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10 Common Reverse Osmosis Problems + Solutions(Fix your RO System)

10 common problems in ro systems and how to fix them

Reverse osmosis systems are known for their unique ability to provide families with pure water. They are also known for the many problems they tend to have once they have been installed.

Please note any problem you run into should be resolved as soon as possible. Ignoring an issue could only lead to bigger issues later on down the road.

To avoid panic and prevent you from making frantic calls, we familiarize you with some problems you are likely to encounter with your Reverse Osmosis system and their probable causes.

With that being said here are the most common reverse osmosis problems you will run into and how to fix them.

Reverse Osmosis Problems + Solutions for Troubleshooting

1. Noisy Drain and/or Faucet

Common causes:?low pressure, damaged bladder, storage tank pressure too high, feed water pressure too low, poor membrane, clogged filters, bent tubing, empty storage tank, closed valves

If you are using your reverse osmosis system for the first time, or you have recently had some of the filter cartridges replaced, there is a good chance the drain line will make a little noise.

This happens when air is being pushed out of the system. For the most part this is nothing to worry about.

However, if the noise continues after a day or two you may want to have a look around the system to make sure everything is properly hooked up.

Start by checking the tubing and making sure it is set straight. Look for any restrictions in the drain tube that could be interrupting the flow of water.

If you find that the system is still noisy you may need to check the entire system for gaps. If there are any faults be sure to have them corrected as soon as possible.

2. Reverse Osmosis water flow is slow

Have you had your reverse osmosis system installed for a few years now? Have you enjoyed waking up every morning to a nice refreshing glass of water?

If so you would probably be devastated if you woke up one morning to find your beloved reverse osmosis system has a very slow water flow. In some cases there may be no water flow at all.

If you have little to no water flow it is usually the result of one of two things. Either the water pressure is low or the volume of water is low.

This type of problem is usually caused by a storage tank that has malfunctioned. The storage tank has an air bladder that increases the pressure when more water starts to flow into the tank.

If the bladder malfunctions due to a leak or break it won?t be able to build up enough pressure in the tank.

As a result you will experience slow or no water flow.

To solve this problem you will first need to check the tank to see if its full. If the tank is full it will weigh around 20 pounds. If the tank is empty it will weigh less than 2 pounds.

If the tank is full that usually means the problem is coming from the inside.

To fix it you will need to pressurize your reverse osmosis tank.

Here is how to do it?

Step 1

Start by shutting off the cold water supply to the system.

Step 2

Make sure the storage tank valve is closed.

Step 3

Disconnect the tank and take it outside. Once outside you will need to open the tank valve and drain out all the water.

When you first open the valve the water will start to pour out quickly. However, after a few minutes it will start to slow down and eventually become nothing more than a trickle.

Step 4

Don?t be fooled by the trickle of water. There will still be quite a bit of water left inside the tank. To get it out you will need to use a bicycle pump or a compressor to pump air into the pressure vessel.

Every time you pump you will notice more water pouring from the tank.

Step 5

Once all the water has been removed from the tank you will need to measure the pressure inside using a pressure gauge.

The gauge should read between 6 psi and 8 psi.? If the pressure falls below that you will need to pressurize it again.

Step 6

Once you are done pressurizing the tank you can reconnect it to the reverse osmosis system. Once reconnected refill the system by opening the tank valve and the feed water valve.

If after a few days you notice the water pressure falls again, this would mean the air bladder is malfunctioning and the whole tank will need to be replaced.

3. How to tell if the reverse osmosis membrane is bad

Slow water flow may also be a sign that the low feed water pressure is too low. This is usually caused by your reverse osmosis membrane going bad because of clogged filters.

When the membrane is constantly being forced to process water that is exceptionally hard, this will lead to it becoming clogged up.

To fix this issue you can either replace the membrane more often or you can install a water softener to help remove certain minerals from the water before it goes through the filtration system.

If the low water flow is being caused by clogged filters then you will need to have them replaced as well.

Clogged filters tend to be more common in new homes where high levels of debris and sediment temporarily fill the plumbing system.

Slow water flow can also be a result of bent tubing. When tubing is bent the pressure in the tank gets reduced and the flow of water gets restricted.

Check the tubing and if any water lines are bent straighten them out immediately.

4. Reverse osmosis constantly drains

Common reasons: Storage tank pressure too low, tank air bladder damaged, broken shut-off valve, broken check valve, feed water pressure low, incorrect installation, degraded membrane, worn out flow restrictor

All reverse osmosis systems, including whole house reverse osmosis systems, work on pressure. Anytime the storage tank is full and there is full pressure the automatic shut off valve gets automatically triggered.

