What is THE MOST IMPORTANT WATER TREATMENT METHOD? Some people will guess that it is water softening or reverse osmosis, maybe ozonation or ultraviolet, but the fact of the matter is that the most important water treatment method is amazingly simple and woefully under-applied or misapplied. That method is simple filtration, which is commonly known as the mechanical or physical operation used for the separation of solids from fluids (liquids or gases) by interposing a medium through which only the fluid can pass. Filtration has been around for thousands of years, and by now you would think that such a simple technology would be properly applied... but it is still not well understood. I'd like to take a little time to explain what works and what doesn't work, and why, when it comes to filtration. First of all, let's break filtration down into two types: (1) Point-of-entry filtration (that means your whole house); and (2) Point-of-use filtration which would be a sink or a fridge. Point-of-Use Filtration (POU) is usually for a kitchen sink or maybe a refrigerator and typically utilizes a 5 micron filter for sediment pre-filtration. Sediment depth filters are generally made of spun polypropylene and in reality, are gradient density filters in that the outer layers trap larger particles so that the inside layers are more efficient. They are often called “melt blown” or “spun poly” filters. These filters are generally used in reverse osmosis pre-treatment, food and beverage, microelectronics, and many other applications. Made out of 100% pure polypropylene, a spun polypropylene filter is suitable for any potable water application, including high-purity. There are no glues, binders or additives that can cause side effects in water processing applications. However, you wouldn't want to use a Spun Poly filter for a point-of-entry or whole house application, because it would plug too quickly. Point-of-Entry Filtration (POE) is typically for filtration for a whole house or business and the fact of the matter is that there are two types of homes or businesses: (1) Those that have POE Filtration; and (2) those that need it! There is no question that any home or business can reap great benefits from having a Point-Of-Entry Filtration System. Why? Even on city water, there is sand, silt, grit and other things that can cause problems with icemakers, toilet internals, faucets and appliances like washers and water dispensers. If you have a water softener, you can even extend its' life and prevent unnecessary service by simply having a pre-filter ahead of it. There is probably not a single instance where simple filtration does not provide substantial benefits. So, that bring up three questions:

1. What type of filter is best?
2. What size is best?
3. What micron rating is best?

This is where it gets dicey. The easy part is deciding what type of filter is best. As mentioned a Spun Poly Sediment Depth Filter is not appropriate in this case, but some people use string-wound filters for a couple or reasons (1) they are the lowest cost filters; and (2) you don't have to change them very often... OF COURSE YOU DON"T BECAUSE THEY DON'T TRAP AS MUCH SEDIMENT AS A PLEATED FILTER! Look, string wound filters are better than no filters and they are inexpensive, but a pleated filter has more surface area, traps more sediment, sand, silt and grit than any string-wound filter and are cleanable and reusable. Even though a pleated filter has a higher price, it costs less than any string wound filter because it works so much better and you can re-use it after cleaning four or five times. Hands down, a pleated filter is the best choice and while there are many brands of pleated filters, there can only be ONE BEST PLEATED FILTER and that is US Water Systems. That raises the question as to what size is best. It's a simple answer. For any POE filtration, you would want to use a 4.5" x 10" housing at a minimum (that would be for a small home), but it is always best to use a 4.5" x 20" housing for better flow rates. Don't go too small - a 2.5" filter, even if it is 20" in length is too small for a whole house. Stay with 4.5 inch by 20 inch housings when you are treating a whole house for sediment. Insofar as micron rating, it is very site specific. In many cases, a 5 micron filter works great, but in other cases it works best with a 10 or 20 micron filter because you may have larger particles to trap. It's a good idea to start with a 10 micron filter and then see how effective that is. You can go up or down in micron size, based upon that or go up if it plugs too quickly. Step-down filtration is also quite effective (pictured at the right). That is where you might start with a 20 micron filter, followed by a 10 micron filter followed by a 5 micron filter. This would be utilized when you have sand, silt and sediment in large quantities. In conclusion, when dealing with whole house filtration, use larger filters such as a 4.5" x 20" housing, use a pleated cartridge and make sure you use the correct micron size for your application.