The city side of the main vent trap had a clog, contributing to the backup was the washer and bathtub draining simultaneously... if one or the other had been draining separately the clog might not have been discovered until things got worse.
City came and flushed the system, drained the bathtub 3 times... no problem.
Now the missus has her shower back, her laundry room back and i have my peace and my piece back
