The Complete Handbook of Shower Water Filters

Chapter 1: Understanding Shower Water Filters

Shower water filters are point-of-use devices installed in the plumbing line between your shower valve and the shower head. They come in a variety of physical formats, but they all share a single engineering purpose: to alter the chemistry or particulate content of the water that reaches the bather. That broad description covers a wide range of actual performance, from simple particulate screens to redox media that change the oxidation state of dissolved metals. The most important thing to understand is that a shower filter is not a generalized purifier. It is a targeted device with specific capabilities and specific limitations, and judging it by inappropriate criteria (like expecting it to remove dissolved salt) is a common source of consumer confusion.

To understand the category properly, you need to start with the water itself. Municipal water supplies are treated and safe to drink, but they are not chemically neutral. Most utilities add a disinfectant, typically chlorine or monochloramine, to control bacterial growth in the distribution network. Water hardness—calcium and magnesium ions—varies dramatically by region. Iron, manganese, and hydrogen sulfide are common in well water or in areas with mineral-rich aquifers. And even in municipalities with excellent water, the pipes in your building can contribute rust, scale flakes, and sediment to the water that reaches the shower head. The shower filter sits at the end of this long chain, and it is the last chance to address any of these issues before the water hits