Things To Consider About RO Water Filters

Reverse osmosis is at the heart of many home drinking water systems, and its popularity is not coincidental: Reverse osmosis water filtration systems have excellent contaminant rejection characteristics, which makes them one of the most efficient filters on the market.

Thanks to their multi-stage design, these systems are capable of removing fluoride, heavy metals, bacteria, viruses, sodium, chloride, cyanide, and many other taste-altering and health-related contaminants.

Reverse osmosis water filters sound like a great choice for home water treatment, but before you take it upon yourself to install one in your home, there are a few things you should think about first.


“Hungry Water”

Because reverse osmosis systems are designed with excellent contaminant rejection capacity in mind, these filters remove not only dangerous contaminants, but also harmless and often healthy water ingredients like calcium, magnesium or zinc. This will often leave your water tasting bland, and it becomes necessary to reintroduce these minerals into the water.

This is why you’ll see many reverse osmosis systems equipped with alkaline re-mineralizer filters, which add trace amounts of minerals to water and stabilise pH levels. Therefore, if you’re ever faced with the question of buying a reverse osmosis filter with an alkaline filter or one without, we recommend choosing the one that comes with an alkaline or re-mineralizer filter.


Water Usage

Not only that they produce “hungry water”, but reverse osmosis water filter systems are also hungry for water. Water waste is one of the most often criticised aspects of reverse osmosis filters.

Reverse osmosis filters create reject water, which carries contaminants removed from the feed water to the drain, transporting waste products away from the reverse osmosis membrane. If these contaminants are not transported away from the membrane, contaminants will build up and clog the membrane, thus shutting down the entire system.

But, just how wasteful are RO systems? On average, RO systems are considered about 25% efficient. This means that for every 2 litres of RO water, around 8 litres of water goes to drain.

Granted that’s a lot of reject water, but luckily manufacturers have made RO systems more efficient by adding more RO membranes (a process called “staging”, which uses reject water from the first membrane to feed the second membrane, and so on), however, water waste cannot be completely eliminated.

The best you can do to minimize water waste is to collect the reject water and re-use it for other purposes in your household such as watering plants, flushing the toilet, washing your car, etc.

To be fair, an RO filter would not be the most wasteful thing in your household. If you think about the efficiency of an RO system compared to a dishwasher or a washing machine, which essentially waste 100% of water they use, a reverse osmosis filter is actually the least wasteful of these. Not to mention that reject water from an RO system can be reused for various household activities without further treatment, as opposed to water that’s pushed down the drain by a washing machine.

Another argument in the defense of RO water filtration is that these systems serve a more important purpose than dishwashers or washing machines, which is to ensure the safety and cleanliness of your drinking water. So, if you’re not worried about wasting water on the cleanliness of your clothes, why would the cleanliness of your drinking water be less important?


Water Pressure

Reverse osmosis systems thrive on water pressure. Without adequate feed water pressure, your RO system will perform poorly, and possibly malfunction. This is why you should always check water pressure requirements and see it your incoming water pressure meets these requirements.

In some cases, optimal water pressure requirements can be achieved with a reverse osmosis booster pump. This is why reverse osmosis systems come in pumped (feature a booster pump) and non-pumped versions (without booster pump).

Unfortunately, if your water pressure cannot be brought to the required levels not even with a booster pump, a reverse osmosis system may not be a good fit for you, and you should look into systems that are not as dependent on water pressure as RO systems are.

Examples of filters that are suitable for low-pressure environments are inline water filters, which are installed directly on the mains water line, filtering all the cold water that goes through to your tap. Alternatively, you could consider gravity water filters, which are not dependent at all on water pressure, nor do they have to be installed on a source of feed water.


Maintenance & Filter Replacement Costs

Filter replacement is inherent to any water filter system, after all the brunt of the work is carried out by these filter cartridges and their replacement is necessary to ensure the proper functioning of your water filter unit.

However, since ro filters are multi-stage, there are more filters to replaces, which is often costlier than replacing a single cartridge. Not only that there are more filter cartridges to replace in a system, but certain sets are replaced at different intervals than other sets.

For example, in a typical 6-stage reverse osmosis system like the Ecosoft 6-Stage Non-Pumped Reverse Osmosis System with Alkaline Filter, pre-filters are to be replaced every 3 to 6 months, the reverse membrane is to be replaced every 18 to 24 months, and post-filters are to be replaced every 6 to 12 months.

There are, however, ro filters like the BMB-10 +Alkaline +Detox Non-Pumped Quick Change 6 Stage Reverse Osmosis System, which have filter cartridges that are all replaceable at the same time, which in the case of the BMB filter is every 12 months.

You can buy most replacement filters for multi-stage units in bundles or packs, which either consist of all the filters necessary for the annual maintenance of these systems or the 6-monthly maintenance of these systems.

Replacing multiple filters at different intervals is an issue common to all multi-stage systems, not only reverse osmosis systems.



Reverse osmosis water purification systems have some drawbacks, however, their contaminant removal efficiency is undisputed. If you’re struggling with health-endangering contaminants in your drinking water, a reverse osmosis filtration system is your best line of defense against these contaminants.


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