DE HB412

Removes the March 1 deadline for filing property tax exemption applications in New Castle County, allowing applications to be filed at any time.

Establishes that exemptions are effective retroactively to the later of: when the property owner met the exemption criteria, or 3 years before the application date.

Requires New Castle County to determine and process property tax refunds for approved exemptions based on the effective date, using proration calculations for partial-year ownership, but excludes school taxes from refunds.

Creates a new proration formula for property tax when ownership transfers to an exempt entity during a tax year, calculated by dividing annual tax by 365 and multiplying by days the nonexempt owner held the property.

Mandates New Castle County review all exemption applications decided on or after January 1, 2017, within 18 months and process any refunds owed under the revised law.