If a clear glass becomes transparent from the bottom upward within a minute or two, tiny air bubbles are the likely explanation and filtration is unnecessary. Persistent haze, settled particles or sudden discoloration deserves a different diagnosis.
Use a clear glass before doing anything else
Clears from bottom upward
Strong sign of dissolved air.
Particles settle downward
More consistent with sediment, scale or debris.
Haze never clears
Persistent turbidity deserves investigation.
Only hot water is cloudy
Check the heater and hot-water plumbing first.
Why pressurized water can look white or milky
USGS explains that water in plumbing can hold dissolved air under pressure. Once the water leaves the faucet, tiny bubbles form and make the glass look cloudy. The bubbles rise and disappear naturally.
If this is what you are seeing, there is no contaminant for a filter to remove.
Persistent cloudiness is a different problem
Cloudy water that does not clear can come from suspended sediment, utility disturbances, well sediment, oxidized iron or manganese, or plumbing debris. One faucet points toward local plumbing; every faucet points toward the incoming supply or broader household plumbing.
Only treat what remains after diagnosis
Air bubbles: no filter is needed.
Visible sediment: a sediment prefilter may help after the source is identified.
Iron or manganese: oxidation and whole-house media treatment may be more appropriate. See our iron guide and manganese guide.
Unknown persistent issue: test before buying expensive equipment. See our water-testing guide.
Cloudy water questions
Why does cloudy tap water clear after sitting?
Tiny air bubbles rise out of the water after pressure is released at the faucet. USGS notes that this is a common and harmless cause of milky-looking water.
How can I tell air bubbles from sediment?
Fill a clear glass and let it sit. If the water clears from the bottom upward within a minute or two, dissolved air is the likely cause. If particles settle to the bottom or the haze persists, investigate sediment or another source.
Do I need a filter for cloudy water?
Not when the cloudiness is only air. Persistent sediment should be diagnosed first; the appropriate treatment can range from a sediment cartridge to well-system work depending on the source.