The 11 Reasons Why is Your Hot Water Cloudy

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Discovering that your hot water is cloudy can be a great cause for concern, especially if you drink water from your faucet.

1. Air bubbles

Cloudy water, sometimes known as milky or white water, typically occurs due to air bubbles getting trapped in the pipes. Cold water has a greater capacity to hold dissolved air than hot water. When cold water in your pipes is circulated through the water heater, it inevitably warms up and subsequently loses the ability to hold the air in a dissolved state, resulting in air bubbles. 

While the water is subjected to high pressure within the pipes, the air is trapped. When you open a faucet in your home, the pressure suddenly drops, which results in the air in the water being released in the form of tiny bubbles. These bubbles are what give your hot water a cloudy or milky appearance.

Another way air bubbles can occur in your water supply is when water-soluble gases such as oxygen,  chlorine, carbon dioxide, and hydrogen sulfide enter the mains supply. Although all main supplies contain a small amount of air, a damaged pipe may introduce more air into the water supply. These gases create air pockets/airlocks in the plumbing system, and as they get carried along in the pipes, they dissolve in the water. When you open your hot water faucet, the pressure is suddenly released, and the water-soluble gases spurt out into tiny air bubbles, giving your water a cloudy appearance.

2. Dirty faucet aerator

Your hot water may be cloudy due to a dirty faucet aerator. A faucet aerator is a mesh cap device installed on the end of your faucet to help prevent splashing from the water flowing into the sink. A lesser-known purpose of this device is to help reduce/prevent water from clouding up from air bubbles. The aerator does this by breaking the stream of water into smaller streams or droplets, creating a larger surface area for the water to dissipate the air bubbles. If your faucet aerator is dirty, it won’t adequately perform this second function, resulting in cloudy, hot water. 

3. Cloudiness may be caused by hard water

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If you live in an area served by a hard water supply, you may experience limescale build-up in your pipes or appliances, which may subsequently cause your water to appear cloudy. 

Hard water contains many dissolved minerals (mainly calcium and magnesium) when hard water is agitated through heating, limescale forms, resulting in chalky deposits inside pipework and taps connected to the boiler or water heater. 

4. The presence of total suspended solids (TSS)

TSS refers to all the particulate matter in water that remains suspended in the water. Some of the solids that may be present in your water supply include:

  • Sediment
  • Silt
  • Clay
  • Algae
  • Manganese 
  • Iron 

These particles can find their way into the water supply when drilling activities are nearby or if flooding occurs in your area. If your hot water is cloudy due to particulate matter, it will not clear quickly, and you may even be able to spot the individual pieces of sediment if they are large enough. 

Most TSS is harmless, with the main problem being that they can cause water to appear dirty. That being said, if you have a private water supply such as a well or borehole, and you use a UV filter to sterilize the water, particulate matter can shield harmful bacteria from UV rays, making you more susceptible to water-borne illnesses.

5. A faulty water heater anode

If hot water from your faucet is excessively cloudy and tends to stay that way without clearing, the issue may stem from your water heater itself. The anode rod (typically factory installed) in your hot water cylinder is there to prevent rust by maintaining an invisible film of free hydrogen on the entire surface of the heater. 

The anode is installed where rust initially forms – in the water tank. It performs the same function as “sacrificial metals,” which draw the metallic ions in the cathodic area and keep them from mixing into the solution, protecting the tank against corrosion. This is most likely to occur in water heaters that are less than a year old, and in most cases, it disappears over time.

6. The presence of methane gas in the water

While methane gas is highly uncommon to find its way into your water supply, it’s not entirely impossible. This issue can occur in areas where water is supplied from wells (private wells or wells that provide water to cities and districts). Methane is a flammable, colorless, odorless, and tasteless gas. Because of these properties cannot be easy to detect (unless the water also contains hydrogen sulfide). Furthermore, methane acts the same way as air bubbles – it also rises to the water surface and escapes.

7. High water pressure

Your hot water may be cloudy due to a change in the water pressure. An increase in the water pressure results in excessive air getting trapped in the pipes. This is likely to happen if:

  • The heater and plumbing system in your home use a well system
  • There is a disturbance in the water supply pipes, such as when a utility company switches from one well source to another. 

When water is compressed in pipes, it forms tiny water bubbles, resulting in a carbonated effect that gives the water a cloudy appearance. Once you open the faucet, the water is no longer under pressure, so the air bubbles are released. As the air bubbles dissipate from the water, it becomes clear. 

8. Cold weather

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Cloudy water also commonly occurs when the weather is cold. You’ll often find the issue happening more in the winter months than in the summer. Cold water can hold more air than warm water, so when the water coming from a cold reservoir to your tap warms up along the way, some of the air is no longer soluble and subsequently gets released from the solution, giving the water coming from the tap a milky appearance. 

9. Use of ozone disinfection

Ozone is often used by some local water authorities to disinfect water. Ozone gas occurs when oxygen molecules collide with oxygen atoms. Ozone is becoming more popular as an alternative to chlorine because it’s more effective at destroying bacteria and viruses.

