 because , while storm drains are designed to accept surface runoff from streets, combined sewers were designed to also accept sewage flows from buildings with basements  .
<clarity>  because , while storm drains are designed to accept surface runoff from streets, combined sewers were designed to also accept sewage flows from buildings with basements  .
 because , while storm drains are designed to accept surface runoff from streets, combined sewers were designed to accept sewage flows from buildings with basements .