For the past week we have had the smell of sewer in our house. It comes and goes. Someone got up on our roof and cleared the vent of ice and snow and it seemed to go away. The next day it was back. Now its back really BAD! I don't know know what it could be.

Still sound like venting. Smell all of the sinks/tub/ basement and see where the smell is strongest. Did anyone knock some ice and snow down the vent and it closed that way even though you thought it was cleared I would pour a good amount of hot water down the vent to eliminate it as a possible and go from there
Hope this helps
Need more info if hot water doesn't work
Signed 21boat

I'd have to agree, it is likely still the vent issue. It is difficult to clear ice from the inside of the stack without some of it falling down inside. A few buckets of hot water should be more than enough.

A couple of suggestions. First of all the nature of sewer (smells) is to settle in the lowest part of the house, in your case the basement. If you have any floor drains, washroom any plumbing dreains at all, they need to have water in them to trap the odors. A floor drain trap will evaporate allowing sewage gases to escape, same as a sink or tub drain. If you have these drains, pour water in them, run the sink, flush the toilet. See if that takes away the odor. And a venting problem will also create a vacumn which would empty these traps.