Once this happens water stops flowing into the system and rejected water stops flowing down the drain line.

If the shut off valve or check valve are not functioning properly water will continue to flow down the drain line.

As a result your reverse osmosis system will constantly drain, waste a ton of water, and make a lot of noise.

To fix this issue there are two potential tests you will need to run. But first you will need to measure the pressure in the tank using a pressure gauge.

Make sure the tank is full before you try to measure the pressure. You will know its full when you try to lift it.

The pressure inside the tank should be between 35-40 psi. If the pressure falls within this range then that means either the shut off valve or the check valve need to be replaced.

Here are the two tests you can perform to see if the valves need to be replaced:

Test #1

This test will help you determine if the automatic shut off valve and check valve are functioning properly.

  1. Lower the pressure in the tank by letting about 20 oz of water flow from the faucet. This will force the system to start processing water to refill the tank.
  2. Mimic a full tank by closing the tank valve.
  3. Give the system 5 minutes to process the water.
  4. The fourth and final step is to check to see if the water has stopped flowing down the drain line.

You can do this by listening to what the system is doing, or by removing the drain line from the drain saddle.

If the water has stopped flowing that means the valves are functioning as they were designed to do so.

If on the other hand the water continues flowing down the drain, this means one of the valves is broken.

If the valves are broken continue on to the second test.

Test #2

  1. Keep the tank valve open while the tank is refilling.
  2. Turn off the feed water valve.
  3. Check to see if water is still flowing down the drain line. Refer back to step 4 in the previous test to see how this is done.

If water is still flowing it means it?s coming from the storage tank. This indicates the check valve is broken and needs to be replaced.

If no water is flowing that means the automatic shut off valve is no longer functioning properly and will need to be replaced.

5. 3 More reasons your reverse osmosis system is constantly draining

  • The feed water pressure can also affect the flow of water. If the feed water pressure is 40 psi or lower, use a pressure pump to increase the pressure to the right level.
  • Did you hire a professional installer or did you try to install the system yourself? Improper installation is one of the biggest reasons water will continue running down drain.

While we always recommend hiring a professional, we realize that?s not always feasible. If you plan on installing it yourself make sure you take your time and carefully read through all instructions.

Make sure all system parts are in the right position before operating the system.

  • Over time the flow restrictor can wear down and cause the system to continue to run on a constant basis. To fix this issue simply replace the flow restrictor.

6. Dripping or Leaking Faucet

Have you noticed your faucet is dripping or leaking for no apparent reason? If so this may be a sign that some of the system parts aren?t fitted properly.

Stopping the dripping and leaking is a simple as inspecting the machine and making sure all fittings are tightened.

Check the tubing to make sure it is pushed all the way into the ports, valves and drain saddle.

If you notice the leaking is coming from the bottom of the faucet stem, the only way to fix this is by replacing the piece.

7. Bad Taste and Odors In The Water

Common causes:?Degraded membrane

There is nothing worse than wanting a cold glass of water only to find the taste and odor are very unpleasant.

And while the purpose of a reverse osmosis system is to provide you and your family with pure drinking water, its not uncommon for this type of system to add a strange taste or odor to the water.

Unfortunately there is only one way to prevent this from happening and that is to be willing to invest in a good reverse osmosis system.

After using the system for several years it is very common for filtered water to start turning a bit cloudy.

Cloudy water is usually a result of biofilm accumulating in the various stages of filtration. The only way to get rid of biofilm is to immediately replace all clogged filters and any membranes that are fouled.

Once you have replaced the filters and the membranes make it a point to continue replacing them every 6 to 12 months.

By replacing these components on a regular basis you can prevent germs from accumulating in the reverse osmosis system.

To prevent germs from accumulating in both the filter unit and the water flowing through it, consider investing in a system that allows you to dispose of both the filter and the filter housing at the same time.

Please note these type systems are usually more expensive than regular systems. The maintenance costs will also be a little higher.

However, the extra cost will be well worth it being that you won?t have to worry about germs getting into your drinking water and causing potential health issues.

To extend the life of your unit and keep your family safe we recommend doing maintenance on the system a minimum of twice a year.

Make sure you clean it exactly as the manufacturer?s instructions tell you to.

8. Beware of Unused Water

Another source of bad tasting water or water that has an odor to it is unused water. If water is stagnant for an extended period of time bacteria will start to grow.

