We are DIY remodeling a 100 year-old house in OH. We replaced much of the existing plumbing (over 70%) with new PVC to match the new layout. The glue and primer recommended for PVC were used. All lines were "water tested" with no leaks. Inspector requires a pressure test of drain & vent lines. Requirements are that we hold 5 PSI for 10 minutes. We can only hold it for 2 minutes and failed first inspection. All walls & ceilings with plumbing lines are open (no drywall or plaster). All lines are accessible. When we found leaks in old lines, we replaced them with new PVC, so that almost every line is new PVC. After 2 days of searching, our problem is that we cannot locate all leak(s). We need suggestions for finding leaky fittings, small holes etc. Any Pros out there with 'tricks of the trade' that you care to share?