Drinking water systems are everywhere...Does that mean everyone needs them?
The short answer is no. Some people are perfectly fine with rolling the dice and drinking or cooking with contaminants like chlorine, chlorimine, and ammonia. Others love the permeating smell of sulfur. Live fast, die young, leave a good looking corpse, right? Life is an adventure!
However, the vast majority of people would prefer to have the safest water possible. And let's face it - your local municipal water supplier is just doing the bare minimum it needs to in order to pass the EPA's water testing. The EPA, by the way, is perfectly fine with certain levels of Chlorine, Ammonia, Chlorimines, Arsenic, Asbestos, Cyanide, Barium, Lead, radioactive contamination... should I go on? Here's the complete chart, courtesy of the EPA. So now the homeowner has a few options. Let's run them down and analyze them, shall we?
Activated Carbon Water Pitchers (Brita, ZeroWater, Body Glove, etc): These pitchers work by pouring tap water through a small cartridge (usually about 6" long), which typically helps to remove mercury, copper, cadmium, and the chlorine taste of your water. Filters need to be changed out every two months, or every 40 gallons. Inexpensive choice for one or two people, but the length of the cartridge means a lot of water is being filtered through a small area.
Faucet-Mounted Water Filter: This filter is attached to the spigot of the existing faucet and re-routes the water flow through a cartridge filter, reducing contaminants such as lead, asbestos, as well as cryptosporidium and giardia cysts. Also removes the chlorine taste of your water. Downsides would include a small cartridge (typically 7"), slow water flow, and a filter change every three months or every 70 gallons. Also, if your home has a sprayer as part of your faucet this isn't an option.
Under-Sink Water Filter: Now we're getting to serious filtration. These systems include longer filters (often 2 filters working in conjunction with each other), mount underneath the sink, and aid to remove most harmful contaminants in the water. Filters need to be changed every six months or so. Downsides are higher cost, both for the system and the filters.
Reverse Osmosis Water Filtration System: The best, most effective under-sink system available right now. The reverse osmosis (or RO) system operates with a membrane between a pre- and a post- filter. The system pushes high-pressurized tap water through the membrane, which attracts all types of contaminants and "catches" them. The resulting water is virtually pure, healthy drinking water. The pre- and post-filters need to be changed out every six months or so (one year for the membrane). The upshot is the cleanest water available. The downside is higher cost for the system and the filter changes.
So, the obvious question is...what's in your water?