I am getting sewer gas in my basement and discovered the vent pipe has frozen over. 2 questions: Can I use hot water to unfreeze it and is there a cap or something to prevent this from happening again.
Depending on the type of material (piping) you have whether you can use hot water to thaw this pipe. Some piping materials like plastic become very brittle in cold weather and throwng in hot water may crack this pipe.
Using a CAP on a vent pipe is the same as having it blocked with the ice
What should be done is increase this vent pipe in size 24″ BELOW the roof level
If your concerned about the vent terminal being blocked with foreign debris like leaves or nests you could opt for a vandal proof top Or look into a return bend to prevent foreign objects from entering this pipe.