How to Maintain Your Reverse Osmosis System
How to Maintain Your Reverse Osmosis System

How to Maintain Your Reverse Osmosis System

Whether you've got a brand new reverse osmosis system or you just moved into a house that had one previously installed, you probably want to understand the basics of a reverse osmosis filter maintenance to ensure that your water remains as pure as possible. Here are three basic ways to keep your system performing for many years to come:

Drain the Storage Tank

NU Aqua Reverse Osmosis System under sink

Ideally, you should completely drain your storage tank about every two weeks, especially if you don't use very much water at a time. A good time to do this might be right before bed, or before you leave for work, so the tank has plenty of time to refill before you want to draw on it again.

Why drain the tank? Using just a little bit of water at a time only removes and replaces the water at the very top of the tank. Completely draining your tank not only ensures that the water in your tank remains fresh, but a larger draw helps the reverse osmosis membrane maintain the pressure it needs to fully reject impurities.

Note sure what you do with the excess water? Consider using that drained water to refresh potted or garden plants—they'll appreciate the drink, and your system will thank you, too! That water also has no impurities in it, so it’s also good for cleaning, too.

Replace Filters Regularly

While a well-maintained system can last up to seven years before the reverse osmosis membrane needs replaced, not replacing the pre-filters could result in early membrane failure. The reverse osmosis membrane is very sensitive to chlorine, which will degrade and ruin it without routine maintenance. That's why the pre-filters are so important. The sediment filter spares the carbon-based pre-filter from getting overly clogged too soon, while the carbon pulls out chlorine that will damage the membrane. As you can see, these filters play off one another, so it’s important to keep an eye on each of them and replace them as needed.

Sediment Filter:

Depending on your water source and the amount of sediment going into the system, you should change your sediment filter every 6 months to 1 year. Protecting the other filters from sediment buildup will improve their performance and overall longevity.

Carbon Pre-Filter:

Complete set of reverse osmosis filter

Regularly changing the carbon pre-filter is especially important if you have municipal water that is highly chlorinated. The carbon traps and removes chlorine, which would quickly degrade your reverse osmosis membrane, so change it every six months for highly chlorinated water, and yearly otherwise.

RO Membrane:

If you have softened water and maintain regular pre-filter maintenance, your reverse osmosis membrane could last as long as 7 years. However, if you have hard water, it will be rougher on the entire system and the membrane may only last 2-4 years. A reverse osmosis system will last longer if the water flowing through it is softened. Since osmosis easily removes salt, this will result in the same clean, pure water, but without stressing your filters with hard water as a source.

Post Filters:

When it comes to the post-filter -- which only polishes pre-cleaned water from the storage tank -- you should only need to be replaced once per year, with minimal loss of quality. Unlike the other filters, it doesn’t do as much work, so a yearly replacement should be sufficient in all circumstances.

A final note on filter changes:

Not only will regular filter replacement extend the life of your system, but it will also keep your water flow rate from decreasing. Once the filters become clogged and the entire system becomes noticeably sluggish, that’s a sure sign that you need to replace the filters. If your system regularly becomes slow before your annual maintenance is due, you may have to adjust your schedule to compensate for poor incoming water quality or other factors decreasing the efficiency of your system.

Sanitize Your System

Visualization of inside of reverse osmosis membrane

Every time you replace the RO membrane, you should sanitize your system. All water storage tanks will eventually grow slime when left unchecked, and regular sanitation is necessary to remove it and prevent buildup.

You should perform this sanitation once a year, even if you’re not replacing the membrane. You can do this when you perform your yearly filter changes, since you’ll need to remove the filters anyway in order to cleanse the system.

Follow these ten easy steps to cleanse your system and you’ll prevent the buildup of unwanted biofilm, or slime in your storage tank:

  • Turn off water input by shutting it off at the source valve.
  • Turn on your RO faucet until the tank is completely drained.
  • Open all filter housings and remove the filters and RO membrane.
  • Place about one cup of hydrogen peroxide into the stage one filter housing.
  • Keeping the filters out of the housings, replace the housing covers.
  • Re-attach all connections tightly, making sure there are no leaks
  • Turn the water input valve back on
  • Allow the storage tank to fill which it will do quickly without having to go through the filters
  • Run the system through at least two full cycles
  • Turn off the water, drain the system, install your new filters, and run it through one more fill/drain cycle. That’s it! Your system is now ready to purify your water once again!

With proper maintenance and regular sanitation and filter replacement, your reverse osmosis system will serve you faithfully for many years.