Abstract: The invention is a bi-directional cleanout for pipelines such as sewer pipelines and a bi-directional cleanout with a built in backflow preventer. The backflow preventer is a check valve which allows fluid to flow in one direction, but not in the other direction. The bi-directional cleanout is a device which has a single access point at ground level, is located outside a house typically, and which directs a cleanout tool down one of two tool guide tubes. The guide tubes direct the cleanout tool into one of two tool guides which deflect the cleanout tool and cause it to enter the pipeline to be cleaned in a direction towards one or the other of the ends. The check valve is insertable into the pipe level unit in which the tool guides are located. While the pipeline is being cleaned out with the cleanout tool, the check valve can be removed and reinserted after the cleanout procedure is completed.