I HAVE A SEPTIC TANK THAT IS 4 YEARS OLD.FOR THE LAST 6 MONTHS THE BATHTUB ON THE UPPER FLOOR WILL START TO DRAIN AND CAUSE BOTH TOILETS UPSTAIRS TO BUBBLE AND SPLASH WATER, THEN THE TUB STOPS DRAINING, FOR 5 MINUTES THEN TAKES OFF DRAINING WITH SUCH FORCE IT SUCKS THE WATER OUT OF THE TOILET’S, NO PROBLEMS IN LOWER BATHROOM, NOW MY WIFE IS GETTING MUD OUT OF THE DISHWASHING MACHINE DRAIN!! HELP!!
This will require a video inspection of your main line sewer to diagnose properly. Number one the upstairs sewer is not venting properly, Number two the downstairs dishwasher is directly related to your upstairs problem. A video inspection of the sewer from the house to the tank should be very enlightening. Good Luck, Bill The Local Plumber Tustin, California http://www.TheLocalPlumber.com