Delaware property tax appeals
Review the sourced process overview below, then get the Delaware DIY Appeal Kit with an evidence workbook, filing controls, official links, and an editable appeal letter in one PDF. No parcel-specific comps.
How a Delaware appeal actually works
Every statement below is cited to its primary source and shows the date we verified it. Where we could not confirm something from a primary source, we say so instead of guessing. Dataset last re-verified 2026-08-13.
Missed the main deadline? Delaware has 8 remedies most homeowners never hear about
County pages rarely surface these. Each one is a distinct legal route with its own clock.
Senior School Property Tax Credit (statewide)
Homeowners age 65 or over receive a credit against regular school property taxes of 50 percent, capped at $500, usable only against taxes on a primary residence. Domicile requirement: those establishing Delaware domicile on or after January 1, 2018 must have been legally domiciled in the State at least 10 consecutive years; those establishing domicile after December 31, 2012 but before January 1, 2018 need 3 consecutive years; those domiciled before January 1, 2013 qualify in the ensuing tax year. Property tax bill must be paid in full each year to qualify for the next year. Valid driver's license or state ID required per applicant. Once qualified, no annual re-application is needed. NOTE: the state page's HTML meta description is stale and still says '$400' — the visible body text and 14 Del. C. § 1917(c)(1)b. both say $500.
When:
primary source · verified
Disabled Veterans School Property Tax Credit (statewide)
Credit against 100% of non-vocational school district property tax on a primary residence. Requires 100% disability compensation from the U.S. Department of Veterans Affairs due to service-connected permanent and total disability based on individual unemployability, or a 100% disability rating, AND legal Delaware domicile for at least 3 consecutive years. Extends to a non-remarried surviving spouse who was a titled owner before the veteran's death and occupies the property as a principal residence. Cannot be claimed together with the Senior School Property Tax Credit. Enacted by HB 214 w/ HA 1, signed August 10, 2021, effective beginning 2022. Property tax bill must be paid in full each year to qualify in a subsequent year.
When:
primary source · verified
Sussex County Over-65 and Disabled Property Tax Exemption
Exemption applied to taxable assessment up to $229,000 of assessed value (raised from $12,500 by Ord. Nos. 3082 and 3083, both amended 3-25-2025, to track the reassessment). Over-65 track: must be 65 by June 30 of the current tax year and a full-time Sussex resident for the preceding 5 years as of July 1. Disabled track: totally disabled and a full-time Sussex resident for the preceding 5 years. Both: income other than Social Security cannot exceed $6,000 single / $7,500 married. Subject to the Sussex County Clean Hands Act — all taxes, user fees and sewer charges on every parcel owned must be paid in full before the deadline. Non-transferable on sale; new owners must re-apply.
When:
primary source · verified
Kent County Elderly / Disability Tax Exemption
Reduction in taxable assessment for persons 65 or older by May 31, and/or persons totally (100%) disabled with documentation. Income caps: single adjusted gross income not to exceed $18,000; combined for applicant and spouse residing together not to exceed $24,750; an additional $3,100 may be added per additional dependent for whom the applicant is the sole means of support. Must currently reside on the property and have done so as principal residence for the 12 months immediately prior to application, and have been a Delaware resident for the 5 years immediately preceding the tax year — both requirements waived for veterans 100% disabled from military service. IRS Form 4506T must accompany the application. Annual re-application required. Clean-hands condition applies. The dollar amount of the assessment reduction is NOT published by Kent County.
When:
primary source · verified
Sussex County Property Tax Subsidy
Income-based subsidy applying to the county portion of tax only. Requires full-time Sussex residency for the preceding 5 years as of July 1, 2025; annual income not exceeding $15,800 single or $20,000 married; applies to the first $16,000 of taxable assessment; liquid assets or real estate other than the home must be less than $15,000. Property owner must re-apply each year. Clean Hands Act applies.
When:
primary source · verified
Quarterly supplemental assessment appeals
A separate, recurring remedy for mid-year assessment increases, distinct from the annual appeal. Scope is limited: in an annual appeal the entire assessment may be challenged; in a supplemental appeal only the amount by which the assessment was increased that quarter may be challenged. NEW CASTLE: appeal dockets are ANNUAL / JAN / APR / JUL / OCT; the same board rules apply. KENT: appeals of supplemental (quarterly) increases must be filed within 30 days of notification of the increase, with published filing deadlines of the last working day in November (Sept 1 bills), last working day in February (Dec 1 bills), and last working day in May (Mar 1 bills). SUSSEX: both appeal forms carry an Annual / Supplemental checkbox.
