All of the water is polluted.

Each of the wather is polluted.
Some of the milk is bad.
Some of the apples are rotten.
All of the milk is decayed.

(Are all the expressions grammatical? - The subject verb agreement-)

2 answers

1 is fine.
2 is not used.
3 is fine.
4 is fine.
5 is not used.
Your subject/verb agreement is correct for all sentences.

However, we don't use "each" with "water."

We also don't describe "milk" as "decayed." Milk goes sour or spoiled.