Televised ducts under slab floor. Ducts are concrete ducts possibly Transite with metal fittings and connections that are very rusted. Plenum off of furnace is at a lower level than the ducts and it extends out away from the furnace. There is standing water in the plenum at this time. If ducts were to be repaired a sump pt and pump would need to be installed and the basement floor broken up to expose the plenum and replace it and also allow access for spin cast mortaring.