In addition to the requirements of storm sewers for street drainage, storm sewers shall be extended so as to provide each subdivision lot with a direct connection to such sewers for the purpose of directly receiving the discharge of sump pump water from any dwelling or other building which may be constructed on the lot. The direct connection of building downspouts to such storm sewer connections is prohibited unless such connection is shown to be necessary for the public safety and is approved in advance in writing by the City Manager. House leads shall be installed to the front lot line on each lot prior to acceptance of the subdivision storm sewerage system.