There are so many different water purification filters available, choosing the best one can be daunting. The terms purification and filtration, although often used interchangeably, are not the same. Purification is a chemical process using iodine or chlorine, sometimes in combination with ozone or ultraviolet light. It removes microbiological contaminants such as, Giardia, Cryptosporidium, bacteria and viruses, producing water that is microbiologically safe. Filtration strains water through a fine physical barrier, or uses a chemical or biological process. There are a wide variety of filtration methods designed to remove many types of impurities from sediment to chemicals to microorganisms. To summarize, purified water, although microbiologically safe, may still contain harmful contaminants, while filtrated water which is free of particulates, may not be microbiologically safe. There are several competitive point of use technologies and no one method removals every impurity completely. Many systems use a combination of methods to improve effectiveness, and each one has strengths and weaknesses.
Begin by determining exactly what your needs are. Do you want to improve the quality of the tap water in your whole house, or are you looking for a portable system that can also travel in your RV, on camping trips or overseas? You may want to be able to purify water harvested by rainbarrels or cistern tanks for long term storage, or for use as emergency drinking water. If it is important that the system be able to function during a crisis, such as a power outage, you may want to consider a gravity fed filter.
How many gallons of water per day do you want to filter? Is it sufficient for the system to provide pure drinking water for you and your family, or do you also want to have enough for cooking and bathing? Will you want to store large quantities for emergencies? The most common recommended estimate for survival water is one gallon per day per person for at least one week.
Next, you must find out what contaminants need to be removed. We are seeing frightening news stories about the questionable quality of our drinking water. New information about the dangers posed to our health by chlorine, arsenic, fluoride, and pharmaceuticals in our water appear daily. The easiest way to get accurate information about your tap water is to contact the local water company. They are required to test regularly and are obliged to provide this information to the public. Ask for a full year of test results as water quality can vary according to the seasons. You can also visit the EPA (Environmental Protection Agency) website where you'll find a listing of the standards for contaminants in drinking water. Remember that Federal law does not yet require testing for an assortment of known toxins and carcinogens that independent researchers often find in municipal water.
Over the counter and home tests are also available but their accuracy can be questionable. The same is true of strips which test for individual contaminants that are sold by aquariums and swimming pool supply stores. Some experts advise buying a digital TDS (total dissolved solids) test meter which will give a reading in PPM (parts per million). The problem with this method is that it is a large measure of dissolved minerals in the water such as calcium and magnesium, not unnecessarily levels of contaminants. Still, it may provide some idea of the overall quality of your water. The most accurate information can be obtained by contacting an EPA and ANS / NSF accredited lab and submitting a water sample according to their instructions. The cost, however, may be high.
Finally, price must be considered. The most expensive, elaborate system may not be the best one. There are a number of excellent units that are simple and economic to operate and maintain. Conversely, if you require large quantities of ultra pure water, the cost may be in the thousands. Many systems such as water distillers and most whole house reverse osmosis systems are electric, so energy costs must be added. Systems which use activated charcoal filters require the filters to be replaced at regular intervals to ensure proper functioning. The best way to compare the price of each system is by looking at the cost per gallon of water. Some systems have a higher initial cost but their low cost per gallon makes them more economic over the long term.
Considering the problems with water purity facing us today, the need for a home water filtration system is evident. Now, having assessed your needs, determined the quality of your water, and determined what you can afford to spend, you can examine the various water purification filters and make an informed choice. Nothing provides more peace of mind than knowing you have chosen wisely.