The sprinkling in districts so established may be done by contract or by forces employed by the city, or by both, in such manner as the council may elect. It shall be the duty of the council to estimate, as near as practicable, the cost of sprinkling in such districts so established for the season, and before the first Monday in November in each year, they shall pass and finally adopt a resolution levying and assessing all the property within the several districts with an amount equal to not less than seventy five percent (75%) of the entire cost of the work, exclusive of the cost of sprinkling parks and public places. (1975 Code § 12.24.040)