Cloudy tap water is alarming when you first see it, but the most common cause is air dissolved in the water, which is harmless and clears on its own. Sediment looks similar at first, so a few quick checks will tell you which problem you have.

Run the glass test

Fill a clear glass from the cold tap, set it on the counter, and watch it for a minute or two. Air cloudiness shows tiny bubbles that rise, and the water clears from the bottom up, often within a minute. Sediment or fine particles settle, and the water clears from the top down while a layer of grit or silt collects at the bottom. If the cloudiness is still there after several minutes, or you see particles on the glass or the bottom, treat it as sediment.

Check which taps show it

Run each tap in turn and note where the cloudiness appears. If it shows up at every tap, the cause is likely in the supply or the main system. If only the hot tap is cloudy, look at the water heater side. If only one tap is affected, unscrew that faucet's aerator screen and look for grit or flakes. Clean the screen and check again before you assume the problem comes from the house supply.

Watch the timing

Notice when the cloudiness appears. After a well pump has cycled on, or after work on the street or the water main, the supply can carry sediment that settles out again over several hours. Cloudiness that appears only after heavy water use, then clears, usually points to air or a temporary disturbance. Cloudiness that lasts for days, returns on a regular pattern, or comes with grit points to a source that needs looking into.

Check the filters you already have

If the home has a sediment filter, look at its housing and cartridge. A cartridge that has turned brown or gray or is visibly loaded with particles is doing its job but needs a change. A cartridge that looks clean while the water still runs cloudy may be bypassed, leaking around the housing, or installed in the wrong direction. Note the condition before you change anything, so you can compare it after.

When to bring in outside help

If the glass test shows settling grit, the cloudiness appears at every tap, and no screen or filter explains it, ask your water utility whether it had work or a problem on the day you first noticed. If you have a private well, or the utility cannot explain the cause, have a water professional inspect the supply and the system, and consider a lab test to identify the particles. Keep notes on when you saw it, which taps were affected, and what the glass test showed, because those details shorten the diagnosis.