The metropolitan utilities districts shall maintain free of charge the number of hydrants heretofore established for fire protection in the streets of the municipalities constituting such districts and, in addition thereto, maintain regular fire hydrants on service mains in the streets of the municipalities not now equipped therewith and also upon service mains that may hereafter be installed in such municipalities. The board of directors may adopt such rules for the placement and maintenance of such hydrants as long as such rules do not violate any rules and regulations adopted and promulgated by the Department of Health and Human Services. Intermediate hydrants or fire hydrants placed between regular hydrants shall be installed by the district at such points as may be designated and ordered by any one of the municipalities. One-half of the cost of such intermediate hydrants, connections, and installation shall be borne by the municipality ordering the same. The district shall also lower water mains and reset hydrants at their original locations whenever necessary.