Water is a mass noun, generally used for things indivisible or uncountable. In English, you can tell if a noun is a mass noun if it cannot be used with the indefinite article "a".
"*Oh hey look, I found a sand"
"Oh hey look, I found a blockchain"
It doesn't fail the test, so it must be a count noun.
(PS: water is a bad example, because "a water" is a common abbreviation for "a glass of water" that's old enough it's probably lexicalized in a lot of people's heads. "sand", "salt", "bread", "wood", or "rice" are better examples)
"*Oh hey look, I found a sand"
"Oh hey look, I found a blockchain"
It doesn't fail the test, so it must be a count noun.
(PS: water is a bad example, because "a water" is a common abbreviation for "a glass of water" that's old enough it's probably lexicalized in a lot of people's heads. "sand", "salt", "bread", "wood", or "rice" are better examples)