Anytime bacteria starts to grow that can affect the taste and smell of the water.

If your reverse osmosis system has been sitting idle for a while, take the time to flush the entire system, including the storage tank, two times before using it again.

This will ensure anything that has built up in the filters and tank will get flushed out.

9. Air Gap Faucet Leaking

Common causes:?Loose connection, damaged faucet stem, drain line clogged, drain saddle shifted

Have you noticed water coming out of the hole of the air gap faucet? If so this is known as an air gap leak and it is very easy to fix.

An air gap leak happens when the drain line becomes blocked with debris that has accumulated in the drain.

The purpose of the air gap is to prevent drain water from flowing back into the reverse osmosis system.

During normal operation the water will flow from the storage tank up to the faucet. The water will then fall through a small pocket known as the ?air gap?.

If the drain line starts to clog it will create back pressure. This back pressure will push the water through the faucet and it will get all over the sink.

While this may sound bad, fixing it is not as difficult as you may think. All you have to do is clear out the drain line so that water is no longer restricted and able to flow freely again.

This can be done using either a wire brush or a pipe cleaner. The end connected to the drain saddle is the end you want to clean.

You should also clean the drain saddle as stuff tends to grow inside of it as well.

Drain saddles are also known to shift during operation. If the saddle shifts that too can restrict the flow of water.

After you have cleaned the drain line take a few seconds to check the drain saddle. If it has shifted realign it so that the drain saddle is in line with the drain line hole.

10. Preventing an Air Gap Leak

While it?s impossible to completely eliminate the chances of an air gap leak happening, there are a few things you can do to ensure they don?t happen on a regular basis.

The first thing you can do is avoid throwing big chunks of food down the drain. This is probably one of the leading causes of clogged drains.

Instead of throwing food down the drain put it in a small plastic bag and throw it out with the trash. This extra step can prevent a lot of issues in the long run.

The second thing you should do is treat your drain line on a regular basis. All you need to do is pour a little natural cleaner down the drain and you will be good to go.

Doing so will help dissolve any potential blockades before they become a serious problem.

If you replace any filter cartridges the air gap faucet may make some noise for a day or two. This is very common and nothing to worry about.



And there you have it, ten of the most common issues you will run into when using a reverse osmosis system.

When it boils down to it, most of these issues can be avoided by doing maintenance on the system once or twice a year.

Doing regular maintenance will not only ensure your reverse osmosis is always running smoothly, but it will also save you money as you will be less likely to have to deal with a serious problem.

Investing in a good system is also important. The best systems don?t break down as easily as systems that aren?t made using quality parts.

Just because you?re on a budget does not mean you can?t afford a decent reverse osmosis system.

The key is to do plenty of research to make sure it is manufactured by a reputable company. Check out sites such as and do a little comparison shopping.

You are sure to find a system that not only fits your budget, but that also has most of the features you desire.

28 thoughts on “10 Common Reverse Osmosis Problems + Solutions(Fix your RO System)”

  1. I just started my 2 year filter change (sediment, pre-carbon, and post -carbon) and discovered that the old sediment and pre-carbon cartridges are covered in a thick yellow-orange wax. This waxy stuff was thickest at the bottom of the cartridges and in the bottom of the filter housing. What is this, and should I be concerned? I carefully washed the filter housings and installed the new filters and re-installed onto the base unit.

  2. I have a GE RO system. we have been enduring a drip drip noise in the drain line. Suggestions?

    where do I find “clean silicone grease”?

  3. My system ran out of salt,and the system stopped. It has been sitting for several months and we haven’t done anything with it. Is there an automatic shut off or did we do permanent damage to the system by letting it run out of salt?

  4. i just installed a new kitchen faucet. During installation, I turned off the R.O. system. After installing my new faucet, I saw some black stuff come out of the faucet and shortly thereafter, my water pressure quickly decreased. Now I have minimal water pressure even though I turned the R.O. system back on? I checked to make sure the water lines leading to the new faucet weren’t pinched, but still have minimal pressure through the new faucet??

  5. My tank is barely filling up (5 gallon tank and less than 1 gallon will go in it). This happened after changing all filters. I emptied the tank and set the PSI to 7 then hooked it back up. I still get barely any water.

    Could this be a problem with new membrane?

  6. I have a 4stage reverse osmosis found that my tank does not fill.changed tank with new one same problem.changed out membrane still same i brougt brand new 4stage still same probkem tank wont fill what can cause this help

    • sounds like you have too much air pressure in the storage tank . let out some air til the tank has 7-8psi . use a tire gauge to set the air pressure.

