Which sentence needs a semicolon added to be correct?
a. (5) water is not everywhere it's miles away.
b. (3) if we want to water our yards or wash the dishes, water is there.
c. (2) if we need a cold drink or want to take a shower, water is there.
d. (4) for many parts of the world, however, this is not true.

The correct answer here is A. The sentence that needs a semicolon added to be correct is A. Water is not everywhere; it's miles away. Semicolons are used mainly to link two independent clauses that both communicate the same idea, such as in the above sentence where both parts of the sentence indicate that water is not always readily available but there was previously no linking punctuation or conjunction.

Both "they're" 's are wrong.

Explanation:

The first one should be They're and the second one should be Their