Travis Bunn
Founder, AppealDesk · Published March 27, 2026 · Updated August 25, 2026
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Updated August 2026
For most of the twenty-first century, a home in Sussex County was taxed on a value the county last calculated in 1974. New Castle County's numbers dated to 1983, and Kent County's to 1987. In 2020, the Delaware Court of Chancery ruled in In re Delaware Public Schools Litigation that all three counties' decades-old base-year assessment methodologies violated the state's Uniformity Clause and True Value Statute, and by 2021 each county had agreed to a court-supervised general reassessment. Kent County's reassessment took effect for tax year 2024. New Castle and Sussex Counties followed for tax year 2025, mailing tentative new values in November 2024. For the first time in a generation, homeowners across the state opened an envelope with a number that reflected something close to today's market instead of a decades-old snapshot.
That correction was overdue, and by the numbers above, decades overdue. It also was not gentle: assessed values frozen for 37 to 50 years jumped to current fair market value in a single step, all at once, statewide. None of that changes how your mortgage escrow account works. Under Regulation X, your servicer still runs one analysis a year, on your loan's own anniversary, paying whatever the county bills and adjusting your payment only when it sees the new number. A reassessment landing on the county side and an escrow analysis landing on your loan's side are two separate clocks, and a value dispute working its way through your county's Board of Assessment Review pauses neither one.
Check your property record and relevant sales, then confirm the current local appeal window.
Delaware assesses at a nominal 100% of fair market value under 9 Del. C. Section 8306(a), which means there is no fractional ratio to soften an inflated number. Whatever the county says your home is worth is exactly what you are taxed on, dollar for dollar. In a state with a lower assessment ratio, an appraisal error gets diluted before it reaches your bill. In Delaware, it does not.
But "over-assessed" means something different here than it does in a state that reassesses every year or two. Your new number is not the product of decades of gradual market drift away from a figure everyone had already scrutinized. It is the output of a compressed, contracted mass-appraisal project that tried to model tens of thousands of properties against 37 to 50 years of unaddressed market change, all valued to a single date. That kind of project is more prone to individual-property errors, wrong square footage, wrong condition grade, a comparable sale that does not actually match your home, than an incremental annual reassessment tends to be. The fact that your county was right to reassess does not mean your specific new number is right. Those are two separate questions, and only the second one is what a Board of Assessment Review appeal is for.
Delaware's appeal path is short compared to many states, but the deadlines and format differ sharply by county:
If you filed in a county still working through its reassessment-year backlog, plan for your case to sit for months before the Board even reaches it. Nothing about that wait changes what your escrow account pays in the meantime.
Review the notice, filing instructions, and evidence requirements before ordering a packet.
Federal law, not Delaware law, governs your escrow account. Under Regulation X, 12 CFR 1024.17(c)(3), your servicer must analyze your escrow account once per computation year, a twelve-month cycle tied to your loan, not to your county's Board of Assessment Review calendar. That analysis pays whatever bill the county treasurer sends and projects the next one from it. It does not ask whether a BOAR appeal is pending, and it does not check whether your county has worked through its backlog. It simply pays the roll as it currently stands.
So if you filed your appeal in March, your hearing does not land until many months later because thousands of neighbors filed the same year, and the Board does not rule until sometime after that, your escrow account has already funded at least one full tax cycle at the disputed, newly reassessed number, quite possibly more than one.
Say a New Castle County homeowner opens her November 2024 notice and finds a new value of $299,000, Delaware's statewide median, on a home that had been assessed at a fraction of that under the county's 1983 base year. At the nominal 100% ratio, $299,000 assessed equals $299,000 taxed; at Delaware's 0.53% effective rate, that is roughly $1,585 a year, or about $132 a month if it were spread evenly. (Rates vary by school district and municipality, so treat this as illustration, not a quote.) She believes recent comparable sales support something closer to $269,000, so she gathers them and files with the New Castle County Board of Assessment Review before the March 15 deadline. She is one of roughly 5,200 New Castle homeowners who formally appealed that year. Her hearing does not happen until the following spring, and the Board does not rule until several weeks after that.
A homeowner who did everything right, filed on time and brought real comparables, still spent more than a year funding a disputed value through escrow before any of it reached her mortgage payment. That gap is the entire reason this article exists.
Check the taxable value, exemptions, and applicable dates before estimating a possible tax reduction.
Whichever level finally rules in your favor, the mechanics from there are the same. The county updates the roll with the corrected value, the treasurer issues a corrected tax bill, and none of that touches your monthly payment on its own. Your servicer has to see it. Three federal rules in 12 CFR 1024.17 control what happens next:
If your case sat in a reassessment-year backlog for months or went on to Superior Court, do not assume your servicer is tracking any of it. Nobody at the escrow department is watching your county's Board of Assessment Review docket for you. The corrected bill from the treasurer is the only document that moves your payment, so keep a copy of the Board's decision and the revised assessment, and send both the moment they arrive.
Delaware has just three counties, Kent, New Castle, and Sussex, and each is now on its own five-year reassessment clock under 9 Del. C. Section 8306 as amended by House Bill 62 in 2023. Each county's clock starts when its Board of Assessment adopts a Section 8314 certification that its general reassessment is complete, so Kent's clock, started at its 2024 completion, points to a next mandatory reassessment around 2029, while New Castle's and Sussex's clocks, started at their 2025 completions, point to around 2030. Filing deadlines and hearing calendars differ by county too: New Castle requires appeals filed prior to March 15, while Kent and Sussex hear appeals from March 1 to May 31 or until a reassessment year's full docket clears. Confirm the exact date on your own notice and your specific county's current procedure before you file.
Not by itself. A large jump reflects your county catching up to a fair-market-value standard it had not applied in 37 to 50 years, which is exactly what the 2020 Court of Chancery ruling and the 2023 reassessment law were designed to force. Whether your specific new number is accurate is a separate question, one about whether the mass-appraisal model got your home's characteristics and comparable sales right, and that is what a Board of Assessment Review appeal is for.
No. Your servicer pays whatever bill the county treasurer sends regardless of where your appeal sits in the queue. New Castle County received roughly 5,200 formal appeals from its 2025 reassessment and had worked through only a fraction of them by October 2025, but none of that backlog pauses what your escrow account funds each cycle.
No. Under 9 Del. C. Section 8312(c), Superior Court review is deferential: you have to show the Board acted contrary to law, fraudulently, arbitrarily, or capriciously, not simply that you disagree with its conclusion. Bring your strongest comparable-sales evidence to the Board hearing itself; that is the level built for a fresh look at the facts.
Under 9 Del. C. Section 8306 as amended by House Bill 62 in 2023, every county must reassess at least once every five years, and each county's five-year clock runs independently, starting when its Board of Assessment certifies that county's reassessment complete. Kent's clock started with its 2024 completion, pointing to a next mandatory reassessment around 2029. New Castle's and Sussex's clocks started with their 2025 completions, pointing to around 2030.
Not immediately. The county has to update the assessment roll and issue a corrected bill, and your servicer has to see that bill, typically at your next scheduled escrow analysis under 12 CFR 1024.17(c)(3). You can send the corrected notice and ask for an early analysis under 1024.17(f)(1)(ii); servicers are permitted, though not required, to run one. Once your servicer catches the correction, any resulting surplus of $50 or more must be refunded to you within 30 days under 1024.17(f)(2)(i), provided you are current on the loan.