You can mix protein powder with water in most cases, although some powders don't mix as well as others.
Yes beef protein powder can be mixed with water, but it can be a little harder to get a good clump free result when using a shaker bottle sometimes.
Yes, in most cases plant protein powder can be mixed with water but can sometimes take a little more vigorous shaking to mix.
Rice protein powder can be mixed with any liquid you desire including water, coconut water, juice, milk, almond milk or soy milk.
Yes, protein powder can be mixed with water without great difficulty, but it does taste better with milk.
You can mix pea protein powder with any liquid to suit your taste, including water.
Hemp protein powder does not mix as well as most other protein powders and it tends to take some fairly vigorous shaking to remove clumps.