I’m sorry if this is inappropriate to ask so specifically for San Francisco dwellers, but I couldn’t find the answer this online. Does anyone know if PEX plumbing is allowed for water piping solutions?
Looks like San Francisco uses an amended version of the 2015 Uniform Plumbing Code (UPC). So as long as the PEX conforms to NSF 61 and has the marking "NSF-61" or "NSF pw", it should be allowed. A quick call to the San Francisco building department, should provide a definitive answer.