What do you call unclean water that you can't see through? Probably contaminated with dirt, prolonged stagnation or mineral erosion, almost pale brown, like stagnated water on a rainy day.
Murky comes to mind.
(of liquid) dark and dirty; not clear.
Oxford learners dictionary
Also consider Stagnant:
having no current or flow and often having an unpleasant smell as a consequence.
I expected Turbid to mean that the water has been stirred to produce the suspension of particles, but if the particles are small enough I would think it works.
Water is said to be turbid when particles suspended in it restrict the transmission of light and give a cloudy or muddy appearance. Only small particles can remain suspended for significant periods of time. Relatively large and dense particles such as sand grains will sink rapidly.
EEA via dpi.vic.gov.au
You can call it opaque; not able to be seen through; not transparent. You might call it cloudy (of a liquid); not transparent or clear. Nonpotable, un-fit for drinking.
Other synonyms include turbid, murky, unclear, muddy, thick and milky. You might also use the Shakespearean hellbroth (uncommon, but from Macbeth).
This question reminds me of the Indus River dolphin, actually evolved a kind of blindness over years due to the turbidity of the water. So the words used in these scientific articles are usually turbid, murky, and they also throw in silt-laden.
The Indus River dolphin is functionally blind having evolved without a crystalline lens or well-developed light-sensitive organ. A deep fold just above the dolphin's mouth is the remnant of what might once have been eyes down the evolution line. However, this is not a disadvantage but an adaptation to living in the silt-laden turbid waters of the Indus where eyes are virtually useless, as very little light penetrates below the surface of the murky water.
Water that is unclean, and no longer transparent is often called murky but there is another adjective, very common and indisputable in its meaning that is used to describe the same phenomenon. Filthy water means water that is dirty, unclean, unsafe, and impure to drink from.
There is a TED talk which describes a filter which makes filthy water safe to drink. The title of the talk is: How to make filthy water drinkable
Okay, so I'm going to take this really filthy water, and put it in here. Do you want a drink yet?
you can use misty water for that!!
mist•y (ˈmɪs ti)
adj. mist•i•er, mist•i•est.
covered or obscured by mist.
consisting of or resembling mist.
indistinct or blurred.
Reference : Misty