Failed the DWV rough because we tested with air and the inspector wanted water?

Asked by benplumb79 · Jul 26

Sorry if this is a basic one. We failed a plumbing rough today on a basement bathroom in Hillsborough. We had the DWV on air, gauge was holding, and the inspector said he wanted a water test and wouldn't look at it. My boss was annoyed but said this town has always been like that, and the next town over takes air with no problem. Is that a code thing or an inspector thing? I'd like to understand it before the retest Thursday instead of just doing what I'm told. edit: filled the stack, passed Thursday. Still curious about the why if anyone knows.