With whole house water purification the goal is to take all of the water coming into your home and filter it before you use it. The filter system is installed on the incoming cold water line as soon as possible after it enters the home. All of the water past that point will be filtered water, so, the whole home has good safe water, even for the laundry and the dishwasher. This article will look at what these systems filter out and how they do it, so you will know the best technology to solve your water problems.
1. Any good home water purifier should do what?
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.
When it comes to removing the harmful chemicals compounds nothing is better at the job than activated charcoal. The Environmental Protection Agency has long recognized activated carbon as the best technology for removing the chemical bad guys, so, a carbon filter is likely to be next.
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.
The distillation process works by heating water until steam forms and that steam is moved to a separate chamber to cool and return to a liquid state. During the process bacteria is killed and inorganic compounds such as lead, potassium, calcium, etc are removed. The process cannot handle organic chemicals very well so distillation must be used together with carbon filtration.
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.
In the process of using reverse osmosis, water is pressed against a semi-permeable membrane about as thick as a piece of cellophane. This membrane will only allow objects the size of a water molecule or smaller to pass through. Even much of the water is rejected along with all minerals in the water and other contaminants. Organic chemicals will not be filtered because of their small molecular size, so, a carbon filter must always be used.
Most reverse osmosis systems produce only a gallon or two of filtered water an hour and will waste two or three times that for every gallon produced. They require a storage tank to create any volume of filtered water and, sometimes, a booster pump as well to maintain pressure. Initial costs for the various components and maintenance costs make these units about equal in cost with distillation.
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.
Selective filtration is it not designed to handle salty water, but, since most of the nation does not suffer from that problem, it’s usually not a big issue.
Selective filtration does not require any electricity and, since the system operates quickly, they don’t need storage tanks either. Also, they barely impede the water flow so no booster pumps are needed. Another big factor is they cost less to purchase and operate than either of the other two systems.
3. Which system will work best 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.