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Why Is My Reverse Osmosis Constantly Draining: Solved (2024)

Why Is My Reverse Osmosis Constantly Draining 8 Reasons With Practical Solutions [2022]

Are you facing the problem of constant drainage and water wastage and have always wondered: “Why Is My Reverse Osmosis Constantly Draining?”

Then, understand this:

The Reverse Osmosis system always works under pressure, and its drainage mainly results from: 

  • Extremely low pressure of the tank
  • The breaking of the shut-off valve (also called the check valve).

But, there are also many other reasons behind this drainage. Stay with me as I’ll show you 8 common issues that result in RO water drainage (along with their solutions!).

How Often Should A Reverse Osmosis Drain: Clearing The Basics

A Reverse Osmosis tank is usually drained at night before bed. It can make the tank refilled within the next morning. And this process is followed every two weeks.

The water drainage enables the reverse osmosis system to turn its tank’s water completely. As soon as you use a small portion of water from the tank, the system refills the same portion of water into it. 

Thus, the tank never gets fully empty, and if it doesn’t get fully empty, you can’t refill the water inside the tank.

What this means is:

If your water requirement in a day is low (you live alone or your family is small) and the tank is not emptying anyhow, it is necessary to drain the RO tank every 2 to 3 weeks. By doing that, the whole water is renewed, and the water quality is ensured to provide you with safe drinking water. 

Also Read: 5 Top Tankless Reverse Osmosis Systems

Here’s the worst part: At times, water drains abnormally [in which the tank’s water continuously keeps on running to drain] with a noisy gurgle.

Moreover, the primary concern is that since the water is not used for a few hours, it will stop running towards the drain. This situation arises when the reverse osmosis drinking water supply network washes out its waste while filling the tank.

You have to follow a systematic approach for troubleshooting your problem. The drain flow rate test helps you determine the amount of draining water in the RO.

Don’t worry as it is the time for…

Why Does My Reverse Osmosis System Run Out of Water: A Cheatsheet

ReasonsHow Common is the issue?How easy it is to fix?Troubleshooting in brief
Deficient Storage Tank Pressure Very commonSuper EasyRe-pressurize the tank
Inlet Valve/One-Way Valve Is BrokenVery commonEasyTest and replace the valve
RO Membrane Is Blocked/DamagedLess CommonMediumFlush regularly, replace the membrane
Water Pressure Below Required LimitCommonEasyEnhance the pressure/ install a booster pump
Voltage Switch BrokenCommonEasyReplace the voltage switch
Tank Air Bladder DamagedLess CommonMediumReplace the tank
RO System Improperly InstalledLess CommonMediumRecheck, dismount and reinstall it
Flow Restrictor Is DamagedLess CommonSuper EasyRemove and replace the restrictor
Also Read: Reddit Discussion on RO Constantly Draining 

1️⃣ Deficient Storage Tank Pressure

The pressure within the storage tank is the first thing one should examine in a reverse osmosis drinking water system constantly draining water. It is because the storage tank’s pressure issue acts as the culprit in most RO water-draining cases.

And, in case the problem is not due to the low storage tank pressure, you must check the automatic shut-off valve/ check valve. 

I have suffered from the problem of the RO system draining at home and was a bit confused about how to deal with it; how to stop the excess water from flowing to the drain! After all, the gurgling noise of the draining water is very irritating. Also, the water’s odd or strange taste due to the drainage is intolerable. I tried many ways to detect and solve the problem but without success. 

At last, I learned the actual reason and the hard way of solving the problem. I called a plumber, and he explained everything about RO water drainage. 

What he explained to me was as follows:

After passing through the RO membrane, water is usually stored in the RO storage tank. The reverse osmosis drinking water system comprises a water pump that generates high pressure, pushing the water through the RO membrane.

The system keeps running smoothly as long as the pressure within the storage tank is maintained. Also, the air pressure within the tank, when it is empty, must be between 6 – 8 PSI

Whenever the PSI levels of pressure inside the tank drop too low, it results in water drainage of the RO system. You should test the pressure with a pressure gauge, and if the PSI of pressure is lower than 6, you are required to increase the pressure within the tank. You can also test the feed pressure with the same device. 

