Where should the RO faucet be installed during the setup of a reverse osmosis system?

The reverse osmosis (RO) faucet should be installed upstream of the P trap. This is important for several reasons. First, placing the faucet upstream of the P trap ensures that the RO water, which is purified and free from impurities, doesn't mix with wastewater or other contaminants present in the drain line. The P trap is designed to trap debris and prevent sewer gases from entering the home, but it can also harbor bacteria and other unwanted substances. By installing the RO faucet upstream, the integrity of the clean water being dispensed is maintained, minimizing any risk of contamination.

Additionally, installing the faucet at this location facilitates proper drainage and functioning of the reverse osmosis system, allowing for optimal performance and efficiency. This setup is crucial for ensuring clean drinking water. The other options do not provide the same level of protection against potential contamination.