NU Aqua Reverse Osmosis Systems Why Do I Need to Flush My RO System?

The maintenance of your Reverse Osmosis (RO) System is crucial to ensure high water quality and system longevity. Flushing your RO system aids in that as it involves cleaning the system's filter and membrane. So how and why do we flush our RO systems?

The Importance of Flushing RO Systems

  • Preventing Membrane Fouling and Scaling: Fouling occurs when contaminants such as organic compounds or fine particulate matter build up on the membrane surface while scaling involves minerals build up such as calcium and magnesium. Flushing the system helps washing away these particles preventing accumulation and making sure the membrane's efficiency is maintained.
  • Ensuring Optimal Performance: Flushing the system avoids the quality of the filtered water from deteriorating and ensures that the water's flow rate does not decrease. 
  • Extending the Lifespan of the RO System: Accumulation of contaminants and mineral deposits, put additional strain on the RO system aside from compromising the quality and the water's flow rate. Increased strain on the system can lead to more frequent repairs and even premature replacement of the filters or the system. By flushing the system, it significantly helps in extending its lifespan and makes an effective preventative maintenance measure.

Consequences of Not Flushing Your RO System

  • Decreased Water Quality and Purity: RO systems' primary function is to provide clean and pure water. When sediments and mineral deposits accumulate due to the lack of flushing, it compromises the RO membrane's capacity to filter efficiently. Thus, getting a higher risk of getting exposed to higher quantity of contaminants.
  • Increased Operational Costs: The system's performance will drop due to the clogged or fouled membrane. The membrane will have to work harder in order to produce the same amount of filtered water which in turn increases energy consumption. Operational costs will also increase as the filters and membrane will need more frequent replacements than necessary.
  • Potential System Breakdowns and Costly Repairs: Worse comes to worst, not flushing the RO will risk system failure. In some cases irreversible damage to the membrane and other critical components of they system my occur due to the build up of contaminants. As such, in some cases, the entire system may need to be replaced prematurely leading to unexpected costly repairs.
  • Compromised System Lifespan: More than the immediate effects on water quality and costs, the lifespan of your RO system is also extremely affected. Without flushing the system, all of the components can degrade faster than anticipated resulting to shortened lifespan and more frequent need to replace parts. 
damaged filters and ro membrane

How to Properly Flush an RO System

Here's how to flush your NU Aqua Platinum Series RO System:

  1. Turn the tank ball valve on your tank to the off/close position. This is to prevent any loose filters particles from entering your tank.
    Tank Ball Valve Open and Close position
  2. Open your cold water line fully then gradually open your feed water adapter.
  3. If your system is equipped with a booster pump, make sure to plug in the electrical cord into your outlet.
  4. If your system is equipped with a UV filter, make sure to plug the electrical cord into your outlet.
  5. Open your reverse osmosis faucet. It may take up to 10 minutes for water to begin to drip from the faucet. Once water begins to drip, let it run for 30 minutes.
  6.  After 30 minutes, close the reverse osmosis faucet and wait 10 minutes for the system to pressurize. Once pressurized, check each fitting and connection for leaks. If no leaks are present, proceed to step 7. If you do have a leak, locate the source and turn off the cold water valve. Address the leak, if unable to resolve, contact customer support for assistance.
  7. Turn the tank ball valve to the open position.
  8. Wait for the tank to fill, this will approximately take 1-3 hours.
  9. Once the tank is full, flush the system by opening the reverse osmosis faucet until the storage tank is completely drained. The water flow will be reduced to a slow trickle once the tank is empty.
  10. Repeat steps 6-7 three to five times to ensure your system is properly flushed. Once completed, your system is ready for use.

For NU Aqua Efficiency Series Tankless RO Systems, the steps are similar but are a bit easier:

  1. Check that each connection is fully inserted into its fitting and has a retaining clip installed.
  2. Open the feed water valve slowly then wait 1 minute and check for leaks at every connection. If there are any leaks, close the feed water adapter and open the reverse osmosis faucet to relieve pressure from the system. Remove the leaking connection and reinsert the tubing. If this does not resolve the issue contact customer service for assistance.
  3. Plug the power supply to the power inlet on the back of the reverse osmosis system then plug the power supply to the wall outlet.
  4. Hold down the power button on the front of the system until the light next to the icon turns solid.
  5. To flush the system, open the faucet and allow the water to run for 30 minutes. This will flush the new filters of any loose filter media. It’s normal for your water to have a slight gray tint during this process and will go away.

To test your filtered water's TDS levels use a TDS meter and note that when testing it is important to first flush out the water with the TDS Creep by discarding the first 1-2 cups of water from the system and only test the water that comes after. TDS Creep refers specifically to the gradual increase in TDS levels in filtered water which can be due to initial set up of the system and/or long idle time of the system meaning it was not used for a prolonged time.



Regular flushing is a simple yet critical maintenance task that significantly affects the health of your RO system and the quality of your water. Choose reliable systems such as the ones from NU Aqua and adhere to proper maintenance protocols, this will ensure efficient operation and longevity of your system.

Visit NU Aqua Systems for more detailed product information and expert advice.

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