When:
primary source · verified
New Castle County year-round factual error correction and tax classification challenge
Separate from the March 14 appeal deadline, New Castle County accepts factual-error corrections (wrong square footage, bedroom/bath count, lot size, etc.) and tax-classification challenges at any time through an online SimpliGov workflow linked from the county Assessment page. This is the practical remedy for a homeowner who misses the annual appeal window on a data-accuracy issue.
When:
primary source · verified
New Castle County reassessment quality-control review (temporary)
A county-initiated, not taxpayer-initiated, correction mechanism. The New Castle County Office of Finance may conduct a quality control review of a parcel's new reassessed value where: a clerical, mathematical or factual mistake occurred; a nonresidential parcel valued at $300,000+ decreased from its prior value; a nonresidential parcel valued at $300,000+ changed by no more than 50% of the median nonresidential increase; or a nonresidential parcel's new value is at least 25% below its actual sale price in the 5 years preceding reassessment. Revisions made after a quality control review are themselves subject to the notice and appeal requirements of §§ 8312 and 8321 — meaning a fresh appeal right attaches. EXPIRES March 31, 2027.
When:
primary source · verified
What evidence wins in Delaware
All property is assessed at fair market value as of the county's most recent reassessment base date — NOT at a percentage of market value. Base dates: New Castle July 1, 2024; Kent July 1, 2023; Sussex July 1, 2023. Comparable sales must reasonably relate to that base date (Kent specifies sales from Jan 1, 2021–June 30, 2023 and appraisals valued Jan 1, 2022–June 30, 2023). Sussex requires 3–6 comparable sales, all listed on the form; New Castle caps discussion at 6 listed comps. Comparables not identified on the form are excluded, as are unidentified witnesses. Appraisals must be by a Delaware-licensed appraiser who appears at the hearing. Per Seaford, the income approach cannot stand alone and must be tested against another accepted approach. Boards cannot increase an assessment on appeal (New Castle rule).
primary source · verified 2026-08-12
The appeal ladder, in Delaware's own terms
- 1
County Assessment Office / Department or Office of Finance — informal review
Deadline: Not a uniform statutory step; availability and timing vary. KENT: an explicit 'Informal Appeal (Assessment Office Determination)' stage exists and is invoked on the same Assessment Appeal Form (INFORMAL APPEAL checkbox) under the same last-working-day-of-January deadline; if appellant and assessor agree, appellant signs a stipulation of value. NEW CASTLE: no standing informal stage, but factual-error corrections and tax-classification challenges may be filed year-round via the county's SimpliGov workflow. SUSSEX: no standing informal stage; a one-time referee/informal process was used in the 2025 reassessment cycle only. Exhausting informal review is NOT a prerequisite to filing with the Board of Assessment Review.
Clock starts: Receipt of assessment notice or annual assessment roll
No statewide statute creates an informal review stage; 9 Del. C. § 8311 addresses only Board of Assessment Review appeals. Kent's informal stage is published in the county's 'Appeal Procedures REVISED April 2025'. · primary source · verified 2026-08-12
Form: None assigned — KENT: 'Assessment Appeal Form' (Kent County Board of Assessment) with the INFORMAL APPEAL box checked. NEW CASTLE: no paper form — online factual-error/classification correction workflow. SUSSEX: none published. official form
primary source · verified 2026-08-12
Not confirmed from a primary source: No county publishes an informal-review fee. Absence of a published fee is not the same as a confirmed $0 fee; none of the three counties affirmatively states that informal review is free. Check the official page before relying on this. - 2
County Board of Assessment Review (New Castle, Kent, or Sussex)
Deadline: NEW CASTLE: March 14 of each year; appeal must be RECEIVED (email to BOARAppeals@newcastlede.gov or hand delivery) by 4:00 PM — postmark is expressly irrelevant. The 2026 deadline was March 14, 2026 and is CLOSED as of 2026-08-12; the county has published the next window as January 1, 2027 to March 14, 2027. (A one-time extension to March 31, 2025 applied only to the 2025-2026 reassessment year and must NOT be carried forward.) | KENT: last working day in January, 5:00 PM — postmark NOT accepted; i.e. January 31, or the last day of January if the 31st falls on a weekend. Affects the tax year beginning June 1. The 2026 window is CLOSED. Kent publishes this as a standing undated rule and warns 'Appeal Deadlines may change on Reassessment Years.' | SUSSEX: March 15, 4:30 PM — postmark NOT accepted; window opens in January. The 2026 deadline was March 15, 2026 and is CLOSED. (The one-time 2025 reassessment-year deadline was March 31, 2025 — do not carry forward.) | CRITICAL: 9 Del. C. § 8311(b)-(c)'s 'March 1 to May 31' is the Kent/Sussex board HEARING window, NOT the filing deadline.
