I presume, from the fact that you are asking this question, that you are not familiar with the standard EU procedure for taking duty-free liquids through security.

At EU airports any liquids bought at other EU airports or on board EU-operated aircraft may be taken through security if they are sealed inside an approved clear bag at the point of sale, with a receipt inside the bag showing where and when they were purchased. (The receipt is only valid for a limited period - I think it's 24 hours)

Schiphol (and other airports where security is at the gate) have always treated water the same as other liquids. Schiphol still lets you take alcohol and perfumes etc through security but not water. Insane.