The idea behind whole house water purification is to place a filter system on the cold water supply as soon as possible after it enters your home. This way you will have contaminant-free water in your kitchen, the showers, all over, even for the dishwasher and for washing clothes. In this article we will discuss what needs to be removed from your water, how these systems clean it out and what system would be the best for you.

1. What should you expect for a home water purifier?

Simply put, any good whole house water purifier should give you clean, healthy water by removing virtually all (over 99%), of the debris and harmful contaminants from your water. This would include chlorine, THMs or the toxic byproducts of chlorine, SOCs or synthetic organic chemicals, lead, weed killers, insecticides, pesticides, pharmaceutical drugs, etc., the list goes on and on.

2. How are these systems able to get out all of these pollutants?

Before we start I want you to know these are called systems because no single filter can do all the work. There are a series of filters in any system that do the work and they all begin with a pre-filter for removing the large particulate matter that could jam the filters that follow.

Next, will likely be a carbon filter of some type. Activated carbon is recognized by the EPA, Environmental Protection Agency, as being the best available technology for removing chlorine, THMs, and VOCs (volatile organic chemicals).

The third stage of filtering could come from distillation, reverse osmosis, or a system utilizing the adsorption power of activated charcoal, sub-micron filters and ion exchange called selective filtration or multi-stage filtration.

Distillation is a process that passes water over a heated coil to form steam that rises to a cooling tank and condenses back into a liquid. This process kills any remaining bacteria in the water, and it removes inorganic compounds like lead, calcium, potassium, etc. (The process does not remove organic chemicals, so, a distiller must always be used in combination with a carbon filter).

Only three or four gallons a day is produced by these units so you can see they are very slow. Also, the electricity needed makes them have a relatively high energy cost.

Reverse osmosis units push water against a semi-permeable membrane with very fine pores, the size of water molecules. The process rejects certain contaminants, minerals, and even a large part of the water itself. Most SOCs, such as herbicides and pesticides, are smaller, molecularly, than water and will pass through the membrane and will not be filtered out. That is why these systems must be used in combination with a carbon filter.

These units are similar to distillation since they produce only a small quantity of filtered water per day and they waste two or three times what they produce. To create any volume of water they need a special storage tank and often require an added booster pump to create adequate pressure in the system. Cost of the equipments and subsequent operating costs and waste make these units similar to distillation systems in overall costs.

Since both of these systems remove all minerals from the water, including healthy trace minerals the body needs, a problem is created. Water in this condition becomes a little acidic and, after we drink it, it will have a natural tendency to return to a neutral pH. It does that by pulling calcium from our body. For this reason, some medical professionals feel this water is unhealthy to drink.

The third system starts with the adsorptive power of activated charcoal and it is blended with a chemically charged resin to create a very different, but highly effective, filter media.

This mixture is compressed, or extruded, into a solid block of carbon whose core structure contains small, sub micron pores. As water passes through the carbon block, chemicals, drugs, etc. are physically bonded to the activated carbon. Any cysts such as cryptosporidium and giardia are trapped by the tiny pores, as are any remaining inorganic compounds. Finally, the chemical resin forces the ions of heavy metals, such as lead, to break their bonds with water and the resulting compounds can be trapped by the surface of the filter.

Brackish or salty water cannot be handled by selective filtration systems. However, this would only be an issue with about 5 percent of households in the U.S.

For people without salt water issues, there are big pluses to these systems. They filter water rapidly with little resistance to the water flow, so there is no requirement for storage tanks or booster pumps which means lower initial costs and lower operating costs.

3. What is the best technology to use to get the job done for you?

Reverse osmosis is the only way to go if you a fighting a salt water problem. They are not the cheapest systems to own and operate, but they are by far the best solution for brackish water.

But, if you are like most of us on a city water system or a chlorinated well, I think the selective filtration or multi-stage system is the way to go. The initial cost is less, and, since they do their thing almost maintenance free, they operate inexpensively, only requiring periodic filter changes.

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