Learn Hardcore Russian: Необходимо пить воду каждый день. - It is necessary to drink water every day.

“Воду” is the direct object of the verb пить (“to drink”). In Russian, direct objects go into the accusative case. The noun вода (water) is feminine, and its accusative singular form is воду.

What part of speech is “Необходимо” and why is it used here?

“Необходимо” is a short-form neuter adjective (often called an impersonal predicate). It functions like “it is necessary” in English. Because there is no explicit subject, the sentence is impersonal: “It is necessary to drink water every day.”

Why do we use the imperfective infinitive “пить” instead of a perfective form?

The imperfective infinitive пить describes a habitual or repeated action (“drinking water daily”). A perfective form like выпить would emphasize the completion of a single event (“to drink up / finish drinking once”), which doesn’t fit a routine/general recommendation.

Could we replace “Необходимо” with “Нужно”?

Yes. Нужно is less formal but equivalent in meaning. So you could say Нужно пить воду каждый день with no change in the overall meaning.

Why is there no explicit subject like “you” or “we”?

This is an impersonal construction. Russian often drops the subject when using words like необходимо, нужно, можно, нельзя (“necessary,” “need,” “allowed,” “not allowed”). The person obliged is understood implicitly (“one” or “you” in general).

What does “каждый день” mean, and why is it at the end of the sentence?

Каждый день means “every day.” In Russian, adverbial time phrases can appear at the beginning or end for emphasis or style. Placing it at the end focuses first on the necessity, then on the frequency.

Why isn’t there a preposition before “каждый день”?

Expressions of repeated time (like “every day,” “sometimes,” “twice a week”) typically take the accusative case without a preposition. Here день becomes день (no change) because каждый already marks it as accusative.