Water filtration systems are used to convert tap water into that which is safe for drinking. Depending on your area, your tap water may contain lead, toxic metal salts, hormones, or pesticides, as well as other microbes. There aer several types of water filtration systems available to meet the needs of every household. The different systems include, but aren't limited to, charcoal water filters, water distillers, ceramic water filters, reverse osmosis and ultraviolet water filters.
Charcoal water filters are available in three kinds: carbon block, activated silver impregnated charcoal and micron rating. Carbon block is the best form of charcoal water filters, but it has a slow flow rate. Activated silver impregnated charcoal adds a bacteria killing ability to the carbon filter. Charcoal water filters with a micron rating of one or below prevents cryptosporidium and giardia from entering the drinking water. The downfall with these water filtration systems is that they don't change the pH of the water, meaning if your water is acidic before filtering, it will be afterward as well.
Water distillers are convenient, as some are the size of coffee pots, meaning they fit well on your kitchen counter. This type of water filter boils the water, removing all impurities, then runs it through a charcoal filter. It is then transferred to a pitcher, where it can be stored in the refrigerator. The downfall to distilled water is that it removes all the minerals that are necessary for your body's immune system and metabolism.
A ceramic water filter is a cartridge that fits on a bench top filter. Some of these water filtration systems have a porous ceramic outer shell with nano-silver built in to remove enough contaminants to make it bacteriologically sterile. The downfall to this filtering system is that it has a slow flow rate and it doesn't remove chemical contaminants.
Reverse osmosis filters pull water through a very small membrane which acts as a filter. It can convert dirty or salty water to pure drinking water. Just like distilled water though, it removes the necessary minerals your body requires to function. The long-term drinking of water that has been ran through a reverse osmosis filter isn't recommended by many doctors.
Ultraviolet radiation systems use a high-frequency light to kill living organisms in the water. This water filtration system isn't used much in the United States, but they are common in hotels of third world countries. This is a highly effective system, but without constant lab analysis, it can't be guaranteed it is always working.