10. The use of biguanide sanitizer

Biguanide is another non-chlorine treatment that can be used to sanitize water. When used correctly, biguanide doesn’t irritate the eyes and skin, plus it can also help reduce the water’s surface tension, giving it a smoother feel. That being said, it can provide hot water with a cloudy appearance and can also introduce a pungent odor when used over a prolonged period.

11. Repairs by the water department

It’s not uncommon for the water department to shut off the mains to carry out repairs in some areas. During the shutoff, air can get into the water mains and subsequently dissolve in the water. Once the water company turns the mains back on, water pressure goes back to normal. At this point, if you open the tap, the water may have a cloudy appearance.

How to determine whether your hot water is cloudy

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To help you determine if your hot water is cloudy, all you need is a glass, bowl, mason jar, plastic jar, or any other clear/see-through container. Turn on your faucet and run the water into your see-through container to get started. Once it’s filled, set the container on a flat surface and observe. While watching the water, keep the following things in mind:

  • Which direction do the bubbles dissipate from – the bottom up or the top down?
  • How long does it take for the bubbles to dissipate (if at all)?

If the water clears in just a couple of minutes and it clears from the bottom up, you most likely have oxygen bubbles in your water. If it clears from the top down and takes longer to clear, there’s a high chance you may have particulate matter in your water. If your water takes longer than 24 hours to clear, there could be some maintenance on a water main going on or something similar.

Related article: Why Is My Water Pressure Low In My Apartment?

How to fix your cloudy hot water

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1. If caused by air bubbles

Air bubbles in water are completely harmless, so there’s no need to take action. However, if it bothers you, flush the water from the tap for a couple of minutes until it runs clear.

2. If caused by a dirty aerator

If you think the culprit is a dirty aerator, the most effective solution is to take it off and clean it. Here are some guidelines on how to go about it:

  • Remove the aerator

Begin by removing the aerator from your faucet. To do this, turn the bottom of the faucet clockwise. You may successfully remove it with just finger strength, but if it’s too tight, you’ll need to use a wrench.

  • Clean the aerator

After removing the aerator, check both sides to see if there’s any build-up that may be affecting its function. If you spot any gunk, clean it off using an old toothbrush or a washcloth. You can remove debris trapped in the mesh using a needle or toothpick. If the dirt is too difficult to remove, consider soaking the aerator in a cleaning solution overnight to make the cleaning process easier.

  • Replace the aerator

Once the aerator is clean, screw it back onto the faucet by turning it counterclockwise. After replacing the aerator, test the water to see if it’s cleared up. If it’s still cloudy, you may have another problem.

3. If caused by hard water

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While there are no health issues associated with drinking cloudy water caused by hard water, the discoloration (and/or the unpleasant taste) can be unappealing, especially if the chalky deposits build up on taps and other appliances. There are several ways you can remove the minerals that harden the water and cause cloudiness, including polyphosphate scale inhibitors, calcium treatment units, and water softeners.

Related article: 8 Reasons Why Does Your Washing Machine Smell

4. If caused by total suspended solids (TSS)

If you suspect the presence of particulate matter in your water supply is making your hot water cloudy, consider installing a sediment filter. A standard cartridge or bag water filter will be efficient for less severe cloudiness. For more severe cloudiness, a mechanical water filtration system like a water filter housing with a specialist drop-in sediment filter may be more ideal.

5. If caused by a faulty water heater anode

If your water heater is less than one year old, your hot water is more likely to be cloudy. You might want to wait out in such a case as it will disappear over time. On the other hand, when water from all of your hot water faucets turns milky, it could be an indication that your anode needs to be replaced. Fortunately, replacing an old anode rod is relatively easy and affordable.

6. If caused by the presence of methane in water

If you suspect that methane gas is the culprit, make a point of having your water tested by a professional to measure the exact methane gas levels. The solutions will vary depending on the level of methane in your water:

  • Below 7 mg/L – continue routine testing to monitor levels, but no action is necessary.
  • Between 7 mg/L and 28 mg/L – install a vented well cap.
  • Higher than 28 mg/L – install an aerated tap to allow the gas to dissipate faster. The aerator has to be vented to prevent the risk of explosion.

7. If caused by high water pressure

Cloudy, hot water caused by high water pressure can be fixed by purchasing and installing an aerator on the problematic faucet. An aerator will essentially slow down the flow of water coming out of your tap, thereby reducing air bubbles.

8. If caused by cold weather

If your hot water is only cloudy during the winter, there’s no need to look for a solution – the water will clear up on its own in the warmer months.

Related article: Why is My Water off in My Apartment?

Final thoughts

In most cases, cloudy, hot water will clear up on its own. However, if it takes longer than 24 hours for your water to clear up, consider having your water tested to determine the issue.

Zoltan Szatmari

Zoltan is a test and industrial engineer from Europe who loves learning anything new and working on small projects. When he is not working, he is usually hiking or going to the cinema.

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