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How Does a Reverse Osmosis Filter System Work?

by Dr. Jonathan Doyle - Updated September 21, 2020
If you're wondering what a reverse osmosis filter system is in terms of your drinking water, Waterdrop is here to provide you with all the information you need.
Given the way our society works and the way in which our civic system is set up, we all need to rely on a finite number of sources for our drinking water. For most people, that involves using water that's provided by the local water utility, and for some that means drinking from a private well. Regardless, one thing that everyone has in common is the fact that most water that comes from our faucets, if not treated, is not very clean and in some cases unhealthy. In certain situations, untreated drinking water can be dangerous if consumed in large quantities.   
Reverse Osmosis Filter System
For people who are aware of these risks with our drinking and cooking water, there seem to be two choices available: (1) move to where there is clean water, which is not only impractical but also increasingly difficult to locate, or (2) clean the water that comes into their homes. One of the emerging strategies for purifying drinking and cooking water in homes is employing what is known as a reverse osmosis filter system. Waterdrop is one of the industry leaders when it comes to providing water filter system solutions for homes and businesses, and below we're going to explain what a reverse osmosis water system is all about.

What is the concept behind a reverse osmosis filter system?

Before getting into the details of your drinking water, it may be helpful to define osmosis. Merriam-Webster defines it as follows:
“movement of a solvent (such as water) through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane”
In nature, this process occurs most often with plant life. When water is in the ground and plant roots absorb it, water passes through the wall of that root, which is the semipermeable membrane. While it does so, the water becomes more concentrated before it's fully absorbed by the plant.
The concept behind a reverse osmosis filer system is just the opposite. Instead of creating more concentrated water, it breaks down that concentration level and provides water with less concentration, or fewer substances along with the pure water. It does so by forcing water through filters and pressurizing it to help eliminate the contaminants that tend to come with tap water from public utilities or private wells. Basically, water comes into the home from the utility, for example, and before it reaches the faucet, it's pressurized and forced through multiple filters before the clean, filtered water is separated from the wastewater that remains with the contaminants. The clean, less concentrated water is then fed to the faucet (in some models) and the wastewater is either discarded in the drain or it's sent back into the water supply for recycling.
This is obviously an extremely simplified explanation of the reverse osmosis filter system, so below we're going to explain the journey a typical glass of drinking water takes from the public utility, to the home, through the water filter system and ultimately into the glass for a drink of clean, safe water.
The first step in reverse osmosis

The first step in reverse osmosis

The first step involved with a reverse osmosis filter system is generally known as prefiltration. Prefiltration is done in order to remove the sediment that's present in public tap water. Substances such as chlorine can clog and damage the reverse osmosis membrane, which the water will reach later in the process, if it's allowed to remain. Therefore, in order to complete the prefiltration process, the tap water is pressurized and passes through both a carbon filter and a sediment filter, thereby lessening the concentration of that water before it proceeds to the next step. Pressurization is necessary in order to “push” the water through.

The reverse osmosis membrane

After the sediment-free water completes the prefiltration process, it moves on to what is known as the reverse osmosis membrane. This step is the critical process involved with any reverse osmosis filter system. The reverse osmosis membrane is designed to remove particles of sediment that are so small that they were able to escape the clutches of the prefiltration process. When this is complete, the water is now pure and properly clean, free of sediment and other materials that can lead to water that isn't as healthy as it should be.

Storage and the postfilter process

From there, the water is typically sent to a storage tank where it will reside until someone turns on the faucet to access clean, safe, drinking and cooking water. When the tank is full, the reverse osmosis filter system powers down to an extent. When someone does turn on the faucet, the water from the tank goes through what is known as the postfilter process, which is in essence the final cleaning and preparation of the water before it's consumed. When the tank begins to empty, the entire process starts once again.

What does a reverse osmosis filter system remove?

A reverse osmosis filter system removes, depending on the product used, approximately 99 percent of sediment and other substances from tap water before it's consumed. The United States Centers for Disease Control and Prevention, or CDC, published an informational page on water filter systems, and according to that page, a reverse osmosis filter system can and often does remove the following from tap water:
  • Sodium
  • Chloride
  • Copper
  • Chromium
  • Lead
In addition, a reverse osmosis filter system can reduce the amounts of the following substances:
  • Arsenic
  • Fluoride
  • Radium
  • Sulfate
  • Calcium
  • Magnesium
  • Potassium
  • Nitrate
  • Phosphorous
In addition, the CDC reports that a reverse osmosis filter system is highly effective when it comes to removing protozoa, bacteria and viruses. However, this system should not be relied upon to filter out all bacteria and viruses.

Why do some reverse osmosis filter systems need a tank?

