[ben parrish]

Get the lid off the septic tank and run the snake from that end. Depending on the tank you have, there will be more than one lid; you want the one closest to the house. Chances are good that the clog is near the tank. Will your washing machine drain when the toilets won't flush or is it ran to a separate drain field? Sinks will drain when there is a main line occlusion generally because the volume of water is small.