Why Is My Reverse Osmosis Water Cloudy? Causes and Solutions

If you’ve been using reverse osmosis (RO) water filter and have noticed your water suddenly becoming cloudy, there are a few things that could be happening like dirt in the filters, mineral deposits buildup, bacterial growth inside storage tanks, or air bubbles in the RO system.

In this article, we’ll explore some of the most common causes of cloudy RO water and what you can do to fix them easily.

How does reverse osmosis work?

Reverse osmosis is a water purification process that uses a semi-permeable membrane to remove impurities from water.

The membrane allows water molecules to pass through while blocking larger molecules, such as salts and pollutants.

How does reverse osmosis work - Process Diagram

To create reverse osmosis water, pressure is applied to the water forcing it through the membrane. This pressure creates a barrier against the natural flow of fluids, which is reversed when the wastewater leaves the system.

In other words, reverse osmosis forces clean water molecules through the membrane while pushing salt and other pollutants back.

Why does my reverse osmosis water looks cloudy? What can I do about it?

If you have recently switched to a water filter that uses RO to purify your water, you may have noticed that the reverse osmosis drinking water clouded up immediately.

This can be due to the high pressure of the RO membrane or the high mineral content in the water.

Reverse osmosis makes water cloudy

The Reverse Osmosis process removes large particles and molecules from the water which can cause a cloudy appearance. It is important to keep in mind that this cloudiness is not harmful and will lessen over time as the smaller particles and molecules are filtered out.

Another reason for the filtered water clouding up is due to particles and molecules that are not removed by the RO membrane. These particles can come from the water source or your pipes. If you have a well, then these black silt particles may be coming from the well water.

The RO membrane removes the larger particles from your water, but it does not eliminate all of them. These particles can build up in your pipes and can cause clouding in water.

Major Factors for the Cloudiness in Water from my Reverse Osmosis System

Some of the factors that may cause water clouding are:

1. Inefficient filtration from the City water supply

Unlike well water, city water is not free from contaminants. The city’s water filtration is not able to clear all of the sediment and dirt from the water, which causes it to be cloudy.

City Water Filtration System

This can be frustrating for residents who are trying to enjoy a clear glass of water or take a shower.

The best way to ensure clean water is to make sure your water is filtered properly. This can be done by using a carbon filter, whole-house water filters, or a reverse osmosis system.

2. RO Membrane becomes Faulty

The water becomes cloudy as the RO membrane gets clogged with sediment. This is a very common problem in reverse osmosis systems. The best way to prevent this is to make sure that your RO system is properly maintained.

RO Membrane is Faulty

Do note that maintaining the RO system is very important for the long life of the RO membrane and for the better taste of the water. However, if the membrane is faulty, it will make the water cloudy and less safe to drink.

Reverse osmosis membranes can be damaged by a variety of factors, including but not limited to:

  • Contaminants in the water source can foul the membrane.
  • High concentrations of total dissolved solids (TDS) in the water can cause scaling or deposition on the membrane surface.
  • Elevated levels of pH can also cause scaling and deposition on the reverse osmosis system’s membrane surface.
  • Excessive amounts of organic material in the water can lead to biofouling and reduced membrane efficiency.

The good news is that it is very easy to fix a reverse osmosis membrane. You can easily clean or replace the membrane in under an hour by referring to the instructions provided by your RO system manufacturer.

3. Bacteria growth in the RO storage tank

Bacteria in RO tank causes cloudy water

The storage tank in an RO system can become cloudy due to the growth of too many organics, such as algae or other bacteria. This can cause the water to become cloudy and/or foul-smelling.

A number of factors contribute to bacterial growth in the RO tank, including the presence of nutrients in the water, changes in pH levels, and exposure to sunlight.

The growth of bacteria in reverse osmosis storage tanks can be prevented by flushing the tank with clean water on a weekly basis. The frequency of flushing depends on the size of the tank and the level of contamination.

Tanks that are flushed every two weeks are typically less contaminated than tanks that are flushed every month.

4. RO Membrane and Filter System Installation Issue

A properly installed membrane and reverse osmosis filter system can provide crystal-clear water for your home or office. However, if you’re having trouble with cloudy water, it may be due to an improperly installed membrane in the filter housings and the RO system.

When these systems are not installed properly, dirt and other particles can get through the filters and into your drinking water. This can cause all sorts of problems, from bad taste and odor to serious health concerns. You can check our guide on how to install the water filtration system the right way.

If you’re still facing issues with cloudy water, be sure to contact a professional to install your membrane and reverse osmosis filter system correctly. Otherwise, you could end up with contaminated water that’s unsafe to drink.

5. Air bubbles in RO systems

White particles that are basically trapped air bubbles are often seen in reverse osmosis systems due to the high pressure within the system. These bubbles can be trapped in the drain saddle, the membrane housing, or any other component of the RO system.

When water is forced through a membrane under high pressure, tiny air bubbles can be forced out of the water. These air bubbles will rise to the top of the tank and can create a cloudy appearance in the water.

Air bubbles makes RO water cloudy

While this may not be aesthetically pleasing while drinking water, it does not affect the performance of the RO filtration system and does not need to be addressed.

6. Too much Chlorine

There are other reasons for reverse osmosis cloudy water besides poor filtration. One common cause is too much chlorine.

