Problem originated a week ago after downstairs toilet was pouring water out of base anytime we used water anywhere in house. Plumber snaked line and found nothing. Replaced wax ring. Next we had our septic system pumped. We were OK for a couple of days. Last night when washing machine was draining, the downstairs shower backed up and flooded the bathroom? Was it just to large amount of water dishcharge. Again the shower backed up fast and flooded the bathroom floor. Is downstairs shower line clogged? It drains fine when you take a shower? Any advice is appreciated

UPDATE! I believe I resolved the problem. Not sure how but the outlet where the septic pump was plugged in tripped. I had to reset it now it's on. We'll see if that fixes it... :)