Clock starts: Annual assessment roll / publication of notice under 9 Del. C. § 8312(a); for supplemental (quarterly) assessments, the date of the increase notice
9 Del. C. § 8311(a) (New Castle: 'Any person desiring to take an appeal shall prior to March 15 file written notice thereof with the Board'); 9 Del. C. § 8311(b)-(c) (Kent and Sussex boards hear appeals March 1 to May 31 of each year); 9 Del. C. § 8312(a)-(b); 9 Del. C. § 8313 (failure to appeal = liable for tax as assessed). Kent's January filing deadline and Sussex's March 15 filing deadline are county-published / board-rule based (Sussex BOAR Rules of Procedure Art. VIII § 1), not stated in § 8311. · primary source · verified 2026-08-12
Form: None — no Delaware county assigns a form number to its assessment appeal form. — NEW CASTLE: 'Residential Assessment Appeal Form — Board of Assessment Review of New Castle County' and 'Nonresidential Assessment Appeal Form'. KENT: 'Assessment Appeal Form' (Kent County Board of Assessment), plus a mandatory signed Residential or Commercial instruction sheet. SUSSEX: 'Residential Assessment Appeal Form — Board of Assessment Review of Sussex County' and 'Commercial/Industrial Assessment Appeal Form'. official form
primary source · verified 2026-08-12
Not confirmed from a primary source: Exhaustive check of all three counties' assessment pages, appeal forms, instruction sheets, board rules of procedure, FAQs and fee codes found NO published assessment appeal filing fee. New Castle historically was reported to charge a fee; no current fee amount is published anywhere on newcastlede.gov and I will not repeat an unconfirmed historic figure. The only fee found in New Castle's appeal apparatus is a discretionary charge for copies of the County's own exhibits. Absence of a published fee is not a confirmed $0 — confirm by phone with the county assessment office before relying on it. Check the official page before relying on this. - 3
Superior Court of the State of Delaware (county of residence)
Deadline: 30 days by POSTMARK date after receiving written notice of the Board of Assessment Review's decision. Identical in all three counties — this is a statewide statutory deadline, not county-varying. Note the postmark rule at this level is the opposite of the county-board level, where all three counties expressly reject postmark and require actual receipt. The board must certify its record to the Court within 20 days after service of the notice of appeal. Related: Sussex's board issues its written decision within 5 business days of the hearing; each board must notify the appellant in writing by registered mail within 30 days of its decision (9 Del. C. § 8312(b)). Review is on the record, though the Court may permit new or different evidence; the Court may affirm, reverse, modify, or remand, and its decision is final.
