A sewage backflow assembly of sewage stopper systems is a check valve designed to operate with low flows such as is found in sewage drain pipes. The check valve disc is light weight plastic and easily lifts when outgoing flow is present but closes when backflow occurs to prevent flooding of building structures. The device has an inlet pipe segment, a flapper housing with a flapper, and an outlet pipe segment. The sewage backflow assembly may be glued into a pipe using glue type slip couplers or may be installed using re-useable pipe clamps.