Backflow and the subsequent cross connection can happen wherever your nonpotable plumbing system meets the water lines. As such, many different types of fixtures and appliances are at risk, including:
Sprinklers
Washing machines
Kitchen and bathroom faucets
Bathtubs and showers
Toilets
And more
For commercial properties like industrial facilities, equipment such as boilers, chemical mixing tanks and laboratory equipment are vulnerable to backflow, etc.