Wilmington apartment buildings are now taxed on current market values set by New Castle County’s 2025 reassessment, the first since 1983, and buildings with five or more units are classed as non-residential, which puts them on a higher school tax rate than homes. An owner’s total bill comes from three levies on that one county value: City of Wilmington tax, New Castle County tax and the school district’s tax.
Why the 2025 reassessment happened
For roughly four decades, New Castle County taxed property on 1983 values. That ended after the Delaware Court of Chancery ruled in In re Delaware Public Schools Litigation (2020) that the state’s system violated the requirement to assess at true value. As the Delaware law firm Morris, Nichols, Arsht & Tunnell summarized in its analysis of the reassessments, New Castle and Sussex counties mailed tentative values in November 2024 for the 2025 tax year, and state law now requires reassessment every five years. Delaware Public Media has reported that the next statewide reassessment is expected in 2030.
Because the county’s values had not moved in decades, the reset could not shift every property equally: property types whose market values had grown faster than average take on a larger share of the total levy. That is one reason Wilmington’s council and state lawmakers spent much of 2025 and 2026 revisiting rates.
Three bills, one assessed value
Wilmington owners pay two separate bills. The City of Wilmington bills its own real estate tax, and New Castle County bills county and school taxes together. The city’s City Property Tax page lists the fiscal 2026 rates adopted after the reassessment:
- Residential: $3.7413 per $1,000 of assessed value
- Non-residential: $5.8276 per $1,000 of assessed value
Wilmington City Council approved those rates by an 8–5 vote in May 2025. City rates are set each budget year, so owners should confirm the current year’s figures on the city’s site before underwriting.
The school tax split and apartment buildings
The bigger change for apartment owners came from the school levy. In 2025 the General Assembly passed House Bill 242, which let New Castle County school districts set a higher rate for non-residential property than for homes for the 2025–26 tax year, with the non-residential rate allowed to run up to twice the residential rate. Apartment buildings with five or more units were placed in the non-residential class alongside commercial, industrial and utility parcels. Revised county bills went out in fall 2025, and the payment deadline for affected owners was extended to November 30, 2025.
A group of property owners challenged the split. On October 30, 2025, the Delaware Court of Chancery upheld HB 242 in Newark Property Association v. State of Delaware, as reported by Richards, Layton & Finger. In 2026, lawmakers passed House Bill 462, which extends the split-rate option for the 2026–27 school year but lowers the cap so the non-residential rate can be no more than 1.85 times the residential rate. Spotlight Delaware reported that Governor Matt Meyer allowed it to become law without his signature in August 2026.
Appeals and classification questions
The county’s assessed value drives all three bills, so it is the number to check first. New Castle County’s reassessment FAQ (November 2025) notes:
- The appeal window for 2025–26 values had closed; the next formal appeal period opened after January 1, 2026, with a March 14, 2026 filing deadline.
- Questions about a parcel’s tax class, such as whether a property is coded apartment, commercial or residential, go to the county Assessment Office.
- An owner who disagrees with the Board of Assessment Review can appeal to Delaware Superior Court within 30 days of the written decision being mailed.
Apartment owners should watch the county’s assessment page each winter for the next appeal window, and confirm their building’s classification, since a four-unit building and a five-unit building can land in different school tax classes.
What the new system means for owners
The practical effect is that a Wilmington building’s tax line is no longer a stable, decades-old number. For underwriting:
- Rebuild the tax estimate from the current county value and the current city, county and school rates, rather than relying on a prior owner’s bill.
- Model the school levy at the non-residential rate for any building with five or more units, and remember the split cap is set by the legislature year by year.
- Keep clean income and expense records; rental property owners typically support an assessment appeal with that operating data.
- Expect another full revaluation around 2030.
Our NOI calculator is a quick way to see how a higher tax line changes net operating income. For more on the local market, visit our Wilmington market page, or browse other Delaware apartment markets.
