New York law gives most assessment control to local assessors.

The one-page form that must be filed is called RP-425 and can be obtained from local assessors.

In individual cases, the local assessor often increases an assessment when major home improvements are made.

Assessments prepared by local assessors are used to distribute the property tax burden within individual municipalities.

Before a major project, homeowners should ask their local assessor how the change will be calculated.

To qualify, homeowners must file a short form with their local assessors.

But because it relies on public records, Zillow knows only as much about a house as the local assessor knows.

The local assessor and the head of the building department said they did not know how many were tear-downs.

The local assessor is entitled to a margin of error of 15 percent in his assessment.

She is a member of the Centre Party and has been a local lay assessor.