Clock starts: Receipt of written notice of the Board of Assessment Review's decision
9 Del. C. § 8312(c) · primary source · verified 2026-08-12
Not confirmed from a primary source: Delaware Superior Court publishes no numbered, assessment-appeal-specific Notice of Appeal form. Appeals from a Board of Assessment Review are commenced by a notice of appeal under the Superior Court Civil Rules; no standard fillable form for this specific appeal type was located on courts.delaware.gov. Confirm the required caption and content with the Prothonotary of the relevant county before filing. Check the official page before relying on this.Fee: $200.00 filing fee for an appeal from a 'Board of Assessment', plus a $10.00 Court Security Assessment Fee collected on all initial civil filings = $210.00 total. Certiorari is separately listed at $200.00 (plus the same $10.00). All filing fees are nonrefundable and do not cover Sheriff's service, which is paid separately to the Sheriff. A later request for a trial date carries a separate nonrefundable $150.00 fee. (statutory)
Del. Super. Ct. Civ. R. 77(h) (Superior Court Civil & Criminal Fee Schedule); Court Security Assessment Fee effective December 1, 2007 · primary source · verified 2026-08-12
Who has to prove what
Before the Board of Assessment Review: the taxpayer must present 'competent evidence' of 'substantial overvaluation' — 'proof of value by any techniques or methods which are generally considered acceptable in the financial community and otherwise admissible in court.' Sussex's board rules operationalize this: if the appellant fails to present competent evidence of substantial overvaluation, the board may deny the appeal without receiving further testimony, and Assessment need not justify its number at all. Sussex also screens applications pre-hearing for 'deficient filing' and can dismiss on the papers. On appeal to Superior Court, a materially harder standard applies: the board's decision 'shall be prima facie correct and the burden of proof shall be on the appellant to show that such body acted contrary to law, fraudulently, arbitrarily or capriciously.'
primary source · verified 2026-08-12
When values are set
Mandatory, not discretionary — this is a recent change. 9 Del. C. § 8306(b)(1): 'All real property must be reassessed by the county in which the real property is located at least once every 5 years.' § 8306(b)(2): each 5-year period starts on the date a county board of assessment adopts a § 8314 certification reflecting completion of a general reassessment. This was created by HB 62, 152nd General Assembly = 84 Del. Laws c. 162, approved August 9, 2023, following the Chancery Court's ruling in In re Delaware Public Schools Litigation, 239 A.3d 451 (Del. Ch. 2020) and the resulting consent decrees. The same act replaced the historic 'true value in money' standard with 'present fair market value'; 84 Del. Laws c. 412 (HB 403, approved Sept. 19, 2024) then refined § 8306(a) to 'fair market value as of the date of the most recent reassessment base year in the county.' New Castle has publicly committed to 'reassessments every five years going forward.'
primary source · verified 2026-08-12
How counties differ
NEW CASTLE — Reassessment COMPLETE. Values set by Tyler Technologies at 100% of fair market value as of July 1, 2024; submitted Feb 2025 and first effective for fiscal/tax year 2025-2026. The 1983 base year is RETIRED; the county states reverting to 1983 values 'is legally unsupportable.' A one-time informal review with Tyler ran November–December 2024 (~11,500 hearings), and the formal 2025 deadline was extended once to March 31, 2025 — the county warns not to carry that date forward. Annual deadline: March 14, 4:00 PM, received not postmarked, no extensions possible. 2026 window CLOSED; next window published as Jan 1 – Mar 14, 2027. Online filing via Tyler SmartFile (https://newcastledesmartfile.tylerhost.net/newcastlede_sf/), or email BOARAppeals@newcastlede.gov, or delivery to 87 Reads Way, New Castle DE 19720. No filing fee published. Non-attorney representation PROHIBITED for individuals; entities need a Delaware attorney or an employee. Board cannot increase an assessment. 2026 bills delayed to mid-November 2026, due December 31, 2026, pending SB 228 nonresidential QC review. Source: https://www.newcastlede.gov/390/Board-of-Assessment-Review and https://www.newcastlede.gov/181/Assessment. NOTE: nccde.org now redirects to newcastlede.gov and old page IDs no longer map to the same content. KENT — Reassessment COMPLETE. All taxable properties valued at fair market value as of July 1, 2023. The 1987 base year is RETIRED — Kent expressly lists 'Previous assessed value, established as 1987 base year' as INADMISSIBLE evidence. Kent publishes no explicit statement of the first tax year the new values applied; county rate charts show the reset between tax year 2023-2024 (.36) and 2024-2025 (.0572), i.e. the tax year beginning June 1, 2024 — INFERRED, not a county statement. Kent also publishes no explicit '100% of market value' ratio language. Annual filing deadline: last working day in January, 5:00 PM, postmark NOT accepted (Jan 31, or the last day of January if the 31st falls on a weekend) — this is NOT the March 1–May 31 statutory hearing window and is the single most common error to avoid. 