How Long to Purge a Reverse Osmosis System
Written by: Gene Fitzgerald // Last Updated: Sep 26, 2023
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Purging a reverse osmosis system is crucial to its upkeep and maintenance – for multiple reasons!
But is there a specific length of time for it to be adequately purged?
Let’s take a look.
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Key Takeaways
- A reverse osmosis system’s purging time will depend on several factors. Some purging durations may be up to 24 hours, while some manufacturers recommend purging for 2-3 tank refills, which can take less time.
How Long to Purge a Reverse Osmosis System
So, how long should you purge a reverse osmosis system?
Sometimes, purging an RO system needs to be done for 24 hours. Wondering why it’s necessary to purge it for a full day? The purpose of purging is to release water through the RO faucet for an extended period, eliminating any chemicals and other contaminants or debris trapped in the system. The slow filtration rate of RO systems plays a role. It usually takes around 2 to 4 hours for an average under sink RO system to fill a storage tank, which means flushing the entire system can be a longer process than expected.
For certain situations, a complete 24-hour purge for an RO system may be excessive. It is recommended to refer to the manufacturer’s guidelines when initially setting up the system to determine the appropriate purge duration. Typically, when replacing the RO membrane or sanitizing the system, the process can be simplified by filling and discarding between one and three tanks, which usually takes less than 24 hours. The time required for filling and discarding a single tank depends on the water tank’s capacity and ranges from 2-4 hours. Smaller tanks may require a shorter time.
One way to determine the adequate purging duration after cleaning your RO system with bleach is by checking for the absence of bleach odor. Cease purging only when the smell of bleach can no longer be detected.
How Often/When to Purge
Your RO system should be purged twice a year, as a general rule. But there are some specific circumstances in which purging afterward is absolutely necessary.
Newly Installed RO System
When you install a brand-new reverse osmosis system, manufacturing debris may be present, as well as carbon dust and filter preservatives. Purging the system eliminates these and also primes the filter elements for use.
To initiate the system flush, open the RO faucet and allow the water to trickle out for the recommended length of time. Avoid consuming the water during this process. Various manufacturers propose different approaches, such as a 24-hour flush or filling and discarding the tank 1 to 3 times.
Fresh Reverse Osmosis Membrane
Reverse osmosis membranes often have residual preservative chemicals on them, so when a new one is fitted, the system should be purged to eliminate these. This would happen each time the RO membrane is replaced, so between 2-5 years.
Aside from the membrane, other filter stage likely need priming/purging as well!
After Sanitization
RO systems should be sanitized every 6 to 12 months to eliminate microbial contamination. Once the sanitization process is complete, flush the system thoroughly to ensure no cleaning agents like bleach are left there to be consumed. If the tank is connected during sanitization, it should be filled and flushed to remove any remaining chemicals. The system is purged when the water no longer retains any chemical taste or odor.
Further Reading:
Instructions for Purging a Reverse Osmosis System
Here’s a how-to for purging your RO system:
- Start by turning on the water supply to your reverse osmosis system.
- Next, open the reverse osmosis faucet to allow water to flow through the system for the recommended duration.
- Once the recommended time has passed, close the RO faucet.
If you also need to flush the storage tank, allow it to fill 1 to 3 times. Empty after each round of filling.
If you have any questions about how long to purge an RO system please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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