How do I appeal an added assessment in New Jersey?

An added assessment is New Jersey's mechanism for taxing improvements that were completed after the October 1 valuation date — most often new construction, an addition, or a finished basement that the regular assessment did not capture.

What it is. Under the Added Assessment Law, N.J.S.A. 54:4-63.1 et seq., when a structure is erected or improved after October 1, the assessor adds the value of that improvement, prorated for the number of months it was complete during the tax year. You receive an added-assessment bill (typically in October, payable November 1) separate from your regular bill.

The deadline is December 1, not April 1. Added (and omitted) assessment appeals follow a different calendar. The NJ Division of Taxation directs that these appeals are filed on Form AA-1 by December 1 of the year the added assessment is made; the Division guide notes added/omitted appeals "are heard between the Dec 1 filing deadline and Jan 1."

Direct-to-Tax-Court threshold is $750,000. Per the NJ Division of Taxation: "If the aggregate assessed valuation of the property exceeds $750,000, the appeal may be made directly to the Tax Court of New Jersey." Otherwise you file with the County Board of Taxation.

What to challenge. You can dispute (1) whether the improvement was complete on the proration date claimed, (2) the number of months prorated, or (3) the value assigned to the improvement. Comparable sales of similar improved properties and contractor records (permits, completion dates) are the core evidence.

Practical note for new buyers and builders. If you bought new construction or finished a major project, watch for an added-assessment notice in the fall — it is easy to miss because it arrives outside the normal assessment cycle, and the December 1 deadline is firm.