If you’ve ever shopped for water filtration systems, you know how overwhelming it can be. Each technology has specific contaminants it can or cannot filter, so it’s sometimes necessary to make a tradeoff. Plus, if you don’t first test the tap water in your home to see which contaminants are (or are not) an issue, how can you know which filter you need?
In this article, we’ll summarize the more popular choices in the easiest way possible, so you can spot your solution more quickly. Once you start shopping, you’ll notice that quality water filtering systems will often combine 2 or more purification technologies into a single unit, so you can capture a wider range of pollutants.
Here’s what we’ll cover below:
- Reverse Osmosis
- Activated Carbon
- Ceramic + Activated Carbon + Silver
- Water Softeners
- Distilled Water Machines
1. Reverse Osmosis (RO)
What it removes: Reverse osmosis (RO) systems remove almost everything: bacteria/microorganisms, arsenic, fluoride, hexavalent chromium, nitrates, some pharmaceuticals, and perchlorate. In fact, RO filtration is so comprehensive that ALL minerals are removed, including beneficial minerals. For this reason, RO systems will often include a module that adds back calcium, magnesium, and (sometimes) other minerals. To fully replace the natural minerals that RO removes, users will often supplement with drops of seawater.
What it does not remove: Reverse osmosis systems (on their own) do not remove chlorine, trihalomethanes, radon, pesticides, and volatile organic compounds (VOCs). Most RO systems will address this deficiency by adding carbon and/or ceramic filters.
Where/how it’s used: RO filtration systems are either fitted to individual taps (usually the kitchen sink) or plumbed into the entire house through the main line.
Relative cost: While RO units are not prohibitively expensive, hiring a plumber to install them can be. They can also add quite a bit to your water bill, as they are extremely wasteful, requiring roughly 20 times more water than they produce. So while RO units can be installed as whole-house filtration, it’s best to install RO directly under the sink for cooking and drinking and not for showering, laundry, or toilet flushing.
2. Activated Carbon
There are two types: granulated carbon (less effective) and carbon block (more effective).
What it removes: The efficacy of carbon systems varies greatly. Some (typically the granulated carbon) only remove chlorine and are meant solely to improve taste and odor. Others (typically the carbon block) also remove solvents, pesticides, VOCs, mercury, lead, asbestos, some radioactive contaminants, large parasites, and some pharmaceuticals.
What it does not remove: Carbon filters do not remove bacteria, asbestos, arsenic, chromium, fluoride, perchlorates, heavy metals, and some radioactive compounds.
Where/how it’s used: You’ll usually find granulated carbon used in water pitchers, sink & shower faucets, refrigerator taps, sports bottles. By contrast, the carbon blocks may be plumbed into the main line or to individual taps. They are also sold as separate countertop units.
Relative cost: Initially, carbon filtering solutions are low cost. But replacing the filters can add up over time.
3. Ceramic + Activated Carbon + Silver
What it removes: Ceramic alone can block only solid contaminants such as cysts and sediment. But when combined with carbon and silver (which is a powerful antibiotic) the system also removes bacteria and parasites, chlorine, some radioactive contaminants, some pharmaceuticals, most solvents, pesticides, chemicals, and some heavy metals.
What it does not remove: Fluoride, some heavy metals, viruses, and very small microbes.
Where/how it’s used: These usually come as cartridges that are installed under the sink, so some plumbing is required.
Relative cost: These combo systems are relatively low cost to purchase and to install. Their filter life is also pretty good, so they are not expensive to maintain.
Aquasana Water Filtration Systems
4. Water Softeners
(Also known as deionization or ion exchange)
What it removes: Water softening systems remove barium, radium, mineral salts (that can build up in pipes and fixtures), and other electrically charged molecules (ions).
NOTE: The water softening process uses sodium to replace minerals, such as calcium and magnesium. As a result, water softeners are not recommended for those seeking to lower their sodium intake. They are also not advised for watering plants and gardens.
What it does not remove: Water softening systems do not remove microorganisms, VOCs, pharmaceuticals, and most other contaminants
Where/how it’s used: Water softening systems are typically plumbed into the mainline for use throughout the house.
Relative cost: They are relatively low cost to purchase, install and maintain.
5. Distilled Water Machines
What it removes: Distilled water machines heat your water enough to vaporize it, while leaving most minerals, heavy metals, and chemical contaminants in their liquid states in order to separate them from the steam. The machine then condenses the steam back into the water. The process is highly effective at removing most bacteria, viruses, and chemicals, however (like reverse osmosis) it also removes beneficial minerals and is therefore not recommended to drink regularly without re-mineralizing the water.
What it does not remove: Distillation removes chlorine, VOCs, insecticides, herbicides, trihalomethanes, and other contaminants that have a lower boiling point than water.
Where/how it’s used: These are commonly found as countertop machines.
Relative cost: Distillation machines range from moderately to very expensive.
Good to Know
The quality of water filters can vary widely, so be sure to check the brand’s website or packaging to ensure it has been independently tested and certified by a reputable agency (such as NSF or the Water Quality Association) to remove the contaminants that it claims it does.
Also, read the labels closely, as the words “NSF certified” alone only tells you that the filter is certified for something. But it’s up to you to read the fine print to see what exactly the filter is certified to remove.
For example, are they only certified for removing chlorine? Or does the certification cover everything they list on the front of the box? You have to check.
Aquasana Water Filtration Systems
A Note On Big Berkey Water Filters
I’ve owned a Big Berkey Water System for ages and the water really does tastes better than any filtered water I’ve tried. In researching this article, I also found that both their shower and drinking water filters are popular among folks who suffer from extreme chemical sensitivities, as they tend to do a great job in curbing the adverse reactions these folks were experiencing from the contaminants in their tap water.
However, something bugged me when I was researching Berkey and my skepticism was later validated by New York Times journalist, Dan Koeppel, who recommended I read this Wirecutter article. I’m thankful he brought it to my attention.
I spent a considerable amount of time trying to find information regarding exactly what makes up Berkey’s filters, but all I could dig up was that they were made from “6 different filtering elements”. Which six? No idea. And Wirecutter couldn’t find the info either. This should be readily available on their website and I’m a stickler for transparency, yet I almost gave Berkey a pass, simply because I’ve been a customer for so long and because they’re so beloved by the chemically sensitive.
By the way, I also didn’t realize that Berkey isn’t certified, or even tested, to NSF standards. In this article (and in person), I always encourage folks to check for this testing. Yet again, I didn’t follow my own advice, because I just assumed they were certified. Lesson learned.
While Wirecutter found that Berkey does do an exceptional job filtering lead, they couldn’t verify several other test results or claims made on their website. Casting further doubt, they learned “it would cost well over $1,000,000 to conduct certification testing for all of the substances” that Berkey claims their filters can remove.
Berkey’s lack of transparency with regards to their filtering elements bothers me, as does the fact that they don’t test to NSF standards. All that said, I can’t discount them entirely. Berkey’s filters are widely used by the chemically sensitive because users do experience a notable reduction in adverse reactions. So with these testimonials in mind, I can still recommend Berkey… just not as enthusiastically as I would have liked.