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How Do Water Filters Work?

Whether you believe it or not, humans can only go about two days without water before they die. They can go much longer without food. It makes sense, then, that people want to make sure the water they drink is safe and pure.

You have a few choices. You can trust that the water that comes out of your tap is healthy. It really depends on where you live and what kind of water system your town has. Or, you can buy bottled water and spend hundreds of dollars a year buying bottled water. That’s always an option. Or, finally, you can invest in a water filtration system.

The great thing about water is that it is natural. It flows through creeks and rivers, oceans and bays. It then finds its way into your pipes and into your glass. You have to wonder what water picks up along this journey. Does it pick up dirt and minerals? Yes. Does it pick up chemicals? Yes. So, before you drink it, you want to make sure it is filtered for impurities.

Two Main Types of Filtration

There are two basic ways of filtering water. One way is to strain water to get out debris and impurities. This can be done with any type of sieve. In fact, back in 500 B.C., Hippocrates realized the healing powers of water. He created what was called the “Hippocratic Sleeve.” It was a bag that he used to remove debris and odors from water to make it taste better.

The other way is to purify it chemically. You essentially use one chemical to rid the water of a bunch of other chemicals. The first option sounds like it is safer. Using a chemical to treat water doesn’t sound very safe. However, both methods are safe and both are used every day.

Physical Filtration

Physical filters are designed to remove solid materials from water. This can be physical debris such as leaves or sediment. Or, it can be chemical precipitates that have built up in the water. The filter itself is made of metal, fiberglass or plastic and they are filled with a loose filter media. This filter then stands on a material such as gravel.
A physical filtration system can be either up-flow or down-flow. They can be filled with any number of different filter media. It really depends on what materials you are trying to filter out of the water. Often times, a series of filters are installed to make sure they don’t clog up. It also ensures that multiple filters will catch all sorts of debris and contaminants.

Chemical Water Filters

The other way of filtering water is with chemical filtration. Often, water enters our plumbing systems with a ton of chemicals in them. Some of the chemicals we see in our water resources include:

  • Chlorine
  • Pesticides
  • Industrial solvents
  • Trihalomethanes
  • Polychlorinated biphenyls
  • Halogenated hydrocarbons

This is just a few. There are many more that we are aware of thousands that we’re not aware of.
Municipalities do filter our water enough to make sure it is safe to drink. However, a lot of chemicals still make it through. In fact, chlorine is actually added sometimes in an attempt to purify the water. Fluoride is also added in an effort to help make teeth stronger.

There are two major types of chemical filters:

  • Granular activated carbon filters – This is the most common type of chemical filter and is known as GAC. GAC get rid of many pesticides and chlorine. All GAC are is specially treated carbon that is very porous and will have a large surface area. When chemicals are absorbed into the water, they stick to the GAC and don’t make it through to the water we drink.
  • Catalytic Carbon Filter – There are some chemicals that even a GAC can’t remove. One of these are chloramines. This is a chemical that kills fish and plants. It can also be dangerous to dialysis patients. Chloramines is an alternative used by many towns to purify their water. This type of carbon is able to remove chloramines.

Sometimes, people combine carbon filters with other types of chemical filters depending on what types of chemicals they are trying to remove.

Three Other Types of Water Filtration

Physical and chemical filtration are popular methods of water filtration. They are also the two types that people can understand easily. There are three other types of water filters. They are:

  • Reverse Osmosis – This just means that contaminated water is forced through a filter at a very high level of pressure. The goal is that the water passes through but the contaminants are left behind.
  • Ion Exchange – This method breaks down atoms into ions. It sets aside the contaminated ions and releases less harmful ones instead.
  • Distillation – If you boil water, it will kill off most contaminants. Distillation goes one step further. It boils water and then takes the steam and creates water from it. It then boils this new batch of water to get out even more contaminants. Distillation is the least effective method of water filtration.

Pros and Cons to Water Filtration Systems

As with any product, there are pros and cons to water systems. You must remember though – we are talking about clean water. The cons would really have to outweigh the pros to justify abandoning the notion of water filtration.

Here are some of the pros to water filtration:

  •  Water tastes and smells better – the obvious pro is that the water will taste much better if it’s filtered. Filtration removes a lot of harmful toxins along with physical debris and sediment.
  • Convenient – Water filtration systems filter the water for your entire house. So not only are you drinking clean water, but you are making your ice and cooking with clean water. You are also washing your car and bathing in clean water. Given the types of contaminants in unfiltered water, this should be good news.
  • Can be cost efficient – Having water filters can be cost-effective over the long haul. You save money on bottled water. You are better off with a systematic filtration system as opposed to faucet filters. It is only one item you have to worry about repairing and replacing rather than half a dozen or more faucet filters.
    There are also some cons associated with water filtration. No system is perfect.

Here are some of the cons:

  • You have to purify and filter all the water that comes to your home – This means that you are filtering water that is going to be used to mop the floor, clean the bathroom and wash the dog. It may seem counterproductive. It has to be balanced with the notion of having filtered water for your family.
  • It can be expensive – Yes, a water filtration system can be an expensive initial cost. However, over time, it may be worth the money. You will have to put out the initial money for the system.
  • You may be filtering out helpful chemicals – There are people who are large proponents of fluoride. They believe that it is good for our teeth and bones. However, others are not trusting of any chemicals, especially after the recent incident in Flint, Michigan.

The Verdict

Water filtration systems have been around since 500 B.C. Yes, the first ones were rudimentary at best. However, it shows that people have been concerned with having clean water for thousands of years. It is nothing new. We cannot lay claim to is as a modern concept.

Over the years, water filtration systems have become more sophisticated and more effective. We now have different types of filters. There are mechanisms that can be attached to both an entire water system or just your certain sinks and faucets.

Before you select or install any water filter, check with a local professional. Make sure it is installed by a skilled professional.

Walt Anderson

Walt Anderson

I'm Walt Anderson, a general contractor from Montana. I specialize in water treatment and I have installed water filtration systems, water softeners and water heaters in residential homes for over 20 years. When I'm not working on this site, I'm at my cabin in the backwoods of Montana with my two dogs, Kurt and Russell.

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