Ace Pelizon Plumbing was called out on a stoppage effecting lowest bathroom. Ace Pelizon Plumbing found lowest bathroom tub and toilet holding sewage. ***this home most likely has a backwater valve*** Tech vacuumed out sewage from tub and toilet to allow for pull and reset of this fixture. Removed toilet and ran 1/2 inch cable through closet opening to get line to clear. Ran multiple passes with water flowing to get sludge to flow from lime. Camera inspected sewer from closet opening and found a cast iron back water valve approximately 10 ft from toilet. Located in laundry room (most likely toilet paper build up in cast iron fitting or flapper stuck in place) *** no warranty against future stoppages*** notified customer on site of issue and explained that excavation and physical repair of fitting in ground is the only way to correct problem. Customer asked for camera inspection of sewer main from from clean out to city connection where he knows there has been a root issue in past.