To troubleshoot the deficient storage tank pressure problem, I repressurized the tank using 2 tools – 

  • A pressure gauze and
  • A bicycle pump

How To Fix It? 

Follow step by step:

  • First, turn off the water supply and then shut off the feed valve of your RO pressure tank. Now, disconnect the tank. Transfer it to an area of your home where you can drain its remaining water. 
  • Though initially, the water will pass out quickly, the water flow will decrease after some time. Once its flow decreases, take a bicycle pump to insert air within the tank.
  • Keep pumping with the bicycle pump or tire pump to see water coming out of the tank. The water will stop coming out only when the tank becomes empty. 
  • Bring a pressure gauge to check the pressure inside the RO tank. If the tank’s pressure is less than 6 psi, you must repressurize your RO’s air pressure valve with the pump/compressor. While pumping air within the tank, have a watch on the PSI gauge, so the tank doesn’t get ruptured due to your over-pressure. 
  • As the pressure reaches the 6-8 PSI level, stop pumping. Shut down the pressure valve. Now, attach your RO tank to the system itself as it was before by replacing the removed parts. Turn on the water flow and ensure that the water drainage problem and the loud noise of draining water will be solved. 
Also Read: The Honest Comparison Between SpringWell and Pelican Whole House Filters 

2️⃣ Inlet Valve/One-Way Valve Is Broken

The water inlet valve or the ASO (Automatic Shut-Off) valve allows pure water or fresh water to enter the tank. This valve only enables pure water to pass within the pressure tank. As the RO tank becomes full, the water inlet valve gets a trigger to stop the water flow, and hence, it gets closed. 

As per my experience, a fault in the water inlet valve may make it stay open. As it stays open, the unwanted and additional pure water keeps flowing into the reverse osmosis drinking water system. Due to the large discharge aperture, pure water travels very quickly into the wastewater channel. 

One-Way valve, also known as the Check valve, works by preventing the rejected water of the RO from draining. With the breaking or damage of the check valve, the water gets pushed within the drain pipe due to the water pressure accompanied by the strange noises of draining water. As a result, water continuously drains on. 

To detect these valves problem, do the 1st valve checking test as under:

  • First, fill up the tank completely. Try to lift the tank. By doing that, you will understand whether the tank is full. 
  • Now, draw a few glasses of water (say 2 or 3 glasses) from the faucet of the RO. It will reduce the storage tank’s pressure and restore the RO system’s initiative to process more water for refilling. 
  • Close the RO’s tank valve to imitate a full tank and wait for a few minutes (say, five minutes). 
  • Now, check if water is still flowing with strange noises towards the drain line even after closing the tank valve or if it has stopped flowing. Do this by putting your ear close to where the flowing sound is coming from. You can also check the same by removing the drain line from the drain saddle or drain tube. 
  • If you see that the water is continually flowing down the drain, then any of the two valves (inlet valve or one-way valve) is broken. 

In such a case, you must go for the 2nd valve checking test:

  • Give the tank some time before it gets refilled. 
  • Open the tank’s valve and close the valve for feed water.
  • Now, check out if the water is streaming towards the drain line or has stopped flowing by putting your ear close to the place from where the flowing sound comes. You can also check the same by removing the drain line from the drain saddle. 
  • If the water is still draining, it must flow from the storage tank, indicating that the broken valve is none other than the check valve. However, if no more water is draining, then the valve that is broken is the Automatic Shut-off valve. 

After the plumber told me about this method, I tested my RO system valves in the same manner.

How To Fix The Problems?

