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An under sink reverse osmosis system effectively purifies water for drinking, cooking, and other household uses.
But unless properly maintained, it can become clogged with dirt and mineral buildup, reducing its effectiveness and leading to costly repairs or replacements.
With a few simple steps, you can ensure that your under sink RO system continues to work optimally, giving you access to pure water whenever needed.
So, how do you maintain an under sink reverse osmosis system?
The absolute most crucial thing when maintaining under sink RO filtration systems is to change the filters regularly – no surprise.
The condition of the source water will influence how often the filters need changing. For example, if you have feed water with a lot of sediment, or hard water, it can reduce the lifespan of your pre-filters by quite a lot.
The other thing to consider is how often the RO system is used. If you are using it just for one person’s drinking water, the filters will last longer than for drinking and cooking for an entire family.
Generally speaking, pre-filters need replacing every 6-12 months, while a post-filter could last a couple of years.
The RO membrane can last up to 3-5 years, provided you kept any pre-filters in good condition.
Not keeping up with the maintenance schedule for filter change can result in pathogens being active in your drinking water, a drop in your water pressure, higher wastewater production, and possibly changes to the aesthetics of your water.
|Biannual Tasks||Annual Tasks||Every 3 to 5 Years|
|Replacing pre-filters||Replacing pre-filters|
|Replacing RO membrane|
|Checking storage tank pressure|
Your product manual would contain specific step-by-step instructions for your particular system. The following is a general process that works for most under sink RO models, but remember that they all are slightly different.
This is the first stage filter in your RO system. It removes the bigger bits of sediment so that your RO membrane can focus on filtering out the microscopic contaminants. It also prevents the RO membrane from clogging or fouling.
The sediment pre-filter needs to be changed every 6 to 12 months.
Stage 2 or 3 of your under sink reverse osmosis system will be the carbon pre-filters. Among other contaminants, this removes any chlorine and some other water disinfectants. Chlorine is very damaging to the delicate RO membrane and needs to be removed from the water before it passes through the RO filtration step.
These block or granular carbon pre-filters should be changed every 6 to 12 months.
At the heart of the operation, the RO membrane filters out up to 99.9% of all the other contaminants from your water, leaving almost 100% pure H2O. RO membranes have a longer lifespan than the filters, but only if you replace the pre-filters according to schedule. The best way to determine if your RO membrane is no longer working as it should, is to test for total dissolved solids in the RO water.
Check the manual or with your manufacturer to know exactly when your RO membrane should be replaced.
Carbon post-filters remove any residual tastes and odors that may have come from the water sitting in its storage tank. They should be changed every 12 months, but some can last up to 2 years.
Sanitizing your RO system may be necessary in some cases, such as after a boil water advisory, or if you have not adhered to the filter maintenance schedule. We recommend cleaning it at least yearly just to be on the safe side. To clean and sanitize your system:
Some RO membranes can also be soaked in a chemical solution. Refer to the manufacturer to see what is recommended for yours.
If you don’t have adequate pressure in your RO storage tank, not only is there a possibility of increased wastewater, but you won’t have a sufficient flow rate from your faucet. A pressure gauge will do the trick to check it. When the tank is empty, it should measure at 6-8 psi. If it is less, you can use a bicycle pump to increase it.
While a lot of the time, there may be no sign that the RO system needs maintenance, as many water contaminants leave no taste or smell, there are some things to look out for:
RO water should have almost no taste and no smell. If your water has an unpleasant taste or smell, it is a sign that one or more of the filters may need replacing.
Storage tanks may need to be repressurized.
The storage tank is not triggering that it is full, and it may need to be repressurized, or you may need a new storage tank. A broken valve may also be causing the issue.
RO system maintenance is essential mainly because there may be no sign that your water is contaminated. For one, most viruses and bacteria are invisible to the naked eye and have no taste or smell, so you wouldn’t know if you were drinking something potentially harmful. Staying on track with the maintenance schedule ensures the system is always effectively filtering contaminants from the water.
Another factor is wastewater. An improperly maintained under sink RO unit could waste considerably more water than a system that’s in shape.
If you have forgotten to change the filters, you will need to stop drinking the water, remove and discard the old filters and the RO membrane, flush and sanitize the entire system, and then replace the filtration components with new ones.
You may even consider purchasing a new storage tank, as it cannot be opened to clean inside and may be contaminated.
If you have any questions about under sink reverse osmosis system maintenance please don’t hesitate to leave a comment below!
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