After a property tax reassessment, a lawsuit, and potentially an appeal, residents of New Castle County will soon receive their final property tax bill for 2025.
The county is set to mail revised property tax bills during the week of November 24-28, 2025, sending copies to both property owners and, when necessary, their mortgage companies.
Per a bill passed in October, taxes for this year are due by December 31, 2025.
Residents can also check their tax contributions through New Castle County’s parcel search page.
If you’ve already paid the original bill sent out in July, that payment should be reflected in the adjusted bill you’re receiving in November.
If your new bill shows an amount greater than $50, you can request a refund. It raises a question—if the mortgage company is liable for the payment, who gets the refund?
If you decide not to request a refund, that amount will be directed towards either your 2026 sewer bill or your property taxes for 2026.
If you haven’t yet made your payment, you can set up a payment plan, which is expected to be paid in three equal installments due by December 31, 2025, February 27, 2026, and April 30, 2026.
Additionally, late school tax penalties in New Castle County are capped at 1% monthly.
The period to appeal this year’s assessments is already over. However, there will be a new window for 2026 assessments from January 1 to March 14, 2026.
The county has also addressed questions regarding the assessment process, particularly concerns about its legitimacy and the idea of reverting to the assessment values from July 1, 1983.
- Returning to the 1983 figures would essentially repeat the unconstitutional practices that led to all three Delaware counties reassessing their properties in the first place.
- This approach would violate a court decision and a resolution reached with plaintiffs in a recent lawsuit, creating valuation disparities and potentially conflicting with the Uniformity Clause of the Delaware Constitution. It contradicts several sections of Titles 9 and 14 of the Delaware Code.
- Operationally, it would undermine the budgets and functioning of counties and local school districts. Delaware law aims to correct assessment errors and offers various options for taxpayers to challenge assessments. Taxpayers may engage in an informal appeals process with the county’s third-party reassessment vendor in November and December 2024 and can utilize the statutory assessment appeals process, including appealing to the Delaware Superior Court. There are also opportunities to request changes or contest classifications through available administrative remedies. Reverting to 1983 valuations would ignore substantial options available for property owners to address their concerns regarding assessed values and tax obligations.
