.Local property taxes are based on the assessed value of a home, which reflects size, amenities and neighborhood characteristics.
Building an addition will increase your home’s value and raise your property taxes, but you might not see an immediate increase since governments have different reassessment schedules.
Don’t build an addition without a permit to avoid higher taxes. Tax assessors might see the addition when they drive by or compare aerial photographs, or a neighbor might turn you in.
Even if you weren’t caught right away, uninspected work could be unsafe. You could also hit a snag if you didn’t get a construction permit and later wanted to sell your house.