How do Water Filters Work?

To filter or not to filter: that is the question. The efficacy and necessity of the water filter is perhaps the most divisive of the totally mundane household preference arguments, along with the legendary “should we refrigerate our bread?” (yes) and “should we twist-tie our bags or twirl-and-tuck?” (twist-tie).

So: should you filter your water? We already know that Dallas’ water is clean, so how could a filter help? What do household water filters really do? How do they work? Why do some people swear by them, while others scoff? Here’s how the most common household water filters work, why some people use them, and whether or not you should consider getting one.

How Water Filtration Works

What is Water Filtration?

Water naturally collects all kinds of debris. Some of this debris is big enough to see–obvious stuff like sticks, stones, sand, or bugs. Because water is so good at dissolving things, however, it also picks up a lot of tiny debris. Rock, plastic, or metal sediment builds up as water flow shaves it away. Germs and bacteria live in water, as well. Water filtration is the process of taking materials like these out of water to make it safe for people to use.

Water filters work in several ways. A city municipal system chemically treats and mechanically filters tap water. Chemical treatment involves adding cleaning agents into water to kill germs or separate buildup. Mechanical filtering involves using constructions like porous barriers to “catch” materials. Most home water filters use the same basic mechanical filtration process as a municipal system does, but on a much smaller scale.

How does Mechanical Water Filtration Work?

Mechanical water filtration works by setting up barriers between the water and where it’s going. These barriers contain tiny pores just big enough for water to pass through–but (hopefully) not big enough for anything solid. The water filter “catches” anything floating in the water. Consequently, the water coming out the other side of the filter is cleaner and safer to drink.

Home filters have a pore-size efficiency, which determines filtration effectiveness. Pore-size efficiency measures how small the filter’s openings are. The smaller the pores the less solid material can pass through. Pore-size efficiency is measured in “microns”; one micron is 1/1000 of a millimeter!  To successfully stop microscopic bacteria, a water filter has to have pores smaller than 0.4 microns! That’s tiny. How tiny? A credit card is about a millimeter thick. Imagine something a thousand times smaller.

Water Filter

Why Do People Like Using Water Filters?

There’s a persistent myth that tap water is unsafe to drink. We know, at least in Dallas, that this myth is not true. Your city has already extensively filtered and treated your tap water before you use it.

Despite the safety of tap water, water filters aren’t just for hypochondriacs. Chemicals introduced to tap water during the cleaning process may be unhealthy to drink. It’s possible for bacteria and other germs to enter water after it undergoes the treatment process. If your pipes are old or corroded, water may shave away sediment or metal shavings, which will then get into your water supply. Though its ultimate usefulness depends largely on the water quality of the system, water filters can be considered a “last line of defense” for those who want to make sure their water is safe.

What Should I Look For in a Water Filter?

The water filter you’ll want depends on your personal needs. There are filters that attach to water bottles, that are built into pitchers, that come with a water-supplying appliance, or that you install directly onto your faucets. Most high-quality home water filters are made of activated carbon. This is an ideal filtering substance because the openings in carbon can be microscopic. Even better, the carbon has the added effect of weakening the chemical bonds between molecules and water, making it easier to filter out chemicals.

If you’re interested in finding a water filter for your house, you should know that permanent, installation filters tend to work better and last longer than pitcher or bottle-based versions. Look for an activated carbon filter, and check to see if it has a pore-size efficiency rating in microns advertised on the box. Finally, remember that filters don’t actually remove buildup; they catch it. That means as filters do their jobs, they’re going to get dirty. Check the instructions in your specific filter to figure out how often you should replace your filter, and follow a routine.

We realize this probably didn’t clear up any contentious arguments, but hopefully you at least have a better idea of where you stand and why. If you’re looking for a good water filtration system for your house, we can make suggestions and even install one for you quickly and effectively.

If you find that your water tastes bad or doesn’t look right, it could be a sign that your plumbing is in peril. Give Ben Franklin a call anytime with questions or to schedule an appointment. We won’t argue about your water filter. Much.