Linguistic approach to the term "water".
The term Water is a noun of feminine gender, whose first letter is a a tonic.
For these nouns and for those that start with he has, for phonetic reasons, at some point the rule was created to change the feminine definite article, the, for the masculine, he: Water.
This rule only applies when the definite article immediately precedes the noun. If another word is interposed, such as an adjective, the article must be in feminine: the same water.
Since the term Water is a feminine noun, if it is followed by an adjective, it must also end in feminine: pure water.
The feminine indefinite article, a, is usually changed by the masculine, a, as long as no other word intervenes: a pure water.
However, if another word is interposed, such as un adjective, then the indefinite article is feminine: a refreshing pure water.
The plural is preceded by articles in feminine, the waters, some waters.
In the case of adjectives some and none, can keep full or full form some water, or take the apocopated form, no water.
Regarding demonstrative adjectives this, that, that, or determinative adjectives, like everything, a lot of, little, nothing, other, the feminine forms should be used: this water, much water, another water.
In the case of derivatives of feminine nouns that begin with a tonic, when they stop carrying the accent on the a initial, must be preceded by the articles, both determined and indeterminate, in feminine: the little waters, some water.
The same in the case of compound feminine nouns, whose first element, as an independent word, begins with a tonic. The correct is aquamarine.
Remember that the above rules apply to any feminine noun that begins with a or by he has tonic: alga, area, bird, anchor, ax, aura, mistress, soul, act, wing ...
The area of this land, a very sharp ax, the responsibility of the housewife, ...
The rule of changing the feminine definite or indeterminate article for masculine does not apply to some nouns such as: the letters of the alphabet, the H, and proper names of women, the amelia.
Regarding female toponymics that begin with a tonic, the application of the rule has exceptions. For example, in the case of continent names, the correct thing to do is africa and Latin America. In the case of cities or countries, the form is preferably used the, which is even part of the proper noun, as in the case of Hague. Another would be the Amsterdam of my memories.
On the other hand, these rules do not apply to adjectives, adverbs or prepositions. Therefore, the following expressions are correct: the sour situation, the still single, the former student, the boss until yesterday.
It is common for people with high academic training to use the definite and indeterminate articles correctly in the case of feminine nouns that begin with a or he has tonic, and that they construct the rest of the sentence as if they were masculine:
. This water is one of the purest ...
. ANDhe water in this region of the country is highly polluted.
. ANDl ax must be sharp.
Finally, a particular case is that of the noun art, which is masculine in the singular, and feminine in the plural. It is right roman art, refined art (an exception is poetic art), and it's correct, too, performing Arts or the plastic arts.