An air gap separates the water supply from the hazard and is considered the highest level of protection.
Reduced pressure zone assembly is high level of protection.
This "N" type RPZ saves space on the installation.
Backflow preventers come in sizes from 1/2 inch to 12 inches and more.
This double check valve protects against low level hazards.
An example of DCVA in red and RPZA in blue installed outside of a warehouse.
Pressure vacuum breakers may be used on irrigation lines where freezing isn't a problem.
A properly installed pressure vacuum breaker.
Atmospheric vacuum breakers protect from back-siphonage only. There are special rules for use.
This AVB is used indoors, such as above a mop sink or a bed pan washer.
A hose bib is used on faucets to prevent back-siphonage through a hose.
A sillcock without and with a hose bib.