NISKAYUNA — An estimated 100 Niskayuna property owners filed for informal hearings on their property tax assessments last week, the first week for them to do so, officials said.

Niskayuna residents began receiving letters with their new assessments last week along with instructions on what to do if they wished to challenge them.

Town Assessor Amy Houlihan said Monday and Tuesday were busy days as residents called and asked about the numbers. Residents have until the end of the month to ask for the hearings.

“It hasn’t all been bad,” she said. “But, yes, we have gotten some who say theirs is too high.”

There are about 8,500 properties in the town.

The reassessment is the first for the town since 1998. Valuations had fallen below 60 percent.

The Town Board hired Amherst-based GAR Associates to conduct the reassessment last fall at a cost of $379,225.

GAR Associates is handling virtually the entire process, from the workshops to the property surveys. The company has conducted several other area reassessments, including the recent contentious one in Rotterdam. Niskayuna officials have noted the town’s valuation has fallen to 60 percent.

The final assessment role is to be filed in July, hitting school taxes in September and town and county taxes in January 2009.

Town officials have said they were trying to avoid many challenges by double checking information with homeowners. Surveys were sent out last fall.

Information books have also been placed at the library and special information centers at the Trinity Baptist Church, 2635 Balltown Road. The centers are to be open today from 9 a.m. to 1 p.m., Tuesday from 9 a.m. to 4 p.m., Thursday from 2 to 7 p.m. and Saturday, March 15, from 9 a.m. to 1 p.m.

Much of that information, including information on other assessments is expected to be online at the Niskayuna Web site, Niskayuna.org, starting Monday, Supervisor Joe Landry said.

That was a question Leonard Berger had Friday. He had just been to the library and reported several residents there going through the books, causing wait times.

He said he expects to challenge his assessment. His current estimates have him paying about $380 more per year.

A resident of Niskayuna for some time, Berger recalled a previous reassessment included information on how the assessors reached their numbers, like comparable homes. This time, he said, he has to seek that information out.

“There’s no way of knowing how they got that number,” he said. “It could be a fair assessment, but you don’t know.”

And town officials are trying to answer those questions. The assessor’s office has details on informational sessions.

Landry noted the process is a redistribution of taxes. Some property owners are seeing increases, while others are seeing decreases.

“For every dollar that goes up, another dollar goes down,” he said. “The town is not realizing any net gain.”