New Castle County, Delaware property-tax rates and deadlines
Tax bills, payment rules, and valuation-review windows are controlled by the local jurisdiction and the governing state framework. The reviewed record below separates published figures from items that still require confirmation with New Castle County Office of Finance, Assessment Division.
Rate context
PublishedApproximately 0.1846% for the FY2027 unincorporated residential county rate, derived from the official FY2026 rate of $0.1575 per $100 and the approved FY2027 17.2% increase; municipal, school, and non-residential rates vary.
Statement mailing
PublishedWeek of July 21, 2026 for the current billing cycle; New Castle County announced that 2026 tax bills would be mailed that week and uploaded to Parcel Search.
Payment deadline
PublishedDecember 31, 2026 for 2026 property-tax bills; New Castle County extended the traditional September 30 deadline because of its reassessment quality-control review.
Valuation protest
PublishedJanuary 1 through March 14, 2027 for the 2027 annual assessment appeal; New Castle County's Board of Assessment Review publishes this filing window.
Do not assume a grace period.
The reviewed record identifies the payment timing above but does not establish a universal penalty schedule for this page. Late charges, interest, collection costs, tax-sale procedures, and lien or foreclosure timelines can depend on state law and the local collector’s process. If the deadline is close or a balance is delinquent, contact the tax collector directly and request the current payoff amount in writing.
Treat a published payment deadline as a hard operational date and retain your receipt or confirmation number.
From assessment to collection
01Valuation and notice
Review the assessment notice as soon as it arrives. The protest window may run from the notice date rather than from the payment due date.
02Statement and account review
Match the tax statement to the parcel or account number and confirm exemptions, assessed value, taxing units, credits, and balance.
03Payment confirmation
Use the official collector channel, then save the receipt, transaction reference, and date posted. A bank submission is not always the same as a county posting date.