There are some differences between the 2006 IRC Plumbing Section and the 2007 California Plumbing Code, which is based on the 2006 Uniform Plumbing Code. Sample: Water Heater’s PTRV; CPC 508.5 - Discharge from a relief valve into a water heater pan shall be prohibited. Think that’s a good rule and would like to see the IRC so adopt. On the other hand, I think Jerry P enumerated them; the IRC has a 13 item list on PTRV piping that CA should adopt. My question; will I live long enough to see one national code?
