Short answer: you don't have to. Your tap water is treated to be safe. But "safe to drink" and "best for your skin and hair" aren't always the same thing, and that's where a filter comes in.
What's actually in shower water
Depending on where you live, shower water can contain chlorine or chloramine from water treatment, minerals like calcium and magnesium (the source of "hard" water), and small amounts of metals such as iron or copper from pipes. Each is normal on its own. Together, and every day, they can change how your skin and hair feel.
Signs your water might be the problem
- Skin feels tight or itchy right after you shower.
- Hair feels coated, heavy or straw-like, even after a fresh wash.
- Color-treated hair fades or turns brassy quickly.
- You see white crust on your showerhead or spots on the glass.
- Your bathroom smells like a swimming pool when the water's hot.
How to find out what's in yours
Every community water system in the U.S. publishes an annual Consumer Confidence Report that lists what's in the water and at what levels. Search for your city's name plus "water quality report." For a quick check at home, inexpensive test strips can show hardness and chlorine in a few minutes.
What a shower filter does
A shower filter sits between your pipes and you. As water passes through the cartridge, the filter media works to reduce things like chlorine before the water reaches your skin and hair. Different filters use different media and are designed to reduce different things, so it's worth checking what a filter is made to target.
What it won't do
A shower filter isn't a treatment for a medical condition, and it can't undo damage overnight. Think of it as removing one daily stressor, so the rest of your routine has a better chance to work.
So, should you filter?
If your skin and hair feel fine and your water is soft, you may not notice much difference. If you're dealing with dryness, build-up or fading color that products alone haven't fixed, filtering your shower water is one of the easiest things to try. It takes a few minutes to install, and the only thing that changes in your routine is the water.
Remember to replace the cartridge on schedule. A spent filter can't do its job.