How the added assessment works
Say an addition is finished in June. The assessor can value the house as of July 1 and add a prorated assessment for July through December (N.J.S.A. 54:4-63.3). From the next year on, the higher assessment is part of your regular tax bill.
Which projects are most likely to change it
Work that adds living space, like an addition or a finished basement, is the most likely to raise an assessment, because it changes what the house is. Replacing things that already exist, like new cabinets or a new vanity, is less likely to. Your municipal tax assessor makes the call.
How the assessor finds out
A construction permit is a public record of the work (N.J.A.C. 5:23-2.14). Skipping the permit to avoid taxes is a bad trade: unpermitted work can surface at sale, and the town can require it opened up for inspection. See do you need a permit in NJ.
MHG Contracting is a family-owned contractor at 2145 Nottingham Way in Hamilton, NJ (NJ HIC #13VH13286900). Estimates are free: call (609) 712-2474.