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How Important is Reverse Osmosis for Drinking Water Filtration?

Avatar for Jodie Weston Jodie Weston  |  Updated: June 12, 2018
How Important is Reverse Osmosis for Drinking Water Filtration?

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In a previous blog, we discussed the benefits of a mechanical filtration system for prepping and in that blog, we began a conversation about Reverse Osmosis (RO) filters. In this blog, we dig a little deeper into the role that RO filter systems can play in the prepping community.

What is Reverse Osmosis?

Osmosis is a natural process where dissolved molecules are able to pass through a shield, such as a cell membrane, from a solution that is less concentrated into one that is more concentrated. In simpler terms, this is a tool that nature uses to equalize consistencies so similar liquids.

water pouring liquid

If you were to take a divided contain and in one half put a cup of water with two tablespoons of salt in it and in the other size a cup of water with ½ cup of salt in it, stir until all the salt is dissolved, osmosis would over time, make both sides of the container nearly equal in salt content, provide that the barrier between the two parts of water was permeable.

Reverse osmosis is just the opposite. It takes drinking water with a lot of dissolved impurities and it forces the water through a membrane that traps MOST of the ions in the water. In nature, Osmosis is a natural process. In an RO filter system, the process is “forced.” RO Systems use increased water pressure to push the water through the special filter membrane. The result is water that is generally purer. I use the word “generally” because an RO filter does not remove ALL types of impurities.

So, why reverse osmosis and not natural osmosis? Natural osmosis is slow and works well for smaller containers such as cells in our body.

What Does RO Filter out of Drinking Water?

First, understand that the quality of a RO system is only as good as its filter. A good filter will remove metals such as lead, chlorides, arsenic, mercury, copper, and many, many others. They can also remove particulate matter such as those elements that do not dissolve in water – Asbestos and biota such as cysts from protozoa and other water “germs.” RO filters also remove many pesticides and even radioactive particles such as uranium.

water glass pouring drink

While RO Filters sound like the perfect answer to clean drinking water, they have their flaws. There is a whole list of chemicals, solvents, and volatile organic chemicals that an RO Filter will not remove. On that list are certain types of pesticides. It is important to understand that there is no single answer to making water pure. That process is highly dependent on what is in the original water source, the RO Filter, and the conditions under which you are trying to purify water.

How Does an RO Filter System Work?

The key to RO systems is the semi-permeable membrane. The process is very much like dividing a single source of water into two parts – the salted side, and the cleaner side. Salts are any material that dissolve in water. So, fresh water from your well is considered salted.

It does not mean that the water tastes salty or that it has sodium chloride in it. It simply means that there are dissolved “matter” in the water. Once the water passes through the filter most or many of those salts are removed and the water is cleaner. It is not pure – just oxygen and hydrogen.

A RO filter uses a few parts. The center of the filter is its semi-permeable filter. There is also a pump, and a waste collection system. When RO Systems work at peak efficiency, they filter up to 99 percent of impurities from the water. Many RO filter systems also have a charcoal sub filter that also helps to remove chemicals as larger particulates before they reach the membrane.

water bubbles liquid

The filter works by using a pump that increases the pressure of incoming water so that it is forced against the semi-permeable membrane. As the pressure increases, water is forced through the membrane and larger ions are trapped and then flushed away as the backflow is discarded through rejection stream.

This system divides your incoming water into two parts – That which is rejected and that which passes through the membrane. The result is the rejection of a high percentage of impurities and the acceptances of highly filtered water. Filter efficiency depends on they type of filter, the condition of the membrane, and the quality of the incoming water. RO filters tend to hit the 95-99% purifying efficiency rate but only for those elements and particulates that are large enough to be trapped by the filter.

Pros of RO Water Filter System

  1. There is a huge list of contaminates that they remove from water including biological matter, metals, radioactive ions, and toxins – both manmade and those that are naturally occurring.
  2. They are affordable. I easily found several under sink units for under $200.
  3. They are widely available.
  4. There is a range of production – Gallons per day – options available.
  5. They are fairly simply to install with just basic plumbing experience.
  6. Most are adaptable such as adding an inline UV filter, etc.

Cons of RO Water Filter System

  1. They are limited in how many gallons per day by their design. – A problem that is overcome by planning.
  2. They are not 100 percent purifiers as there are some things they do not filter out of drinking water.
  3. They require a power source – A problem that is overcome with planning.
  4. They require maintenance and filter changes.

How Important are RO Filters for Safe Drinking Water?

