Assessment Ratio
100% (but outdated base years)
Appeal Deadline
Varies by county (2026)
Official Form
Board of Assessment Review form
Risk of Increase
No
How Assessment Works in Delaware
Delaware nominally assesses at 100% of fair market value, but most counties use outdated base years (some decades old), meaning assessed values are far below current market value. The effective ratio depends on when your county last reassessed.
How to File in Delaware
File an appeal with your county Board of Assessment Review. Deadlines and procedures vary by county. Contact your county assessment office for details.
Step-by-Step
Delaware Appeal Process
Review your property assessment on the county's records.
Contact the county assessment office to discuss your assessment informally.
File a written appeal with the Board of Assessment Review by the county deadline.
Attend the hearing and present comparable sales evidence adjusted for the base year.
If denied, appeal to the Superior Court.
FAQ
Delaware Property Tax Appeal Questions
Why are Delaware assessed values so low?
Most Delaware counties haven't reassessed properties in decades. The assessed values reflect market conditions from the base year, not current values. This means your assessed value may be a fraction of your home's current market value.
Can my Delaware assessment increase on appeal?
No. Delaware generally does not increase assessments during the appeal process. Your assessment can stay the same or be reduced.
How do I compare my assessment to neighbors in Delaware?
Because of outdated base years, you should compare your assessment ratio (assessed value divided by market value) to similar properties in your area, rather than comparing raw assessed values.