How to Change Filters on a 5-Stage Reverse Osmosis System
Written by: Gene Fitzgerald // Last Updated: Apr 11, 2023
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Like any RO system, regularly changing the filters on a 5-stage reverse osmosis system is the key to clean, great tasting water.
A 5-stage RO filter is the standard when it comes to home units, with most of these systems coming in one of two basic configurations:
- The first configuration is 1 to 2 sediment pre-filters, 1 carbon pre-filter, the RO membrane, and 1 carbon post-filter.
- The second configuration is 1 sediment pre-filter, 1 block and 1 granular carbon pre-filter, the RO membrane, and 1 carbon polishing filter.
There is also a third configuration which includes a remineralization post-filter, but we won’t cover that in this article.
Let’s take a look at the filter changing process step-by-step.
Contents
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Key Takeaways
Here is how to replace filters on a 5-stage reverse osmosis system:
- Shut off the water supply and storage tank valve.
- Open the RO faucet and drain any remaining water.
- Remove the pre-filter housings and discard of the old filter elements. Cleaning the housings is optional. Making sure that any O-rings are still in good condition, insert new filter cartridges and screw the housings back on.
- Remove the quick-connect tubing from the RO membrane housing. Open the housing, take out the old membrane, and insert a new one before screwing the cap back on and reconnecting the tubing.
- Finally, remove the tubing from the carbon post-filter. Install a new one.
- Turn the water supply back on, open the storage tank valve, and check for leaks. Consider flushing 1-2 full tanks of water before use.
Replacement Schedule: When to Change Your 5-Stage Reverse Osmosis System Filters & Membrane
| Biannual Replacement | Annual Replacement | Every 3 to 5 Years |
|---|---|---|
| Sediment and carbon pre-filters | Sediment and carbon pre-filters | |
| Carbon post-filter | ||
| RO membrane |
Instructions: How to Change 5-Stage Reverse Osmosis Filters
The filter replacement process will differ slightly depending on the make and model of your particular 5-stage RO system, but these instructions will nevertheless apply to most systems.
Getting Ready
The first thing you’ll want to do is thoroughly wash your hands to prevent containing the new filters. Next, turn off the cold-water supply under your sink.
Then close the storage tank valve and open the RO faucet to allow any water left in the system to drain out. When it stops dripping, shut off the faucet.
Place a large bowl or rags underneath the system to collect any water that drips down during the filter changing process.
Further Reading:
Replacing Sediment & Carbon Pre-Filters (Stages 1-3)
Make sure to check the specific instructions included with your RO systems product manual to verify the exact procedure for your filter model.
- Remove the pre-filter housings by rotating them clockwise until they come loose. If too tight to loosen by hand, use a filter wrench or strap.
- Clean the inside of the filter housings with warm water and dish soap. To sanitize the housing use a little unscented bleach and then wash thoroughly afterward.
- Install the new pre-filters inside their housings and then screw them back into place. Sediment filters go first, followed by carbon filters. While you do this, it’s important to make sure the black rubber O-rings are intact and in good condition before screwing them in. You can use a filter wrench or strap to tighten them, but be very careful not to overtighten – as the housings are made from PVC and will snap if you overdo it.
Changing the Reverse Osmosis Membrane (Stage 4)
To change the RO membrane, first complete the steps outlined in the first section. Then do the following:
- Remove the tubing connection from the membrane housing cap. For a quick-connect fitting, push inward on the fitting and then pull out the tubing.
- Remove the cap by rotating it clockwise. If it’s too tight to be hand-loosened, then use a filter wrench or strap wrench to get it loose.
- Remove the old RO membrane from the housing. If it’s difficult to access, a pair of needle nose pliers can come in handy.
- Clean out the inside of the membrane housing with warm water and dish soap. To sanitize the housing, use a little unscented bleach and then rinse thoroughly.
- Slide the new RO membrane into the housing (the side with the 2 rubber O-rings first) and push until it’s in place. When handling the new membrane, it’s a good idea to use gloves to avoid touching it with your bare hands.
- Make sure the membrane is all the way in, and then screw the housing cap back on. Again, you can use a wrench, but be careful not to overtighten.
- Reconnect the tubing connection you disconnected in step 1.
Replacing the Inline Carbon Post-Filter (Stage 5)
The process for changing the inline carbon post-filter is similar to replacing the RO membrane.
- Push in on the quick-connect tubing connection to remove both tubing on the inlet and outlet of the filter.
- Discard of the old filter.
- Install the replacement filter, making sure to check the arrow for the correct installation direction. Reconnect the two quick-connect tubing connections you disconnected in step one. To ensure the connections are secure, pull back on them and check that they don’t come loose.
After completing any of the above filter changes, the next steps are essentially the same.
- Turn the cold-water supply back on.
- Open the RO tank valve.
- Open the RO faucet and let the system flush through for a few minutes.
- Check the system for leaks.
- Close the RO faucet and allow the storage to fill.
- You might need to discard the first 1 or 2 tanks of water before drinking it. Check manufacturer specifications.
Why Should You Change the Filters on Your 5-Stage RO System?
Changing the filters on your 5-stage reverse osmosis water system on time is vital to keeping it operating efficiently. Clogged filters will not only result in poor quality water but they put stress on the overall system and increase wastewater – which means a more expensive water bill.
Failing to change filters on time can also lead to biofilm accumulation in the system and especially the storage tank.
How Much Does a 5-Stage RO Replacement Filter Set Cost?
Most manufacturers offer all 5 filter stages including the RO membrane as a replacement bundle. Generally speaking, you’ll save money when purchasing them bundled rather than purchasing them piecemeal.
The actual cost varies depending on the manufacturer, but you’re generally looking at $75 to $200 for the full set depending on the filter quality.
How Does a 5-Stage Reverse Osmosis System Work?
5-stage reverse osmosis systems work much like any other RO systems. As mentioned previously, there are slight variations in their configurations, but generally, they follow this process.
- Stage 1 is the sediment pre-filter designed to remove large particulate matter like sand, silt, and dirt from clogging up the membrane and other filters.
- Stages 2 & 3 are carbon filters designed to remove chlorine/chloramine from the water before it reaches the membrane. Chlorine will damage the RO membrane, so it has to be removed here. Carbon filters also have the added bonus of removing VOCs and other chemicals as well as improving the water’s taste.
- Stage 4 is the primary reverse osmosis membrane. This is the heart of any RO system and removes a wide array of contaminants including heavy metals, arsenic, fluoride, bacterial and viral contaminants, pesticides, and microplastics.
- Stage 5 is the final post-filter. It’s generally a granular activated carbon filter to remove any leftover odors and tastes and ‘polish’ the water.
If you have any questions about how to replace your 5-stage reverse osmosis filters please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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