Realistically, RO filters are a must. They are one of the only filters around that address biological, mechanical, and chemical water filtration. No, they are not 100 percent perfect, but they represent the best solution for home water filtration for their price and the quality of water they produce.

Flint, Michigan and the Lead in Drinking Water

This was/is a situation that really irritates me. Lead poisoning is serious and the people of Flint were victimized by governmental representatives who were trying to save money.

The lead in Flint’s water came from corroded pipes caused by withholding a certain chemical that’s purpose was to prevent the corrosion of pipes due to the other chemicals added to drinking water. That is a lot of chemicals added to drinking water and all in the name of safety. Many of those chemicals and the lead would have been removed by an RO inline home filtration system. That alone is a reason to consider installing one in your home.

water tap faucet

Above we talked briefly about both the pros and cons of home RO filters. The fact that RO filters remove so many impurities from drinking water make them a huge boon to preppers. The example of Flint and the lead in their water brings home the lessons of why it is important to control the quality of the water available.

What is in the water we drink has both a short and long-term impact on our health. Our personal health is one of the most important aspects of survival. If we are not healthy enough to survive then the best planning (Prepping) will not save us. RO water filters are another tool that helps us to improve both our short-term and long-term health.

  • Short Term Health Improvements – Filters Protozoa and cysts that can cause diseases such a Giardia. Giardiasis – which is the disease – is caused by the protozoa giardia. An RO System helps remove these dangers from drinking water.
  • Long-Term health Improvements – By removing many of the chemicals, toxins, and biological impurities in water we gain better health simply because our system is not having to filter those elements itself.

Those basic reasons along justify the small cost for an RO filter system. Add into this the potential threats from civil uprising, domestic and foreign terrorism, natural water control issues, such as bacteria blooms, accidents such as sewer contamination and accidental contamination from pesticide runoff or big rig or train derailment where those vehicles are carrying toxins.

hand water pouring

There is an entire list of “what ifs” that are concerning. Two winters ago, the local lake flooded and when it did it causes every septic system along the lake to infiltrate the water. Those people were required to boil their water for months. In addition to sewage other contaminates such stored diesel also leached into the lake.

This is a community that relies on the water from the lake and underground aquafers for drinking water. A series of severe winter storms – They called them atmospheric rivers – had a significant impact on the quality of drinking water here. Natural disasters such as tornados, hurricanes, and earthquakes are all events that can damage drinking water systems.

Is an RO Water Filtration System needed at your home?

It would be hard to argue that one is not needed. When we talk about the cons, most are overcome by planning. Install a battery backup or solar unit to power the pump that drives the system. Carefully plan how much fresh water your home needs on a daily basis and you can choose a RO system that meets those needs. Chances are you will need more fresh water than you think – so go big.

RO Water filters are an opportunity to positively improve the quality of water you drink today and during a disaster. These are simple to use, fairly easy to install, and they make positive improvements to short and long-term health.



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10 Responses to “How Important is Reverse Osmosis for Drinking Water Filtration?”

  1. It’s good to know that osmosis is natural so reverse osmosis should not be that difficult to do. I don’t think I could set up the system by myself though. Having a professional help me out with it would make it a lot easier.

  2. Water is the essence of life. So, it is very important to have knowledge about its purification and water treatment with the effective tips and techniques. Thanks for providing this wonderful list of blogs. This is going to be very helpful.

  3. You do not need a power source for an under the sink RO system. The water pressure in the line forces the water through the membrane and other filters.

  4. My city uses RO for the city’s water supply. My house is a water testing site. In the front yard is a water testing station. A guy from the city comes by every month to test the water. The city has 42 test sites in a city of 103,000 people.

  5. there is also “Alexapure Pro ” which is like the Berkey, but better, only less advertised 😉

    and I will agree with TexasScout on your need to proofread! LOL

  6. We use RO to filter our water in home brewing beer, the results are a much better tasting beer, we do have to adjust the PH since it comes out a bit on the high side but that could be due to the starting PH of the water we use, we have used filtered water and distilled water but by far the RO water produces a better product.

  7. Great article. I have been around prepping and survival long enough to know that water filtration is a difficult question. There probably is no perfect answer. I appreciate the explanation of reverse osmosis.

  8. “Realistically, RO filters are a must. They are one of the only filters around that address biological, mechanical, and chemical water filtration.”

    I think the good folks at Berkey Filters might disagree with that statement.

    PS: Proofread, proofread, proofread. Many simple mistakes.

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