Why Does My Water Look Milky or White When I Turn On the Tap?
Tap water looks whitish or milky, a bit like it's been mixed with milk. The instinct is often worry, but in the vast majority of cases, the explanation is simple and harmless.
The most common cause: air in the water
Tiny air bubbles dissolved in the water, often caused by pressure changes in the network or by water that's recently passed through plumbing work, temporarily create this milky look. These bubbles rise naturally and the water clears from the bottom of the glass upward within seconds to a minute.
How to confirm it's air
| Test | Result confirming air |
|---|---|
| Fill a glass and watch it without touching it | Water clears from bottom to top within under a minute |
| Compare a glass of hot water vs. cold | Hot water generally holds less dissolved air and looks clearer |
When it's not air
If the water stays cloudy after several minutes without clearing, or has an unusual taste or smell on top of its appearance, the cause could be different — possibly sediment or dissolved minerals at a high concentration, particularly for a property on a well.
Why it happens more often after certain events
Recent plumbing work in the home or municipal network, a sudden change in water temperature, or abnormally high water pressure often introduce more air into the system, explaining why the phenomenon tends to show up right after these specific events rather than continuously.
When to worry more
Water that stays persistently cloudy, never clears in a glass, or comes with a change in taste warrants a water test, particularly to rule out contamination at the source itself rather than a simple dissolved-air phenomenon.
Frequently asked questions
Is milky water safe to drink?+
If it clears within seconds in a glass, yes, it's almost always dissolved air and harmless.
Why does hot water seem less often milky?+
Hot water generally holds less dissolved air than cold water, which is why the phenomenon is more visible on the cold side.
Can this phenomenon damage the plumbing?+
No, dissolved air in water causes no damage to the plumbing and dissipates naturally without any intervention needed.
Should I get my water tested if the phenomenon persists?+
Yes, especially if the water never clears or you're on a well — a test confirms whether something other than dissolved air is at play.
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By Julien Fortin — RBQ-licensed plumber, 10 years of experience in residential plumbing
Updated on July 22, 2026