Two questions. First, whenever I run a gas line to a major appliance such as a furnace or water heater I always install a drip leg for the obvious reasons. I’ve never thought about it until recently but I have never seen (or at least remember) a drip leg installed on the gas line that supplies the stove/range. Should there be? Am I missing something? :confused:

Second, on some of the new bigger houses (4,000 sq. ft. +, 2+ stories) in the Chicago area I noticed that several of the PVC pipes exiting the roof have what appears to resemble air admittance valves attached. Is this some type of new venting system?

Hi Shader,
As a rule a "drip leg" is installed directly downstream from the gas meter and services the entire house. I think what you observe on the roof vents are back draft preventers to eliminate bad odors from blowing back into the system. We moved out of the Chicago area, (Rockford) over 50 years ago to Florida. Never regretted it. Regards, Tom