"You drink tea."
茶 refers to "tea", whereas 茶水 refers to "tea" (liquid). They both have the same meaning. However, 茶 is commonly used since it's short-formed term.
茶水 cháshuǐ = tea prepared with boiled water
茶 chá = tea plant - tea (like above) - tea drink
As you see, the first one has a more specific meaning than the second one, which can be referred to more things. So your solution is correct, too.