Delaware Property Tax Appeal Guides
Browse source-reviewed property tax appeal guides for Delaware. County deadlines, filing methods, and available records can differ by county and tax year.
Each published guide identifies the public sources used for its deadline and filing summary. Confirm current requirements with the official filing authority before submitting anything.
How Delaware assessment appeals generally work (state framework reviewed 2026-08-02 from official Delaware sources): Real property is assessed at fair market value as of the county's most recent reassessment base year, and each county must reassess at least once every five years. The county Board of Assessment Review hears administrative appeals. A person aggrieved by its decision may appeal to the Superior Court in the applicable county.
Delaware deadline framework: Annual assessment publication and appeal timing differ by county. New Castle County requires written notice before March 15; Kent and Sussex County boards generally hear annual appeals from March 1 through May 31. A supplemental assessment may be appealed within 30 days after notice.
Local variation in Delaware: New Castle, Kent, and Sussex Counties administer their own assessment offices, forms, filing channels, hearing schedules, and evidence rules. Municipal assessments may adopt the county roll or follow separate charter procedures.
Before relying on a date: Resolve the county and whether the disputed assessment is annual, supplemental, municipal, or reassessment-related, then verify the current notice, form, receipt deadline, submission channel, board rules, and hearing schedule.
State source: Delaware General Assembly, Delaware Code Title 9, Chapter 83 — Valuation and Assessment of Property, https://delcode.delaware.gov/title9/c083/sc01/. Reviewed 2026-08-02.
State source: New Castle County Board of Assessment Review, New Castle County Board of Assessment Review Rules, https://arden.delaware.gov/wp-content/uploads/2025/02/NCC-BOAR-Rules-2.13.2025-FINAL-VERSION-WITH-EFFECTIVE-DATE_202502131242276507.pdf. Reviewed 2026-08-02.
New Castle County: 2026 deadline guidance is 2026 annual assessment appeal deadline was March 14. Guide: https://fairpath.app/property-tax-appeal/delaware/new-castle-county
Source: Delaware General Assembly, Delaware Code Title 9 Chapter 83, https://delcode.delaware.gov/title9/c083/sc01/. Reviewed 2026-08-06.
Source: New Castle County, 2026 Formal Property Assessment Appeal Guide, https://www.newcastlede.gov/DocumentCenter/View/62987/NCC---Guide-to-Property-Assessment-Appeals. Reviewed 2026-08-06.
Source: New Castle County, Assessment Division and Parcel Search, https://www.newcastlede.gov/181/Assessment. Reviewed 2026-08-06.
Source: New Castle County, Board of Assessment Review, https://www.newcastlede.gov/390/Board-of-Assessment-Review. Reviewed 2026-08-06.
Source: New Castle County Office of Finance, 2026-2027 Annual Assessment Legal Notice, https://www.newcastlede.gov/DocumentCenter/View/26129/Legal-Notice. Reviewed 2026-08-06.
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