Water purification technology has come a long way, but many groups (particularly the environmental ones) think it still has a long way to go. Most of the methods of water purification that are in use today have been around for many years. Some were developed before the turn of the century. One was even used in Ancient Babylonia.

Distillation was the first attempt at water purification technology, even though the systems were not originally designed for that purpose. The concern of the ancients was not removing contaminants from the water supply. Water-borne illnesses were around, but no one knew what bacteria were. They used distillers for alcohol.

Distillation methods of water purification are good for certain purposes, but for drinking, there is concern about stomach problems, because there is a lack of minerals and an unhealthy pH level. Certain contaminants with a low boiling point are not removed through this process, only vaporized.

Reverse osmosis was considered a big step forward in water purification technology, but it's really not much better than distilling. It just costs more. It is one of the methods of water purification used by treatment facilities, along with a multitude of other steps. There are a number of industrial applications. The removal of minerals prevents early equipment corrosion.

The biggest advantage of reverse osmosis methods of water purification is in the area of desalination or removing salt from sea-water. Additional steps, including re-mineralization, must be used to make the resultant drinkable, but without RO, it wouldn't be drinkable at all. It's too expensive and wasteful for most homes and it doesn't remove the chemical contaminants that concern most of us.

Because the treatment facilities can only do so much, the majority of today's water purification technology has been developed for "point-of-use" or in the homes. Pitcher filters are the least expensive. They can remove chlorine, lead and improve the taste and smell. The tiny filtration unit has a short life span, so even though initially inexpensive, the cost per day is higher than in other devices.

Multi-media block and activated carbon filters are often referred to as the best water purification technology available, because nearly every contaminant can be removed by them, including dangerous by-products of chlorination disinfection.

Multi-media blocks are one of the few methods of water purification that can remove microscopic "cysts". Those tiny creatures float into the system at various points, are nearly impossible to detect and cannot be removed by most treatment methods. If ingested, they can infect the intestines causing severe illness and even death. Those at highest risk are the very young, the elderly and people with existing health problems, because of an already weakened immune system. Most of use would think we had food poisoning or the stomach flu, because the symptoms are similar and we'd be able to fight it off in a few days.

Multi media methods of water purification can also be used to balance mineral content and pH levels. The better home systems make use of this highly advanced water purification technology.

Multi stage systems are the most effective and yet they are one of the most affordable.