In each city owning a system of waterworks there shall be a department to be known as “waterworks department” of such city. The board of commissioners shall maintain, manage, conduct and control said waterworks, and make all such ordinances, rules and regulations as are necessary for the safe, economical and efficient management of the waterworks. Said board may also improve and extend the waterworks, furnish supplies of water to the inhabitants of such city and for fire protection, collect water rents, and appoint all necessary officers and agents for that purpose.