Dale see if you agree:
It's water taken directly from the faucet.Can be warm or cold, but usually when people ask for "tap water" they mean "water at room temperature"(tepid). Some people for health or medical reasons can't drink cold water ( taken from the refrigerator or mixed with ice)
There are other ways to say it. I gave 3 examples and I used "can be" as a last option, not because it's usual but I was just trying to be creative and making use of Mari Camargo's words so... Não é certinho mas aceitável.
- Do you prefer cold water?.[Do you prefer...it's not written but It was obviously implicit
that I could choose (ice cold ,cold,tap(room temp)warm...)]
- Can be ... Can be cold, tap or ice-cold water, even warm, I don't care. I just want a glass of water.
Waiter:What would you like to drink?
Guest: What do you have ?
Waiter: We have soda, juices,iced tea... and water.
Guest:Get me some water.
Waiter: Gave the guest a glass of tap water.
Guest:This water is warm.
Waiter: Do you prefer cold water?
Waiter: Got a pitcher of ice water (water mixed with ice) and filled up the glass
Thanks for your explanation.