How to Clean and Sanitize a Reverse Osmosis Water Storage Tank
Written by: Gene Fitzgerald // Last Updated: Mar 8, 2023
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Reverse osmosis tanks, like other components of your RO system, require regular cleaning and sanitizing to keep them sterile and bacteria-free. RO storage tanks, in particular, are susceptible to biofilm buildup, which can turn them into incubators for harmful bacteria.
Luckily the cleaning and sterilizing process is not complex, and as long as you complete it on schedule you’ll have no issues with contamination inside your tank.
So, let’s take a closer look at how to clean and sanitize a reverse osmosis tank – so you’ll have clean, filtered water on tap at all times.
Contents
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Key Takeaways
- Reverse osmosis storage tanks, even more so than other RO system components, are prone to bacteria and biofilm buildup if they aren’t cleaned/sanitized regularly.
- The cleaning and sanitizing process is not complex and as long as it’s completed on schedule you’ll have no issues with contamination.
- The basic premise when it comes to cleaning and sanitizing is adding a small amount of sanitizing chemical to the tank, letting it sit, and then flushing out the system (see below for further steps).
How to Clean a Reverse Osmosis Tank
The basic idea when it comes to cleaning and sanitizing an RO tank is adding a small amount of sanitizing chemical directly to the tank and then flushing out the system. Unlike sanitizing the entire system, this can be done without disconnecting and removing the pre-filters and membrane from their housings.
Tools and Supplies You’ll Need
- Unscented household bleach (or hydrogen peroxide, chlorine, or dedicated tank cleaner)
- Funnel or eyedropper
Step by Step Instructions
- Turn off the feed water supply valve to the RO system.
- Open the RO faucet and drain all remaining water left in the system.
- When all the water is drained, close the RO faucet.
- Close the tank valve on top of the storage tank and disconnect the tubing from the rest of the system.
- Add half a teaspoon of bleach (or another cleaner) to the tubing and hold it upright so it can’t leak out.
- Reconnect the tubing to the RO system and open the tank valve on top of the storage tank.
- Turn on the feed water supply and check for leaks.
- Allow the storage tank to fill completely. This can take several hours so be patient.
- Once the tank is filled, allow the solution to sit for at least 30 minutes and up to 2 hours.
- Finally, open the RO faucet and allow the tank to drain. Allow it to refill completely and then discard the second tank as well. At this point, there should be no chemical odor left in the water, but if there is re-fill the tank and discard it once again.
Keep in mind that your post-filter will need to be replaced after this unless you bypass it to avoid the cleaning solution.
How Often Should You Sanitize a Reverse Osmosis Storage Tank?
So, how often do you need to go through the tank cleaning and sanitizing process?
Most manufacturers recommend cleaning a reverse osmosis storage tank 1 to 2 times per year, which is the same interval they recommend cleaning the entire RO system.
Generally, there’s no need to clean and sanitize the tank separately from the rest of the system. However, if your water has a funny smell or taste, and you suspect the issue is coming from the tank, then cleaning it separately makes sense.
A good way to remember to clean your tank (and system) is to do it at the same time you replace the pre-lifters. These normally must be replaced every 6 to 12 months anyway, so cleaning and sanitizing the systems at that point is easy enough to remember.
The exact frequency of cleaning and sanitizing will depend on your feed water quality. Highly contaminated feed water will be harder on the system and require more frequent cleaning/sanitizing than pristine feed water.
Further Reading:
Benefits: Why Even Bother Cleaning an RO Water Tank?
Clean, Healthy Water Free from Bad Taste and Odor
The primary reason for regular cleaning and sanitizing is to keep your drinking water clean and free of foul tastes/odors. While it may seem counterintuitive, RO systems and their tanks can function like magnets to bacteria, so they need to be cleaned and sanitized periodically.
Removal of Biofilm in Tank Which Could Eventually Spread
The pressure tank is particularly prone to biofilm buildup that could spread through the rest of the RO system. Biofilm is a slimy coating of bacterial buildup attached to the inner surface of the storage tank. It allows bacteria to thrive and turns your storage tank from a sterile environment into an incubator for harmful bacteria.
Better Preforming Tank and Longevity
Removing biofilm and bacterial buildup will ensure your RO tank performs efficiently and as intended. It will also remove scale buildup and eliminate any foul odor/taste from the filtered water.
What Will Happen If I Don’t Clean My Tank?
Failing to clean/sanitize your RO storage tank is a guaranteed way to end up with foul-tasting water. You’ll essentially be allowing bacteria and other pathogens to incubate in your tank, and allow biofilm the opportunity to accumulate and grow wild.
Given that RO systems are not exactly cheap, properly maintaining them with regular cleaning/sanitizing is a highly cost-effective maintenance task that shouldn’t be neglected.
If you have any questions about how to clean a reverse osmosis tank please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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