Why Does My Hot Water Look Cloudy or Milky?

You turn on a hot-water faucet, fill a glass, and the water looks white, cloudy, or almost milky.

It can be concerning, especially when the cold water looks completely clear. But in many cases, cloudy hot water is simply caused by tiny air bubbles, not sediment or a failing water heater.

There’s an easy test you can do at home to help tell the difference.

The Clear-Glass Test for Cloudy Hot Water

Fill a clear glass with the cloudy water and place it on the counter. Watch it for a few minutes.

If the water begins clearing at the bottom and gradually becomes clear toward the top, the cloudiness is most likely caused by tiny air bubbles escaping from the water.

As the bubbles rise and leave the glass, the water returns to its normal clear appearance. When that happens, the water usually isn’t dirty, and the appearance doesn’t normally indicate that the water heater is failing.

Why Does Hot Water Sometimes Look Cloudier Than Cold Water?

Water naturally contains dissolved air. Changes in temperature and pressure can cause that air to come out of the water in the form of tiny bubbles. Those bubbles scatter light and give the water a white or milky appearance.

Because the water has been heated and moved through the hot-water system, you may notice the effect on the hot side even when the cold water appears clear. The cloudiness may also become more noticeable after:

• Plumbing work

• Water-main repairs

• A temporary interruption in the water supply

• Changes in municipal water pressure

• Work on a well or pressure tank

• A water-heater installation

• Water being shut off and restored

Air introduced during plumbing work may take a little time to work its way out of the system.

Is the Water Heater Causing the Cloudiness?

The water heater may make dissolved air more noticeable, but cloudy water caused by air doesn’t necessarily mean there is anything wrong with the unit. The first step is determining where the cloudiness occurs.

Cloudiness at Every Hot-Water Fixture

If the hot water looks cloudy throughout the house but clears in a glass, dissolved air is the most likely explanation.

Cloudiness on Both Hot and Cold Sides

If both hot and cold water are affected, the cause may be related to the incoming water supply rather than the water heater. Check with your municipal water provider to see whether recent work has been performed in the area. If your home is on a well, changes in the well or pressure system may need to be investigated.

Cloudiness at Only One Fixture

If the problem occurs at one faucet, remove and inspect the aerator. An aerator intentionally mixes air into the water stream. Debris or an irregular flow through the aerator can make the water appear more cloudy at that fixture than elsewhere in the house.

What if the Cloudiness Doesn’t Clear?

Water that remains cloudy after sitting in a glass may contain suspended material rather than air. Look closely at what happens:

• Does material settle at the bottom?

• Are particles floating in the water?

• Is the water gray, brown, yellow, reddish, or black?

• Does it leave a residue?

• Is there an oily film?

• Does it have an unusual odor or taste?

Persistent cloudiness or visible particles may be related to:

• Sediment in the water supply

• Corrosion in older piping

• Recent water-main work

• A well-water issue

• Deteriorating plumbing components

• Debris introduced during plumbing repairs

• A water-filtration problem

Don’t assume that every cloudy-water problem is coming from the water heater. Comparing several fixtures and comparing the hot and cold sides can help narrow down the source.

What if the Hot Water Is Discolored?

White or milky water that clears is different from rusty, brown, yellow, green, or black water.

Discolored hot water could involve the water heater, piping, water source, or another component in the plumbing system. For example:

• Reddish or brown particles may indicate rust or iron

• Black particles can sometimes come from deteriorating rubber components

• Blue-green staining may be associated with copper corrosion

• Sand or grit may come from the water supply or a well

• An oily appearance needs further investigation

If the water is visibly discolored, contains particles, or smells unusual, avoid assuming that it’s harmless air. The source should be identified.

Could High Water Pressure Contribute?

Pressure changes can cause dissolved air to become more visible when water leaves the faucet. If the home also has unusually strong pressure, leaking fixtures, frequent supply-line failures, or a pressure-reducing valve that isn’t working properly, the plumbing pressure should be tested.

High water pressure can affect much more than the appearance of the water. It can place additional stress on the water heater, expansion tank, fixtures, and appliance connections.

When Should You Call a Plumber?

Call a plumber when:

• Cloudiness doesn’t clear after sitting

• You see sediment or particles

• Only the hot water is discolored

• The water has an unusual odor

• The problem started after water-heater or plumbing work

• Water pressure has changed

• The water heater is leaking or making unusual noises

• You aren’t sure whether the water is safe to use

If the problem affects both the hot and cold water throughout the house, contacting the municipal water provider may be the best first step. Homes on private wells may need water testing or well-system evaluation.

Not Every Unusual Appearance Means the Water Heater Is Failing

If cloudy hot water clears from the bottom of a glass upward, you are most likely seeing tiny air bubbles. If it doesn’t clear, contains particles, has an unusual color, or appears only on the hot side, the plumbing system may need to be inspected.

Hot Water Solutions provides water-heater repair, replacement, water-filtration, and general plumbing service throughout Kennesaw and surrounding Metro Atlanta communities. Call 678-540-6164 if you’re concerned about the appearance of your hot water or the operation of your water heater.

Because a cold shower should be by choice.

Related Reading

• Why Does My Water Heater Smell Like Rotten Eggs?

• Why Is My Water Heater Not Getting Hot Enough?

  
  

FAQ Questions for Rich Results

Why does my hot water look cloudy but then turn clear?

The cloudy appearance is usually caused by tiny air bubbles. If the water clears from the bottom of the glass upward, dissolved air is the likely cause.

Why is only my hot water cloudy?

Heating and pressure changes can cause dissolved air to form visible bubbles. If the water clears after sitting, it usually doesn’t indicate a failing water heater.

Why is the water cloudy at only one faucet?

The faucet aerator may be mixing additional air into the water or may contain debris. Compare that fixture with other hot-water faucets in the home.

When should I be concerned about cloudy water?

Have it investigated if it doesn’t clear, contains particles, has an unusual color or odor, leaves a residue, or appears alongside other plumbing problems.