Types of Water Filters
Over the next decade or so, as the general public learns more about the health consequences of drinking and showering in contaminated water, water purifiers will become standard home appliances. Since you're already shopping for a home water filter, you're ahead of the curve - and it's a good thing! We have over 75,000 toxic chemicals in our environment, and approximately 1,000 new toxins are introduced every year. These harmful chemicals end up in our water and in our bodies, where they wear down the immune system, paving the way for disease.
Because of growing awareness about the universal contamination of tap water, the bottled water industry became a giant in the past 15 years. Now, finally, people are beginning to realize that most bottled water is no better than tap water. In fact, much bottled water is even more contaminated that tap water. Plastic water bottles not only pollute the environment, but they also pollute our bodies with hormone-disrupting chemicals.
The only sensible solution to the problem of water contamination is to invest in a home water filter. Instead of paying $1.00 a bottle for contaminated water, you'll be paying just 10 cents a gallon for the cleanest water available.
Fortunately, once you get past all the marketing hype, it's relatively easy to choose the best water filter for your needs. You want to buy the filter that produces the best water quality at the best price. When you're shopping for a water purifier, compare contaminant reduction capabilities, system cost, and ongoing cost per gallon, and the best choice will soon become obvious. See Compare Water Filters for a comparison for popular brands.
Now, let's review the most popular water purification technologies on the market today:
Water Distillation
Water distillers come in many varieties and produce pure water through distillation, which involves boiling the water to produce steam, leaving solid contaminants behind. The steam then condenses back to a liquid form.
While water distillers produce fairly pure water, they also filter out healthy minerals like calcium and magnesium. Additionally, distillation is not very effective at removing organic compounds since they typically vaporize at a lower temperature than water and are transferred in the steam. For this reason, a distiller should always be used in conjunction with a carbon filter.
Water distillers produce water at a very slow rate, and the process costs upwards of 20 cents per gallon. They also leave behind a mineral scale, which means that distillers must be cleaned frequently.
Reverse Osmosis
Before we examine reverse osmosis, let's look at osmosis. Osmosis is a physical process in which water diffuses across a membrane (such as a cell wall membrane) from a solution of low solute concentration to a solution with high solute concentration. The "solute" is the non-water component of the solution. Water, as a central force of life on our planet, strives to keep things balanced.
Reverse osmosis uses pressure to force water across a membrane, leaving all of the "solutes" (contaminants) behind. Reverse osmosis forces water through a semi-permeable membrane, which leaves the solute behind but allows the solvent (water) to pass through.
However, some synthetic minerals like herbicides and pesticides are smaller than the openings in the R.O. membrane; for this reason, a reverse osmosis filter should be used only in conjunction with a carbon filter. Reverse osmosis system typically waste two to three gallons of water for every gallon that they purify and cost upwards of 20 cents per gallon to operate.
From a health perspective, the main problem with reverse osmosis is that, like distillation, it filters out natural minerals as well as contaminants. In this sense, water that is filtered by reverse osmosis is identical to water filtered by distillation.
Natural water, of course, contains trace minerals, and several studies suggest that natural water is healthier than de-mineralized water. If you only drink water from a distiller or reverse osmosis filter, then you're missing out on vital minerals if you don't acquire them from other sources.
Dr. Zolton Rona, author of The Joy of Health, points out that "the longer one consumes distilled water, the more likely the development of mineral deficiencies and an acid state. Dr. Paavo Airola, auther of How to Get Well, concurs that "long-term consumption of distilled water eventually results in multiple mineral deficiencies."
Furthermore, de-mineralized water is more acidic than natural water, and when our body's fluids become more acidic than alkaline, our body produces more free radicals, which increases the risk of cancer. In fact, many studies suggest that cancer can only grow in an acidic environment.
For these reasons, we offer a reverse osmosis filter with mineralizer, which adds natural minerals back to the water after the reverse osmosis filtration.
Pitcher Filters
Pitcher filters represent a low-cost, healthier alternative to tap water and bottled water. The initial cost is low, but many pitcher filters require frequent cartridge replacements, and this can be expensive over time. Our pitcher water filters last twice as long as store-bought filters. Additionally, pitcher filters have a low capacity (you can only filter one pitcher at a time), and they're not nearly as effective as countertop filters or under sink filters.
Carbon Water Filters
Activated carbon is used in air filters and respirator masks as well as water filters. It removes contaminants through the process of adsorption (yes, that's a "d" and not a "b"), in which contaminants bond to the surface of the filter. When used as the core of a multi-stage filtration process, carbon filters produce the highest quality of water available.
For example, the Aquasana AQ4000 water filter utilizes two different carbon filters to produce five stages of filtration:
Stage 1: The "A" cartridge removes sediment and tiny dirt particles that could clog the pores of the filter.
Stage 2: The "A" cartridge then removes chlorine, the most concentrated contaminant in most water supplies.
Stage 3: The "B" cartridge removes lead through a complex ion exchange process in which lead ions are replaced with potassium ions. This is the most effective method of removing lead from water, and it also enhances the pH balance of water.
Stage 4: After the larger contaminants have been eliminated, the "B" cartridge removes synthetic chemicals like herbicides, pesticides, pharmaceuticals, industrial solvents, and other organic chemical compounds.
Stage 5: In the final stage, a sub-micron filter removes waterborne parasites like cryptosporidium and giardia.
Shower Water Filters
See our Shower Filter Buying Guide for an explanation of the different types of shower filters.
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