Delaware property tax: assessment, school tax and senior credit

How is a home assessed?

Each county assesses all property “at its fair market value as of the date of the most recent reassessment base year in the county” (9 Del. C. § 8306(a)). A county must reassess all real property at least once every five years (§ 8306(b)). The school district does not assess anything itself: it must use the county’s assessment list as the basis for its tax (14 Del. C. § 1912).

New Castle County has completed a general reassessment, and the law gave the county a special quality-control review of the new values. That review ended with revisions due by September 30, 2026 (9 Del. C. § 8345, which expires March 31, 2027). Read your assessment notice, because a new base year changes how your value compares with other parcels.

Who sets the rate?

County. The county government levies its own tax on the same assessment.

School district. Local school boards levy the school tax under 14 Del. C. Chapter 19. A school district located entirely in New Castle County may use different rates for residential and nonresidential property. The nonresidential rate must be at least the residential rate and no more than 1.85 times it (14 Del. C. § 1904(c)). New Castle County’s own residential and nonresidential classifications apply (§ 1904(d)). For the 2025-2026 year only, an earlier law let those districts reset rates with a ceiling of 2 times the residential rate (Laws of Delaware, Vol. 85, Ch. 135).

Municipality. Cities and towns tax inside their limits. The county senior exemption described below does not reduce taxes “levied within and by a municipality” (9 Del. C. § 8132(b)). Payotte could not read the adopted City of Wilmington rate in the official sources open to it, so take the current county, school and city rates from your tax bill.

How to estimate your bill

A quick check is: assessed value ÷ 100 × total rate per $100. The rate varies by school district and by whether you live inside a city, so here is a scale only. On a home assessed at $250,000, every $0.10 per $100 of rate adds $250 a year ($250,000 ÷ 100 × $0.10). Add the county, school and city rates from your bill to get the total. For prices, see home prices in Delaware.

Is there a homestead exemption?

Delaware’s relief for homeowners rests on two senior programs, both with narrow rules.

The school credit has a residency test. A person who established Delaware domicile after December 31, 2017 needs at least 10 consecutive years of legal domicile as of June 30 before the county fiscal year (14 Del. C. § 1917(c)). The application is due to the county by April 30 before the tax year, and the Department of Finance asks applicants to pay the property tax bill in full by the end of each tax year to qualify for the next year’s credit. The Department lists the New Castle County contact as (302) 395-5520.

Can you challenge your assessment?

Yes. In New Castle County the Board of Assessment Review hears appeals, and you must file written notice before March 15 (9 Del. C. § 8311(a)). The Board must give you at least 10 days’ notice of the hearing, and missing it counts as abandoning the appeal. If the Board rules against you, you may appeal to the county’s Superior Court within 30 days of the postmark of the decision notice (§ 8312(c)). The Board’s decision is presumed correct, and you carry the burden of showing it acted contrary to law, fraudulently, arbitrarily or capriciously. If a successful appeal reduces your assessment and you overpaid by $50 or more, you are entitled to a refund (§ 8311(d)).

When is it due, and what happens if you pay late?

New Castle County taxes are due July 1 (9 Del. C. § 8601(1)). After September 1, the county adds a penalty of 6% of the current charge plus 1% of the unpaid balance on the first of each month until it is paid (§ 8604(a)(1)). For New Castle County taxes covered by the reassessment review in § 8345, the law sets special 2026 dates: a statement mailed no later than November 16, 2026, payment due December 31, 2026, and the 6% plus 1% penalty after January 1, 2027. Check your own bill, because these dates apply only to taxes subject to that section.

A residential owner can ask for a payment plan if the property is the primary residence and the bill is $300 or more higher than last year’s. School taxes must then be payable in at least three equal installments with no interest or penalty if the owner pays on time (§ 8604(d)).

What to ask at closing

Property taxes are prorated at closing under your contract, so see closing costs in Delaware and your escrow account. Make sure the county has your mailing address: failing to receive a bill does not excuse late payment (§ 8602(c)).