White or milky tap water is often trapped air in tiny bubbles, especially after pressure changes. A clear glass can confirm it: if the water clears from the bottom upward within a short time, air is escaping; if particles remain or the appearance does not change, another cause needs investigation.
Use the clear-glass test
Fill a glass with cold water and let it stand. Microbubbles rise and disappear, so the water becomes clear starting at the bottom.
Pressure changes can increase dissolved air
Utility work, household plumbing repairs, or cold temperatures can change how much air remains dissolved. If the water clears quickly and nothing else changed, the cause is usually physical rather than sediment.
Hot-only cloudiness can involve the water heater
Hot water releases dissolved gases more readily. If cloudiness appears only on the hot side and comes with noise or sediment, use that pattern to guide water-heater service without opening pressurized equipment.
Particles that remain are not microbubbles
If the glass remains cloudy, leaves sediment, or changes color, compare other faucets and check supply notices. A household filter should not be treated as a guarantee against an unknown water-quality change.
Sources
- U.S. Environmental Protection Agency (EPA) — WaterSense Home Maintenance — Household water maintenance, leaks, fixtures, and efficiency.