To fix the problem of the broken ASO valve:

  • First, dismount the RO system for better access to your RO unit’s backwards-positioned valve. 
  • While navigating the valve, please pay attention to its configuration. It will help you to install the new valve correctly. 
  • Many tubes are connected to the automatic shut-off valve. Pull them from it and attach them to the newly bought valve. The new valve must be connected to the tubes precisely like the old one. 
  • When your tasks are over, connect the reverse osmosis unit back. 
  • To fix the broken check valve problem, replace it with a 90-degree Check valve in the following manner:
  • Ensure that you choose the appropriate valve according to your pipe’s size, orientation, flow rate, and water flow direction. If your valve doesn’t conform, it may experience inefficiency and unnecessary wear/tear. 
  • Notice where you need to install the valve in your pipeline. The valve must be at least 5 diameters away from your elbows and other valve fittings. It reduces any expected future potential turbulence.  
  • Place the valve in such a manner that it aligns with the marked-up arrow on the valve (known as the flow arrow). Aligning it with the flow of water will give you zero trouble in the future. 

3️⃣ RO Membrane Is Blocked/Damaged

The reverse osmosis membrane works by filtering unwanted residue to remove the bad taste of water. So, debris, dirt particles, contaminants, and other impurities can accumulate on the membrane over time, which eventually results in its blockage.

The clogged filters make it difficult for pure water to pass through them. Instead, the water directly flows out to the system’s drain pipe. Clogged filters or damaged membranes can thus make the entire system fail. 

How To Fix It? 

You can consider any of the following solutions:

  • Replace the membranes frequently.
  • Install an extra pre-treatment system in the RO, such as a water softener to remove hard minerals from your water. 
  • In case there is more than one bad RO membrane, replace them.

4️⃣ Water Pressure Below Required Limit

Feed water pressure of the RO below the required level is another reason for water drainage in an RO system. If the pressure of water drops to 40 PSI or below that level, this problem arises. 

How To Fix It?

  • Make use of a pressure pump or booster pump to bring the feed water pressure to the required level
  • With each pump of the device, the feed water pressure will increase and match the necessary level.

5️⃣ Voltage Switch Broken

Draining water in RO may also happen due to breaking the filter’s high-pressure switch. The RO system functions by generating clean water as well as wastewater continuously.

If it is usually working, the high-voltage switch turns off automatically, and the power gets disconnected as soon as the machine is full of water. 

However, when a problem arises with the RO’s high-pressure switch, the system keeps generating wastewater with the machine functioning. Since the storage bucket’s water doesn’t get filled, it flows back within the port of wastewater. 

How To Fix It: 

  • Check the voltage switch.
  • If broken, replace it.

6️⃣ Tank Air Bladder Damaged

Even if the storage tank’s low pressure is detected after fixing it, you may not solve the draining problem. After some days, again water may drain from the RO tank. If the case is so, test the air bladder to see if it is damaged. 

It may happen that due to:

  • The irregular maintenance of the RO unit
  • The excessive water pressure causing rupture in the RO air bladder. 

Important to note:

If the reason is a damaged air bladder, very little or no water will stream, even when the RO tank is full. 

To Test a Damaged Air Bladder: 

  • Pour 1 cup of water into the tank to normalize the pressure level. 
  • If you notice that the water flow has decreased, you can be sure that the air bladder is damaged.

How To Fix It: 

  • A damaged RO tank air bladder cannot be repaired or replaced separately.
  • To fix the drainage problem, replace the complete RO unit. 

7️⃣ RO System Improperly Installed

Sometimes, the slightest misplacement in the installation of the RO unit may result in significant issues like water drainage. It is always better to install it by hiring a professional installer than doing an improper installation yourself.

And, in case you don’t wish to hire an installer for the job, follow the product’s instructions word by word during your device installation. 

How To Fix This Problem?

  • If there is an installation error in the unit, dismount it.
  • Double-check every instruction in the product’s user manual and reinstall it.

8️⃣ Flow Restrictor Is Damaged

A flow restrictor gauges how much water drains from the tank and when. When the flow restrictor wears out or gets damaged, the high-pressure water streams quickly into the drain. As a result, the system’s pressure reduces. 

How To Fix This Reverse Osmosis Troubleshooting Problem?

  • Replace the flow restrictor annually before it is worn out. 
  • For replacing it, locate the restrictor and turn off the tank and feed water valves. 
  • Disconnect the black-colored tubing from the Reverse Osmosis system.
  • Withdraw the damaged restrictor or the clogged flow restrictor from the black-colored tubing.
  • Replace the old flow restrictor with a new restrictor. Reconnect the black-colored tubing to the RO system.   

