No individual shall be eligible to apply for examination unless the individual is at least 18 years of age at the date of application. The board of commissioners may accept applications from nonresidents of the township and may require nonresident police officers and nonresident paid firefighters to become residents of the township after appointment to the positions. The rules and regulations of the civil service commission shall reflect the residency requirements of the board of commissioners or a collective bargaining agreement or award.
53 P.S. § 55639