There is a lot of hype and doubtful claims about water filters in the media. It's hard for the average consumer to understand the different methods and types of water filtration systems without buying into all the sales talk.
Water filtration or treatment in itself is a quite a large topic with many methods and technologies involved. Most household water filters/treatment systems are designed to remove various contaminants such as chlorine, lead, mercury, Volatile Organic Chemicals (VOCs), Total Dissolved Solids (TDSs), Cryptosporidium, Chloramines, pesticides, herbicides, Giardia and other bad smell or taste elements.
Feature and Function Differences
Most water filters work on the same general process. Water is passed through a filtration agent (physical, chemical or ultra-violet) where contaminants are either removed or neutralized. The treated water is then either dispensed out of the system or is stored in a storage tank for future use. Generally, most water filters are fairly simple and inexpensive items that aren't very different from one manufacturer to the next. Below is a list of features and functions which you should consider before buying a water filtration system.
1). Filtering Technology
The first and most common sort of filter uses a physical barrier to remove suspended particles such as mud, silt, sand or rust as well as micro-organisms such as Giardia or Cryptosporidium. Physical filters are measured by microns. The finer the filter the smaller the micron number and the more types of particles can be removed from the raw water.
Another type of filter uses chemical processes to remove or neutralize potentially harmful contaminants in raw water. Depending on the type of contaminant, the filter elements can comprise of activated charcoal, copper, zinc etc.
The newest form of filtration technology is to use ultra-violet light to destroy bacteria, viruses or pathogens in water. The ultra-violet light is typically encased in a tank where-by the water is treated either when in storage or is run through a ultra-violet canister. The ultra-violet light deactivated the DNA of the organic particulates which ruin their ability to reproduce and cause disease.
Typically, a water filtration system will contain more than one type of filter because each filter has its own specific strengths and together enable a much wider spectrum of filtration.
2). System Types
There are a few basic types of water filters that range from small portable units to units that can supply an entire house or office. Here are the more common types:
Counter-top: These types of filters are placed on top as of the counter as suggested by the name and is connected to the faucet. The system normally has limited capacity while the filtered water is only available at the faucet.
Under-counter: These systems are very similar to the counter-top systems in that they have smaller capacities and only provide treated water to one faucet. The difference is that these systems don't take up valuable counter space however would require more sophisticated plumbing which makes it slightly more expensive.
Faucet Mounted: These systems are the cheapest and easies to install however offer the least amount of filtration. The system is mounted on the faucet itself and offers treated water to that faucet alone.
Whole House: These water filter systems are typically the most comprehensive and costly filter types that will be needed for a house or office. These systems attach to the pipe mains before entering the house/office which means that they will supply treated water to the entire house/office. These water filters are generally quite expensive to buy and maintain however all water in the house is treated.
Water Softeners: These types of water filters are used specifically to remove only some types of contaminants, namely unwanted elements such as calcium, magnesium, lime, and iron from a household's water supply. These elements make water taste metallic and salty.
Dispensers/Pitcher Water Filter: These systems are normally very simple filter assemblies that are built into a Pitcher/Dispenser. Again, this type of filter is very simple and cheap however doesn't filter contaminants all that well compared to the more comprehensive examples.
Portable: These water filters are made to be portable, some are designed for camping and light travel while some are built into sports drink bottles. Interestingly, an ultra-violet light pen is available which should act as a microbe de-activator similar to more complex household systems as mentioned earlier.
3). Capacity
There are generally two measurements for water filters that use "capacity". Capacity can be used as a measure to determine how much water the filter can actually treat before it needs filter replacements.
On the other hand, capacity is also a measure of the storage tank if the water treatment system is built with a storage tank. This goes hand-in-hand with the flow rate. This measurement is normally in gallons per minute. It should be noted that for counter-top or under-sink applications, flow rate isn't that important as waiting a few seconds longer to fill a glass of water won't be much of an issue. However, flow-rate is very important for Whole House systems, you won't want to be stuck in the shower with no water.
It should be noted that capacity and flow rates are directly related to how expensive the system will be.
4). Costs
When choosing to buy a water filter, you must also consider the maintenance and running costs of the filter. Generally the more complex and higher capacity systems will cost more to maintain and also more to run. Depending on the amount of water treated, water filter systems will need their filters replaced or treated every so often.
Additionally, some complex filters like Reverse Osmosis water filters will only produce 1 gallon of water for every 4 gallons of water supplied which will mean an increase in your water bills too. Further to this, ultra-violet light systems will also require a power source which will also affect your electricity bills.
In conclusion, I hope I have shed some light on buying water filters. The list of points in this article are by no means exhaustive but should serve as a rough guide in the selection process.
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