.newcastlede.gov/181/Assessment | https://www.newcastlede.gov/232/Tax-Information-Forms | https://www.newcastlede.gov/390/Board-of-Assessment-Review | https://www.ownwell.com/trends/delaware/new-castle-county

Last verified: 2026-02-09