What's the difference between" 冰水“ and " 冷水“？

冰水iced water(with ice or freezingly cold water)，冷水cold water

冰水 is water that is from ice melting or be very frost in the refrigerator.冷水 just mean that the water is cold.

冰 is colder than 冷，that is the difference. 冰>冷。

如果是在餐厅大部分情况下是使用冰水

冰水 iced-water；冷水 cold water。

冰水ice-water

 冷水unboiled water or cold water

iced water and cold water

给我一杯冰水（for drink）

洗冷水澡（for shower）

As you can see the meaning of 冰水 is iced-water, however 冷水 has the meaning unboiled water to compare their difference meaning.

冰水：the temperature of water is zero or below

冷水：commonly cold water