Other Common Problems In RO Systems [Smart Troubleshooting]

ReasonsHow Common Is The IssueHow Easy To FixTroubleshooting In Brief
Reverse Osmosis tank is not filling upCommonEasyIncrease your entire home’s internal pressure/ reduce the pressure of the tank 
High TDS In RO WaterLess commonMediumApply pressure to the influent water stream, and reverse the process of natural osmosis
No water going down the drainLess commonEasyIncrease the water pressure, increase the water volume 
System/Faucet LeakingLess commonMediumTighten all connections; the tubing must be pushed into their ports and the drain saddles and valves.   

1️⃣ Reverse Osmosis Tank Not Filling Up

The extremely high pressure of the tank or extremely low pressure of the feed water results in the RO tank not filling up. 

The normal pressure of the empty tank must be within 6 – 8 PSI. You can test the pressure of the tank by using a standard bicycle gauge. 

How To Fix It?

  • When I face this problem at home, I initially reduce the pressure if it becomes exceptionally high.
  • If the pressure is extremely low, I increase it by using a pump.
  • You may also increase your entire home’s pressure to fix the problem. 

2️⃣ High TDS In RO Water

High TDS in RO water indicates unpurified water, which is a critical problem in an RO system. This problem happens because of any of the following reasons: 

  • The change in the water source’s quality
  • The post-filters add minerals to the purified water.
  • The reuse of rejected water by the RO (in countertop RO systems)
  • The damage to the RO membrane
  • Incorrect testing 

How To Fix It?

  • Test once again properly
  • Replace the RO membrane of the membrane housing. It helps many times, as I learned from the plumber.
  • Apply pressure to the water stream (that is influent) to overcome osmotic pressure
  • Reverse the natural osmosis process by filtering out the salt ions to 0.0001 microns. The process removes about 95 to 99 percent of Total Dissolved Solids (TDS), organic matter, suspended solids (of about 99 percent), and bacteria.  

3️⃣ System/Faucet Leaking

A leaky faucet/system causes water to drip. It indicates that either one or more system parts are loosely fitted. 

How To Troubleshoot It?

  • When I faced water leakages in my reverse osmosis faucet system, I tightened all the connections thoroughly so that no loose connection existed. The thing worked for me as the leaking stopped.
  • But if your faucet is still leaking, push the tubing of your system further into the ports. Push the valves as well as the drain saddle. Unscrew the filter housing, screw it and tighten it back. Your leakage will stop. 
  • Remember, there is no solution if the leaking water comes from the faucet stem’s bottom. You can’t even replace the piece in such a situation. 

4️⃣ No Water Going Down The Drain

Sometimes, the slow water flow rate of the RO system gives us much stress. And the same tension doubles when no water goes down the drain at all. It results in an empty RO drain with no drain water.

The reasons include:

  • Low water pressure
  • Or low water volume

How To Fix The Slow Water Flow Or No Water Flow Issue:

  • Increase the water pressure just as I did when I faced this problem. 
  • Or increase the water volume. 

Why Does Reverse Osmosis Drain Water: FAQs

How long should a reverse osmosis drain? 

RO system usually drains running water during the production process. However, when zero water usage happens even after 3 to 4 hours of the passage of time, no draining of water happens anymore. 

How do you check RO membrane is working or not? 

To check a RO membrane’s workability, one must use a decent-quality TDS meter (a conductivity tester). It will show if the membrane is in working condition or not.  

How do you know when to change reverse osmosis filters?

In general, you must replace the reverse osmosis filters after every twelve months.

Why is my water filtration system leaking?

Your water filtration system may leak due to the following:

1. Tube not wholly inserted into its plug 
2. Quick-connect fittings issues such as Missing lock sleeve
3. Tightening the housing/ cap too tightly/ too loosely

Why does my faucet drip after I turn it off?

Faucet leaking happens because either one or more parts of the system are loosely fitted. 

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