Water Filters: What Should Be Filtered Out, What Needs to Stay In

Water filtration is a process crucial to ensuring a supply of clean water. Depending on its source, water can contain a variety of toxins, pollutants, and other contaminants that can be harmful if ingested. On the other hand, quality water will contain beneficial compounds, such as electrolytes, that need to remain in it to make it good for us. Therefore, when filtering water, it’s important to remove certain toxins while retaining certain electrolytes in order to create the safest water possible.

Start at the Source

The first step in water filtration is understanding your water source. This will help determine what needs to be filtered out and what needs to stay in. If you’re using tap or lake/river water, chances are there are more toxins present than electrolytes. Filter out any chlorine, lead, arsenic, sediment, or bacteria that may be lurking in these water sources, since these can all cause harm when ingested by humans or animals. Some filters may also remove beneficial minerals like magnesium and calcium from water during the filtration process. These should be added back into the water after filtration.

If you are using well water or spring water, chances are there are more electrolytes in it than toxins. In this case, it’s important to filter out any organic matter, such as sediment or algae, that may have been introduced through run-off from nearby fields and farms, as well as potentially hazardous microorganisms like Giardia Lambia or Cryptosporidium, which can cause severe gastrointestinal distress if ingested. The same goes for rainwater, which often contains pollutants such as nitrates and phosphates. Filtering out these toxins is key to ending up with safe drinking water.

The water filtration methods currently available to consumers are numerous, each offering its relative advantages and disadvantages.

What’s the Method?

One of the most common water filtration methods is activated-carbon filtration. This process uses a granulated form of carbon, which is highly porous and able to absorb water-soluble contaminants such as chlorine, pesticides, herbicides, VOCs, and unpleasant odors. It also helps reduce sediment in water. Activated-carbon filtration is effective at removing many waterborne contaminants, but it does have its limits. It will not remove some heavy metals, such as lead or mercury, from water.

Another popular water filtration method is reverse osmosis (RO). RO works by pushing water through a semipermeable membrane with tiny pores that remove molecules larger than water molecules, as well as other impurities, from the water. This method leaves behind clean water that generally tastes better than what comes from the tap due to the removal of small amounts of dissolved minerals like sodium chloride (salt), which can make tap water taste bitter or salty. Unlike activated carbon filters, however, reverse osmosis systems are not able to remove all bacteria or viruses from water, so they need regular maintenance and may require additional disinfection.

Distillation is another popular type of water filtration. In this process, water is heated until it reaches its boiling point, evaporating as steam, which is cooled and condensed into liquid form, leaving out any solid particles or contaminants present prior to distillation, such as sediment or algae, as well as the dreaded Giardia Lambia or Cryptosporidium mentioned above. 

The downside of distillation is that it requires significantly more energy than other filtration processes, as it involves heating up the entire container of water for several hours, rather than the minutes other methods take, making it more expensive for those looking for quick access to clean drinking water and those who are trying to conserve energy. Certain pollutants, such as volatile organic compounds (VOCs) or heavy metals, may still remain in distilled water. Depending on your individual situation, more advanced filter systems may be required.

What Stays Behind

Overall, determining what needs to be filtered out and what needs to stay in depends heavily on where your drinking water comes from and how much time and money you choose to invest in the process of purifying it. Still, when set up correctly, a good filtration system will provide clean, safe drinking water by removing any potential toxins while still maintaining a balance of beneficial electrolytes, making it perfect as both drinking water or as the starting point for tea, coffee, soup, punch, smoothie, or any other delicious liquid that uses water as its base.