Choosing the Right Home Water Filter for Your Family

Choosing the right home water filter for your application can be a daunting task.  What are the differences between various types? Does it really matter if I’ve got the right microns?

I've looked all over—in stores and on the internet—and never been able to find much in the way of a “which filter is right for me?” guide.  The longer we cruised, and used filters for various purposes, the more I had to learn about the topic.  The following summarizes what I know, but always check manufacturer documentation if using a filter as part of another system, such as a watermaker—I can give some general guidelines below, but your system may have specific requirements.

Water filters—called “cartridges” by manufacturers—have 3 basic differences from one to another:

Size. Obviously, you need the right size to fit your housing.  The standard size used in most housings is called 10″ by 2-1/2″ diameter.  Note that although it’s called 10″ long, the filters are actually about 9-3/4.”  While many other sizes are available, this is the size that I discuss in my article on water filtration systems and in this article.

Type. Six types of filters are commonly found:  pleated paper, string wound, polyspun, carbon wrapped/impregnated, granular carbon and carbon block.  More on these below—the various types do look different, which can help if they are labeled in a language that you’re not totally fluent in.

Micron rating. Filters all have a micron rating on the label.  The smaller the number, the finer the filtration.  I’ve seen them as large as 40 microns, but 20, 10 and 5 are far more common.  The smallest I’ve seen is 0.5 microns.  Finer filtration can slow down water flow, but that is usually more of a problem in houses (where people expect greater flow) than in boats.

You really don’t have a choice on the size, so I’ll look at the various types and the micron ratings.  Prices that I list are for buying online in the US or in big-box stores.  In other locations, prices can vary considerably!

One online source that has pretty good prices is cnfilter.com, which graciously allowed me to use their images of the various filter types.