2026 window CLOSED. Three-stage ladder: Informal (Assessment Office) → Stage 1 Hearing Officer (used mainly in reassessment years and the year after) → Stage 2 Board of Assessment Review → Superior Court within 30 days. NO online appeal portal — mail or in person only, 555 Bay Road, Dover DE 19901. No filing fee published. Appeals dismissed if there is a delinquent balance, if already appealed in the revaluation cycle absent new evidence, or if for prior years. CONFLICT: the April 2025 Appeal Procedures permit a non-attorney representative with written authorization disclosing contingency fees, while the residential and commercial instruction sheets (which the petitioner must initial and sign) say the petitioner must appear personally or be represented by a Delaware attorney-at-law. Source: https://www.kentcountyde.gov/My-Government/Departments/Finance/Assessment-FAQs. NOTE: co.kent.de.us now redirects to kentcountyde.gov. SUSSEX — Reassessment COMPLETE. Begun 2021 under the 2020 court order, conducted by Tyler Technologies, values set at 100% of fair market value as of July 1, 2023; values finalized June 30, 2025 and first applied to the 2025 tax year (FY2026 bills). Tax rate cut from 44.5 cents to 2.14 cents per $100. The 1974 base year is RETIRED — the county's own tables contrast a $4.42B '1974 Taxable Assessed Value' roll against a $91.57B '2023' roll, a 1,973% increase. One-time informal hearings with Tyler ran November 2024 – January 2025 (11,647 scheduled of 200,836 parcels; 6,082 value changes; 17,824 re-notices sent Feb 18, 2025), and the one-time formal reassessment appeal deadline was March 31, 2025 — do NOT carry forward. Standing annual filing deadline: March 15, 4:30 PM, postmark not accepted, per BOAR Rules of Procedure Art. VIII § 1; window opens in January. 2026 deadline was March 15, 2026 and is CLOSED. March 15, 2026 fell on a Sunday and Sussex published NO extension or Monday rollover — do not assume one. Late applications are received but not docketed until the next annual period, with any reduction effective only from the next tax year. NO online appeal portal — mail to PO Box 589 Georgetown DE 19947, in person at 2 The Circle, or email assessmentappeals@sussexcountyde.gov. No filing fee published. Must cite at least 3 and no more than 6 comparable sales; assessed values of other properties are expressly inadmissible; hearings limited to 15 minutes per side; written decision within 5 business days. DISCREPANCY: valuation date is July 1, 2023 in the BOAR Rules, both appeal forms and the reassessment page, but June 30, 2023 in one FAQ answer — use July 1, 2023. Source: https://sussexcountyde.gov/reassessment and https://sussexcountyde.gov/sites/default/files/PDFs/BOAR_RulesOfProcedure.pdf.
Delaware appeal deadline
Deadlines varyDelaware deadlines are set locally.
The deadline is almost always printed on the assessment notice your local assessor mails you. Use that date, it is the one that counts.
Are you missing a Delaware exemption?
Exemptions cut your bill before any appeal even starts, and most homeowners never claim all the ones they qualify for. Answer four questions:
Is your Delaware home over-assessed?
The whole appeal hinges on one comparison: your assessed value (from your tax notice) versus your home's market value (what it would sell for today). Put both in:
How to find your home's real market value (free) →
- Pull free estimates. Look up your address on Zillow (“Zestimate”) and Redfin (“Redfin Estimate”). Average them, algorithms run high or low, so two beats one.
- Find 3-5 real comparable sales. Same neighborhood, similar size, beds/baths, age, and condition, sold in the last 6-12 months. Recent sales (not listings) are the strongest evidence a board will accept.
- Adjust for differences. Knock value off comps that are bigger or renovated; add for ones that are smaller or dated, so you're comparing like-for-like.
- Compare to your assessment. If your assessed value sits clearly above that adjusted market figure, you have grounds to appeal.
One catch: some states assess at a fraction of market value (an “assessment ratio”). If your notice shows a ratio or an “equalized” value, compare your implied full value to market, not the raw assessed number.
How property tax appeals generally work
Most states follow the same basic path: your local assessor mails an assessment notice with a value and a deadline; you file an appeal (often called a protest, grievance, or petition) before that deadline; you present comparable sales of similar homes; and a local board reviews the evidence and can lower your value.
The exact form, deadline, and board can vary by county. Use the current assessment notice and the official sources linked above to confirm the controlling local requirements. The paid kit organizes that verification, the evidence, the filing steps, and your editable letter in one place.
Want to see the depth we build per state? Take a look at our Texas, Florida, and Georgia guides.