Final answer:
To prevent backflow of contaminated water, an air gap should be installed between the faucet and the flood rim of the sink.
Step-by-step explanation:
In order to prevent backflow of contaminated water, a device called an air gap should be installed between the faucet and the flood rim of the sink.
The air gap is a physical separation that allows a gap of air between the water outlet and the flood rim. This prevents any contaminated water, such as from a clogged drain, from flowing back into the water supply.