RO/DI water connection question

[sphelps]

Under your sink you should have some kind of shut off valve for hot and cold so your faucet can be changed without shutting off the building water. After the cold valve you need to install some kind of tee to feed the RO unit. Or you can install a needle pinch valve on a cooper line if you have one exposed, these are usually included with RO units but the tee is the better way to go.