All water has been filtered.
All water have been filtered.
I’ve already searched about this especially in youtube. From what I learned, if it’s an uncountable noun after determiner all, it will be treated as singular therefore has should be used.
I just need a confirmation that’s why I posted a question here.
Uncountable nouns are treated as singular:
All water is wet.
All the sand has been delivered for the playground.
All life is precious.
Source : Link , Question Author : Karlo Kokkak , Answer Author : The Photon