Nassau County residents can now challenge their property tax assessment online thanks to a new program unveiled by County Executive Tom Suozzi.

The tax assessment service was launched in January and county officials say it has handled about 11,000 cases. Suozzi says it is helpful because the county would rather collect the correct amount than have to pay back homeowners each year.

Nassau Board of Assessor's chairman Harvey Levinson says the free service is easy enough for anyone to use. Homeowners and business owners have until March 1 to file grievances for the next tax year.