比较严肃正式的文体一般选择1，不太正式的文体选择2，就近原则。非母语的初学英语的人可能会选择3. 3应该属于错误用法。

我给你提供几个外刊例句供参考：

1. They should use it to visually estimate how much water and other liquids they drink when they don't know for sure.

2. How does a physician know how much water and electrolytes, particularly sodium and potassium, to give to a child? 

3. How could we enter a contract that says we want to buy water, and that we, from our side, didn't give direction to the contractor as to how much water and how many units it had to go to?