How Often do Reverse Osmosis Filters Need to be Replaced?

To ensure that your RO system is running at its peak performance, you need to replace the filters periodically. This will help you get the cleanest and safest water possible for your home.

But then, how often should you replace the RO filters? Most RO systems manufacturers recommend changing pre and post-filters every 12 months on average. This will, however, depend on the volume of water being used and its quality.

In this post, we discuss why you need to replace the filters, signs that your water filters need replacement, and how to change your RO filters.

Signs that Your RO Water Filter Need Replacement

How Often do Reverse Osmosis Filters Need to be Replaced

Although a reverse osmosis water system is powerful, its filters won’t last forever. The units need a little maintenance from time to time to keep them operating as they should.

So, how do you tell it’s time to change the system’s filters?

  • Low Water Pressure

If you’re feeling a little impatient as you refill your glass of water, there’s a problem. Low water pressure indicates that the system’s filter replacement is long overdue.

And although your RO system is never going to be jet-powered, the flow rate needs to be relatively quick.

  • Foul Odor/Taste

RO water is free of metals, minerals, and bacteria that you can find in tap water. Without the contaminants, this water tastes excellent, which is why most people like it so much.

Noticing the taste and smell of chlorine in your water means that it’s high time you replaced the carbon filters in your system.

  • System Always Running

You’ll also know that it’s time to change the filters if your unit sounds like it’s always running. Clean RO filters make for a better system.

  • Indicator Alerts

Some reverse osmosis systems have an indicator alert that lets you know when to replace the filters. Such systems will even shut down after you have used 500 gallons of RO water to ensure that you’re changing the filters often enough.

If you are always busy with work, it’s very easy to forget to change your water filters. A system with an indicator alert comes in handy.

Reasons Why You Need to Replace Reverse Osmosis Filters

Reasons Why You Need to Replace Reverse Osmosis Filters

1. RO Pre-Filter

The reverse osmosis sediment pre-filter’s job is to prevent sand, dirt, and other particles from getting into the system. It’s actually the unit’s first defense against debris that can damage the membrane.

It’s therefore very important to replace it often depending on the level of debris of the incoming water.

2. Carbon Filter

Many RO systems come with a carbon filter whose primary function is to remove chlorine that might be present in the water.

Chlorine is very damaging to an RO system; hence very crucial for you to change the carbon filter from time to time.

The Carbon filter helps to remove unpleasant odors and tastes from your water. Be sure to change it often as part of your filter replacement process.

Key Things to Remember When Replacing Your RO Filters

You should always replace all the filters on your RO system every time, with the exception of the RO membrane.

You also need to sanitize the system once per year or whenever you change the filters.

You should also get a TDS meter(View on Amazon) to help you check the quality of the water entering and coming out of the system. These meters come at affordable prices and are also very easy to use.

You only need the water that feeds the system; fill the TDS meter cup, turn it on and then insert it in the cup to get a reading. Do the same for the water coming out of the unit.

If your RO water reading is 10% or less than the TDS of the incoming water, your membrane should be fine.

How to Change Your RO Filters

Before you begin, ensure that you have the sediment pre-filter, carbon filter, post-filter, and other filters that you’ll be replacing ready.

To sanitize the system, ensure that you have the sanitizer ready and a pair of sterile gloves for handling the sanitizer and the filters.

And if you will be changing the membrane as well, ensure that you don’t touch it with your bare hands to prevent contamination. Oils on your skin can damage the membrane.

Get a clean towel (not too big) as there will be some water (most likely) leftover that you’ll need to dry up when you’re done. A clean bucket will also come in handy.

And now the replacement process…

Different RO systems use different types of filters. However, most of these systems come with removable housing that holds the filters.

To replace the filters in such systems, all you need to do is simply pull out the old filter, clean the housing and replace the old filter with a new filter.

The second most common type of RO systems come with an enclosed housing with filters sealed in. You just need to screw it off and screw the new one on to change the filter.

The 3rd type is a cartridge filter that is usually totally enclosed. To replace the filter, give it a quarter turn and pull it off. Push the new one up, give it a quarter turn and lock it in place.

Checking Your RO Storage Tank After Replacing the Filters

After changing the filters, you need to ensure that you’ll be getting all the water you need from the system’s storage tank.

To do this, check to ascertain that the pressure in the storage tank is correct. If the pressure is too high or low, you won’t be getting all the water out of the system, as you ought to.

By emptying the tank, you can check to ensure that the pressure is at its best for the tank to empty and fill correctly. You can use a low-pressure bicycle tire gauge and a bicycle tire pump to check the pressure.

Frequently Asked Questions

i. How often should you replace an RO membrane?

How often the membrane requires to be replaced varies from system to system and household to household.
For instance, if your house has a TDS count of 100 and you live alone using 1 gallon of RO water per day, the membrane can go for years without replacement.
But if your house has a TDS count of 1,000 and your family uses 30 gallons of RO water per day, you might need to replace the membrane yearly.

ii. How do I tell if my reverse osmosis filter is bad?

You’ll know that your system’s filter is bad if the RO water has an awful taste and odor, if water flows slowly from the faucet and if the system operates with a lot of noise.

iii. What happens if you don’t change RO filters?

Failure to replace RO filters on schedule, the system will begin to produce less water. Over time, it won’t produce water at all.
A decrease in water production indicates that you have reached the end of the filter and membrane life.

iv. Do you need to clean an RO system?

Yes. You need to sanitize the system once per year. You can consult the system’s user manual for directions on how to go about it or seek help from a water treatment professional.

v. How long can an RO system last?

If your service and maintain correctly, it can last for years (10 to 15). Just ensure that you sterilize the system annually and follow the membrane filter schedule.

vi. How will you know that your system’s RO membrane needs replacing?

The best way to know when to replace your RO membrane is by checking the TDS level of the purified water. If the TDS level is high, it means that the water has contaminants, an indication that the membrane isn’t working as it should. It needs replacing.

vii. Is RO water good for the kidneys?

Reverse osmosis filtration removes all inorganic and unhealthy minerals that your body can’t process. Build up of these minerals, especially calcium, leads to problems like kidney stones and gallstones.
And since RO water is devoid of these contaminants, it’s very safe for the kidneys.


Regular filter changes ensure that you always have clean, safe, and healthy drinking water. With proper care and frequent filter replacement, your RO system will last for years to come.

We hope that you now have a clear understanding of how and when to replace the filters.

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