I have a shower drain that has been leaking. The shower and bathroom was remodeled about 5 years ago. I was expecting the leak to be where the new drain line was tied into the existing drain line. But I have discovered that the leak is coming from where the new vent line was tied into the existing vent. This is at a point about 1 1/2 feet from the floor up the wall. This means the water draining from the shower is backing up into the vent above this point. Should this happen? Is it a problem if I simply fix the leak? BTW, the shower drains at a normal rate.
