Apfel is a masculine noun that uses "der" when it is the subject of a sentence (nominative case). When masculine nouns become the direct object, der become den (accusative case). Nasser is a neutral noun that uses das as the object. Das remains das in the accusative case.
Der becomes den Das stays das Die stays die
For the genitive case (usually caused by the inclusion of certain prepositions...I don't think this exists in English?) der becomes dem, das becomes also dem (not confusing at all), and die become der (totally not confusing at all, haha!)
If the article is in the original German sentence, then you should include it in the English translation, unless it is standard for English to never use it. In this case, I drink the water is an acceptable English sentence. If the sentence was Ich trinke Wasser, then your suggestion would be acceptable.