When it comes to water, no two taps are alike. The substances in the H2O flowing through the pipes at home might be different than the water coming out of the taps at work.
Regardless of where you fill your water bottle, the goal is to have access to fresh, clean water that is free of toxic substances like lead—and that is where water treatment systems come in.
“Even though most public water systems do a great job of treating the water to very high levels of quality when it leaves the drinking water treatment plant, that water may have to travel through miles of pipe to reach your faucet,” explains Eric Yeggy, technical
affairs director for the Water Quality Association (wqa.org), a nonprofit representing the water treatment industry. “Along the way, [water] can pick up many different contaminants that can cause aesthetic issues,” like discoloration, odor, staining or an unpleasant taste.
“Some of those contaminants, like lead, may also be dangerous,” Yeggy continues. “In-home treatment devices can serve as an effective final barrier against unwelcome contaminants.”
With multiple treatment devices on the market, it can be difficult to know which one to choose. Here is a breakdown of five of the most popular options.
One of the oldest methods of water purification, distillation removes inorganic compounds like metals and minerals using a complex method: The systems heat water in batches until it boils and starts to vaporize; the vaporized water is fed into a condenser that cools it down and returns it to liquid form.
Distillation is effective for removing contaminants like heavy metals. However, “some contaminants that convert readily into gases, such as volatile organic chemicals, can carry over with the water vapor,” warns Rick Andrew, global business development director for water systems at NSF International (nsf.org), a nonprofit that tests and certifies such systems.
Most residential systems only produce small amounts of treated water and are often paired with other treatment systems, such as activated carbon filters, to remove additional contaminants. Distillation systems require regular cleanings and descaling. Solar distillation is popular in off-grid environments, but systems are expensive and energy intensive, according to Andrew.
Activated Carbon Filters
Replaceable cartridges can be affixed to taps or purchased as pitchers. Whole-home systems can be installed on the main waterline to capture contaminants.
|Water Testing 101|
Your local public water utility is required to provide a Consumer Confidence Report that details what contaminants, if any, are present in the water supply and the potential health impacts. Contact your public utility to request the most recent copy of the CCR.
You may still want to have your water tested. A certified water treatment professional takes samples to determine which contaminants are present and make recommendations for the right systems to remove those contaminants. If you’d prefer to DIY, contact the Water Quality Association for a list of certified drinking water testing laboratories in your state.
The Environmental Protection Agency found that activated carbon filters were the most effective for removing 32 organic contaminants, including pesticides and herbicides such as glyphosate. Yeggy points out that different brands and models are designed to capture different contaminants; before buying an activated carbon filter, have your water tested and choose a filter designed to capture the specific contaminants in your water. Refrigerators with built-in water dispensers often use activated carbon filters.
Replaceable cartridges have a limited life span. Be sure to follow the instructions on the packaging for when to change the filter (or look for models with a warning indicator like an LED light that alerts you when the lifespan is up).
Yeggy notes that carbon filters, which come in a variety of sizes and configurations, are convenient, inexpensive and effective.
Reverse Osmosis Systems
In a reverse osmosis system, water passes through a semipermeable membrane that captures contaminants. Like other water treatment options, reverse osmosis systems are designed to capture some, but not all, contaminants. Reverse osmosis only blocks molecules larger than water, so contaminants like chlorine will still get through. To increase their effectiveness, Yeggy explains, “These systems also tend to come with built-in carbon filtration stages, which further polish the quality and taste of the water.”
These undercounter or countertop units have their own separate faucets for easy access to treated water for cooking or drinking (untreated tap water is used for tasks that do not require contaminant-free H2O). This setup is designed to reduce waste.
“While the treated water passes through the semipermeable membrane, wastewater is ejected through a wasteline,” Yeggy explains. “This is the reason reverse osmosis systems are always sold with their own faucet [because] it minimizes the amount of wastewater that is generated.”
Exposing water to the right wavelength of light helps kill contaminants, including bacteria and viruses like E. coli, but cannot remove gases or heavy metals. If your water contains these types of contaminants, you might need to add additional filtration.
|Water Treatment in the Wild|
You won’t be able to carry enough water for a multi-day backcountry camping trip, which means a portable water treatment system is essential camping gear. Water filters strain out contaminants while purifiers use chemicals or ultraviolet light to remove viruses such as hepatitis A and norovirus that can be too small for filters to catch.
The filter or purifier you choose will depend on the amount of water you need to treat. Pump and gravity filters and purifiers can accommodate large volumes of water but are more expensive options. Low-cost, low-maintenance, lightweight options include squeeze filters; filters and purifiers on water bottles; and chemical options. Old-fashioned boiling can also work.
Camping retailers carry extensive selections of water treatment systems designed for backcountry travel. Browse the options and ask an expert for advice based on your specific needs.
UV systems are easy to install and inexpensive to maintain, and require no chemicals. Compared to chlorine, ultraviolet light is less effective for removing viruses and the wavelengths must be higher to inactivate viruses. If you have iron, hydrogen sulfide, calcium or magnesium in your water, you might need to replace the lamps more often as these compounds can cause staining and impair the UV power.
Andrew recommends using a class A system with a UV sensor to help gauge whether the system is working properly.
“The other consideration with UV systems is that there may be little to no residual disinfectant, so the water can’t really be stored safely after it is treated with UV without the addition of some residual disinfectant,” he adds.
The intensity of UV light decreases over time, so the lamps will need to be replaced. Look for systems with a warning device that alerts you when the intensity is too low to kill contaminants.
Deionized water has ionized particles, such as calcium, sodium, sulfates and iron, removed. The process moves water through resin beds that exchange hydrogen ions for positive ions and hydroxide ions for negative ions; the goal is to remove all of the electrically charged atoms or molecules found in water.
Most deionized systems filter water through a reverse osmosis membrane as a first step. Yeggy notes that deionization is not common in residences. Instead, he explains, “This
type of system is commonly used in clinical or laboratory applications where very high purity water is needed [but] it may sometimes be used when a home is forced to use water that can’t be effectively treated by any other means.”
The options for deionizers range from disposable cartridges and portable exchange tanks to automatic units.
While deionization produces very high-quality water, the system has a major downside, according to Yeggy: It only blocks contaminants with electrical charges, so living organisms like viruses and bacteria are not removed.