Generally speaking, a large number of filtration systems on the market will come with a storage tank because many of these systems filter water very slowly. It's not uncommon for the system to require one minute or more to filter and process only three ounces of water. Therefore, a typical 12-ounce glass of water would take four minutes to fill. Most people are not going to wait that long for a glass of water, or even longer to fill a cooking pot. The tank helps provide that clean water faster.
Waterdrop has innovated on this entire system by way of introducing the tankless reverse osmosis filter system. Our systems are not only tankless, but they are fast and offer continuous water flow. For instance, our G2 Reverse Osmosis Water Filtration System will fill a glass in 12 seconds, and it will offer continuous water flow for however long you use the faucet. Our WD-G3-W is also tankless. In general, the less equipment you need to depend on for anything, the better that system usually works, and avoiding the tank helps consumers have continuous access to clean drinking water without having to worry about cleaning or ultimately replacing a tank at some point.
Why do some reverse osmosis filter systems need a tank?

Benefits of a reverse osmosis filter system

Everyone understands that removing contaminants from anything that we consume is going to provide us with several benefits. The fewer the number of impurities we drink, the better our health is likely going to be both now and into the future. There are additional benefits to the reverse osmosis filter system, and we're going to list five of them below:

Environmental benefits

Making use of the water that's available in your home offers certain environmental benefits. That's because providing yourself with access to clean, safe drinking water in this environment helps you avoid doing things like buying water that's sold in plastic bottles, which creates an enormous environmental problem. Not to mention, some studies have shown that bottled water is actually no safer than untreated tap water.

Removing lead is an enormous benefit

We alluded to it above, but perhaps the biggest health benefit with a reverse osmosis filter system is that it removes the lead from your drinking water. Lead is extremely harmful and has been outlawed from being used in substances like house paint because of the dangers it presents. Examples of problems lead can cause include:
  • Nerve damage
  • Anemia
  • Brain tissue damage
  • High blood pressure
  • Heart disease
  • Kidney disease
  • Infertility
In addition, the CDC has stated that children are especially vulnerable to harm from lead exposure.

It removes sodium, too

In addition too lead, sodium is also harmful to people, especially if it's consumed in high amounts over long periods of time. Live Sf concience published a feature from scientists that discussed the health risks osuming too much sodium, and these health problems included increased risks of the following:
  • High blood pressure
  • Stroke
  • Heart failure
  • Osteoporosis
  • Stomach cancer
  • Kidney disease
There is already enough sodium present in many of the foods we eat, so adding even more from our drinking water is not a good idea.

It tastes really good

People who drink water from a reverse osmosis filter system for the first time are often extremely surprised, or even shocked, at how different it tastes compared to the water they've been drinking for most of their lives. That's because they have been mostly drinking water that was filled with different contaminants and substances, and these “ingredients” affect the taste of the water that's being consumed. Pure, substance-free water tastes almost like nothing, but in a pleasant, refreshing way that's quite new and interesting at first.

It benefits your bottom line

Aside from the environmental harm and potential exposure to contaminants related to drinking bottled water as mentioned above, it also costs a lot of money over time. Another alternative to drinking tap water is paying a water delivery service to bring tanks of water to your home or business regularly. This also comes with a cost, and all the while you're still paying for water service to your home or office. A reverse osmosis filter system allows you to avoid those costs and to make use of your tap water, which generally costs much less than these consumer products.

Is it difficult to install a reverse osmosis filter system?

The term, “reverse osmosis filter system” sounds complicated for those who do not have a scientific or biological background. As such, we've heard from consumers over the years who have had questions regarding whether or not they'd be able to properly install such a system in their homes or offices. When these water filter systems first hit the market over a decade ago, they did take some time, work and skill to install and maintain. We have come a long way since then.
For instance, Waterdrop offers reverse water filter systems that can be installed in as little as 30 minutes, and they will begin producing clean, tasty water almost immediately. That ease of installation is partly due to the lack of a tank, but it's also because we've been building these products for years and want to make it as easy as possible for our customers to get their systems up and running as soon as they can.
 Is it difficult to install a reverse osmosis filter system?
In addition, our relatively simple water filter systems are not complicated when it comes to maintenance. All you'll need to do is replace the filter every now and then, and you'll know when it's time to do so with our smart technology indicator. When that time comes, it's as quick and simple as removing the old part and replacing it with its identical replacement. If you can change a lightbulb, you can handle this task as well.

Purify your drinking water today

There is no substitute for clean, safe and delicious drinking water. It improves your mood, your health and your peace of mind knowing that both you and your family are avoiding unnecessary contaminants that can and will present risks to your nutrition levels and ultimately, to your health. The team at Waterdrop is always excited to talk to people about how they can literally improve their lives with a reverse osmosis filter system, so feel free to contact us at any time so that we can answer your questions and get you further down the path towards providing your home with the clean drinking water you deserve.


Contaminants Detected in  Fruitland Water Special Service District

30  Total Contaminants in Your Water

Water Provider

Fruitland Water Special Service District

Population Affected


Water Source

Ground water
Exceeds Guidelines

Others Detected

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