A. An auxiliary water supply which is or can be connected to any potable water piping is available; or

B. There is piping for conveying liquids or gases other than potable water which is under pressure and is installed or operated in a manner which could cause a cross connection; or

C. There is intricate plumbing which makes it impractical to determine if a cross connection exists; or a domestic service exists; or

D. There is a fire service or irrigation service or a domestic service two inches or larger in size. Devices shall be required on all domestic services smaller than two inches if the building is more than two stories or higher than thirty-two feet above the water main.

E. There are irrigation service bibs similar to those used for potable water.