Chlorine is a common chemical used to disinfect water and kill bacteria, but too much can cause cloudiness in the water. It can also be caused by high levels of dissolved solids, such as minerals or metals.

It is important to test your water for both chlorine and cloudiness levels to ensure that you are not drinking or using water that is unsafe.

7. Storage Tank is Full of Air

There is a possibility that the storage tank for the RO system is full of air and it needs to be bled to remove cloudiness in the water.

When does my RO system need maintenance or a membrane replacement?

If your reverse osmosis system is giving you cloudy water or producing sound, it’s time for a maintenance check or filter replacement.

Here are a few tips to help you determine whether your system needs attention:

1. Filters Are Dirty

Filters are Dirty Inside

If the filters are dirty inside, they need to be replaced. Check our review article on the Best Whole House Water Filter Cartridges to get one for your filtration system.

2. Membrane Needs Maintenance

Membrane Needs Maintenance

Make sure the membrane is clean and not clogged. A clogged membrane will reduce water flow output and produce cloudy water. Once you clean the membrane properly, you can get crystal-clear drinking water.

3. Check the Tubing, Housings, and Fittings for Leaks

If you find any leaks, they will need to be fixed before the system can be used again. Sometimes the ions push back resulting in cloudiness in water from the RO system is caused by an incorrect faucet fitting with an air gap.

Moreover, if the RO filter housings are not properly installed, there’s a possibility that the unfiltered hard water will enter the RO storage tank.

You can contact a technician to check and fix the leakage and air gaps from the plumbings.

4. RO Filter is New and Needs Time to Break-In

If you’ve just installed a new reverse osmosis system, give it time to break in. It may take a few days for the water to clear up completely.

5. Water Quality Needs to be Tested

Test the water quality with a test kit and see if the levels of contaminants in the water are within acceptable ranges. If they’re not, then it’s likely time to replace the membrane.

What to do if the cloudy water doesn’t go away from the RO System?

If your Reverse Osmosis (RO) water suddenly becomes cloudy, don’t worry. It’s a common issue that can usually be fixed with a little bit of maintenance.

The first step is to determine what’s causing the cloudiness.

Potential Culprits of Cloudiness in RO System

There are several potential culprits, including:

  • Dirt or sediment caught inside the filters;
  • Mineral buildup on the membrane;
  • Bacteria or algae growth;
  • Air Bubbles;
  • Calcium and Magnesium Buildup

Tested Solutions to Fix Cloudy Water in RO Filter

Cloudiness removed from RO Water

Once you’ve determined the cause, here are some tested solutions to fix it.

  • If it’s due to dirt or sediment, clean out the filters to produce clean water;
  • If it’s due to the mineral buildup, descale the membrane;
  • If it’s due to bacteria or algae, treat the water with chlorine or another disinfectant;
  • If it’s air bubbles, simply wait until the RO system is turned on until all of the air is dissipated before using the faucets.
  • If it’s due to the dissolved calcium and magnesium ions making hard water, install a water softener with the RO filtration system to completely remove all the dissolved minerals from the water. It’s a better option than always having cloudy tap water.

With a little bit of care and maintenance, your RO water should be clear and refreshing once again.

Can I stop air bubbles from forming in RO System?

Reverse osmosis systems can be prone to air bubbles forming in the water. This can make the water appear cloudy and can also reduce the efficiency of the system.

There are multiple solutions you can implement to help prevent air bubbles from forming:

  • Make sure that all of the fittings and seals on the system are tight and that all of the components are properly installed.
  • Check for leaks in the system and repair them as needed.
  • Don’t run the system too fast – try to keep the flow rate at or below 2 gallons per minute to produce pure water.
  • Use a quality filter with a higher flow rate if you need to increase the supply speed of your purification system.
  • Don’t let the water level get too low in the storage tank – always keep enough water in reserve to cover the membrane.
  • Flush the system with water for several minutes before use.
  • Avoid shaking or jarring the system while it is operating.

Why Is My RO Water Cloudy | FAQs

Is the cloudy reverse osmosis water safe for drinking?

Yes, the cloudy RO water is safe to drink, but it doesn’t look or taste as good as clear water. The cloudiness is caused by tiny particles that are too small to be removed by the filter. The particles are usually harmless, but they can include bacteria, minerals, and other organic matter.

How long can I store RO water without becoming Cloudy?

In general, RO water can be stored for up to two weeks without becoming cloudy. However, if the water is exposed to direct sunlight or high temperatures, it may become cloudy sooner. If the cloudiness is more severe, you will need to filter it before storage.

Is cloudy Reverse Osmosis water a signal that I should replace my membrane?

If your reverse osmosis water is cloudy consistently, it might be an indication that the membrane needs to be replaced. This is because the membrane is responsible for removing contaminants from the water, and when it becomes dirty or clogged, it can cause the water to appear cloudy.

If you have a sediment filter in place, it may help to purify the water in faucets, but if the problem persists, you will likely need to replace the membrane.


In conclusion, if you have noticed that your reverse osmosis water is cloudy, there are several possible causes, including air bubbles, high levels of TDS, and a fouled membrane.

The solution will depend on the specific cause, but it may involve flushing the system, replacing the membrane, or adjusting the TDS levels.

Maintain and clean your reverse osmosis system to prevent cloudy water and ensure it is functioning correctly so you can enjoy clean, clear, and healthy drinking water.

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