The Gwinnett County tax assessor has the duty of assessing properties and issuing tax assessment notices, among others. Taxpayers, on the other hand, have the duty to know the process applied by the tax assessor’s staff in these two aspects for their own benefit. Keep in mind that tax assessments can be appealed (i.e., reduced in value) but tax bills cannot be appealed, thus, emphasizing the importance of appealing your tax assessment within 45 days after its receipt.