  7. changed out all filters and membrane a couple weeks ago. I am getting terrible water 178 to 215 PPM in water was 54 ppm before filter and membrane change. I double and triple checked connections and sequence of hookup. Does anyone have an answer for this.


    • always purge your filters before installing the membrane.its possible that the membrane is fouled by the loose carbon from the filters .

  8. Where can I get O rings for my RO system housing sumps. It’s a CE 5 stage system. I tried the APEC rings as they are the right OD and ID, but they are only 1/8″ thick. My system needs a slightly thicker O ring, about 3/16″. Appreciate any help, thanks,…Gary. 4353596332

  9. Is there an effective way to remove the reverse osmosis microbubbles? like, if I put a filter after the reverse osmosis filters? would it remove the bubbles?

  10. I have a 6-stage R.O. system (2 polishers).
    I’ve had the system for about 8 years and routinely change out filters and membrane.
    On my recent change-out I replaced the tank with a new one of the same(P.A.E. ro-132).
    Water flows to the tank (flows freely when not connected to tank ball valve and that valve is perfect), but the new tank will not accept any water.
    Pressure on the new tank arrived with 5.0 psi.
    Building psi is 50.
    I’m stumped.

  11. I have a GE RO system, I recently had an issue with the tank pressure and had to repressurize. After doing so, the tank was filling and the system was working properly, but after about a week, I could only get about a cup of water out of the system and then no flow at all. I then rechecked the pressure in the tank and also cleaned the flow control. Same result, tank filled, system seemed to working good, then little to no water and it doesn’t seem to fill, can only get a cup of water out. Any ideas on what the issue might be? I have tried to not use the sytem to see if it will completely fill, but it doesn’t seem to matter how long I wait.

  12. I have a 4 stage RO for 9 months. Water started coming foamy on the surface. 4 Filters were changed but the foamy water still is on the surface. What is the problem and how to solve it?

  13. My RO water pressure was very slow so I repressuurized the tank and water stopped flowing all together. I thought it was the automatic shutoff valve so I depressurized the whole system and tried it again and still no water. Any ideas before I have to call someone?

  14. APEC 5 stage – ordered filter replacement kit with new unit. A year later replaced filters. The 3 filter below had film, cleaned and disinfected, dried out, no problem.
    The RO membrane was a whole other story. The faucet runs like there is no RO at all. TDS indicates no RO taking place for sure.
    The Documentation is lacking. Just one image of the RO, but nothing to really help.
    Called, sent photos, video to APEC support.
    It was working before I replaced the filters. I have replaced many filters before.
    I don’t know how to test the 4 way switch on this unit. Not sure if support does either.
    Hate to throw away something because of poor documentation.

  15. Undocumented – the black line is undocumented and has a flow restricter.
    Well, I moved my RO unite in the basement and cut my own black line to reach
    Here is the bad part. I ordered the spare 4 filters (including the RO) with the new unit.
    The APEC ROES-50 manual page 20 shows a different filter – very different!
    It also indicates a wrong way to install.
    But, the tech at APEC says the filter after a time, can go bad.
    So, I ordered another $36.00 filter to try and replace it.

    I just don’t understand in this day of Internet, why this much documentation can be missing or wrong! It isn’t the $50 of parts and shipping so much as the many hours of trying to troubleshooting and waiting my turn on the support line. Maybe 18 hours.

  16. Just replaced all filters elements on a culligan reverse osmosis system, tank 7 psi, and after two hours of operate the lead line into the polishing filter popped out, making loud noise. What is causing the pressure to pop this line out of filter?

  17. I have a red residue build up at the very tip of the nozzle. Every month I have to swab with a Q-tip to clean. However, today I swabbed and also discovered metal chips!! I change my RO filters every 6 months. I have a whole house twin filter system in the cellar; 5 micron charcoal and that pours into a 1 micron filter. Thus the RO gets filtered water. Yet I get this residue one month after changing the RO unit. What is going on?

  18. I was never aware that a noisy faucet is a sign that our osmosis needs to be repaired. The other day I noticed my dad’s reverse osmosis system was giving out a loud noise and had a leaky faucet. I will ask my dad to have it repaired or serviced.

  19. Can’t find on-line any troubleshooting for issue, when reverse osmosis bust pump keeps running, without flows water to drain.
    Could you explain what to do in this case?


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