Whenever the formation of a district is desired, a petition may be presented at a regular meeting of the board of supervisors of each county in which is located any portion of land within the proposed district. The petition may consist of any number of instruments and shall be signed by not less than five per cent of the registered voters residing within the district, who voted at the last preceding general election at which a Governor was elected. The original petition need not be filed with the board of supervisors of each county, but a certified copy of the original shall be filed.