Yes, but it could also be from another source. First of all, determine if the source is on your property. Going upwind from your house can help determine this. If the source of the odor is on your property, check for possible propane or gas leaks and take appropriate safety measures if such a leak is the cause. Once you eliminate the possibility of a propane or gas leak, you can move on to the septic system as a potential source. Have the tank pumped if you notice sewage in the yard or it has been 3 to 5 years since you’ve had it pumped out. You could also try having your vent pipe on top of your house extended. If you still have an odor problem, you can try adding bacteria to the tank or call a plumber to check your lines for plugs, breakage or leaks.