A hot tap can pour a glass that looks almost like watered-down milk, then turn clear before you have time to worry about it. That quick change is useful evidence. It helps separate suspended air from material that stays in the water.
Do not judge safety by appearance alone
Clear water is not proof that water is free of contaminants, and cloudy water is not automatically unsafe. Follow any boil-water or do-not-drink notice from your water provider. Stop using the water for drinking or cooking and contact the provider or a qualified professional if it has an unusual color, chemical or sewage odor, oily film, or visible debris, or if someone becomes ill.
Run the two-minute glass test
Use a clean, clear glass. Fill it from the hot tap while the water looks cloudy, set it on a bright counter, and watch it for two minutes. Do not hold very hot water against your skin.
- It clears from the bottom upward: tiny air bubbles are rising and escaping at the surface. The U.S. Geological Survey describes this as the usual cause of milky-looking water that clears after standing.
- Particles sink or collect at the bottom: you are seeing suspended material rather than air alone. Save a photo and compare other taps before deciding where it came from.
- The color or haze stays evenly suspended: do not assume it is a water-heater issue. Compare hot and cold water and contact the water provider if both sides are affected.
- An oily film remains on top: stop using the water for drinking and cooking until the water provider or a qualified professional advises you.
Air-related cloudiness may be more noticeable during cold weather. Seattle Public Utilities notes that cold winter water can hold more dissolved air. Pressure changes and recent plumbing or utility work can also introduce air into the system.
Compare hot and cold water at more than one tap
The glass test tells you what the cloudiness does. A quick fixture comparison tells you which part of the plumbing deserves attention.
When the water heater belongs on the list
If cold water stays clear but hot water at several fixtures does not, collect a few more clues. Persistent grit, flakes, rusty color, a metallic smell, popping or rumbling from a tank, reduced hot-water volume, or a recent repair can point toward the hot-water system. Utah's mineral-rich water can leave scale, but a photo or glass test cannot identify the material or prove that the tank needs flushing.
Do not drain an older tank just to investigate cloudy water. Sediment can obstruct a drain valve, and a valve that has not moved in years may not reseal. Follow the manufacturer's maintenance instructions for the exact model or ask a qualified plumber to inspect it. The Utah hard-water and sediment guide explains what flushing can and cannot fix.
Recent work changes the story
Write down whether the cloudiness started after a water-main repair, shutoff, heater replacement, expansion-tank work, filter change, or plumbing repair. Trapped air after service may clear with normal use, but persistent debris, leaking fittings, pressure symptoms, or a continuing change in water quality should be reported.
After a new water heater installation, compare the model and installation records with the new-heater closeout checklist. Send the installer a photo of the glass and explain whether the hot side alone is affected.
Cloudy is different from rusty, brown, or smelly
White cloudiness that disappears is a different symptom from yellow, orange, red, or brown water. Lasting color can come from the supply, plumbing corrosion, disturbed sediment, or the water heater. Use the discolored hot-water guide to compare those patterns.
A rotten-egg odor also needs its own check because a water-system sulfur smell and a fuel-gas leak are not the same problem. If the odor resembles fuel gas, leave the area and call the gas utility or emergency services from a safe location. For odor limited to the water, use the hot-water odor guide.
What to report
A useful service request includes the city, whether hot or cold water is affected, how many fixtures show the change, and what the glass does after two minutes. Add the heater type, approximate age, recent plumbing work, water-provider notices, noises, odors, color, particles, leaks, and temperature changes.
In Salt Lake City, Sandy, Draper, West Jordan, South Jordan, Murray, Provo, Orem, Lehi, or American Fork, start with the utility shown on the water bill if both hot and cold water changed. If the change is limited to hot water across the home, send those observations with a request for Utah water heater help.
Sources and further reading
- U.S. Geological Survey: Why is my drinking water cloudy? - an explanation of pressure and tiny air bubbles, including why a glass clears as bubbles rise.
- Seattle Public Utilities: Cloudy water - seasonal dissolved-air context and the clear-glass check.
- EPA: Basic information about lead in drinking water - why appearance, taste, and smell cannot identify lead and why testing is the way to know.
Cloudiness limited to the hot side?
Send the glass-test result, heater age and type, city, affected fixtures, and any color, odor, noise, leak, or recent plumbing work.
Request Utah water heater help