These days there’s a spotlight on ultraviolet light, and for good reason: UV’s ability to disinfect has made it an attractive soldier for places like hospitals, subways, restaurants and jails. Even individual germophobes anxious about what’s lurking on their countertops and phones are snapping up personal UV sanitizers.
Yet UV disinfection systems have long been star performers for treating water, especially in well water treatment. Some people think of the disinfection technology as a UV water filter—perhaps because so many filters play important roles in treating household water. UV works differently, though. It kills microorganisms instead of actually filtering anything out.
UV effectively protects against waterborne microorganisms that can make us sick, like E. coli and other bacteria as well as viruses, mold, and protozoa like Giardia and Cryptosporidium. Unlike chlorine, a chemical that also kills pathogens, UV light is a physical disinfectant that doesn’t change the taste and smell of water.
Rather than being a UV filter, the treatment involves a cylinder with a UV lamp that emits a wavelength beyond the visible spectrum. The light disinfects water that flows past by attacking the DNA of microbes and making them unable to survive.
The output of the lamp, which runs on electricity and can generate heat, typically declines over time. Replacing it each year is a good idea. It’s also recommended to annually clean or replace the glass tube that houses the lamp and keeps it dry, which is called a quartz sleeve.
The germicidal light does a great job attacking microorganisms, but it doesn’t destroy everything you may want taken out of your water. For instance, UV won’t remove contaminants like arsenic or the dangerous chemical compounds known as PFOA/PFAS.* Nor will it take care of sediment, particles, or minerals that create hardness in water, like calcium and magnesium. You’ll need other types of home water softening systems or whole home filtration systems to handle those issues.
In fact, depending on your water quality, it may be necessary to run your water through some filters before it flows past your UV lamp. You don’t want substances collecting on the quartz sleeve, acting as floating shields for microbes, or doing other things that could inhibit the light from doing its job. Using—and maintaining—pre-filters like a five-micron sediment filter and a softener can help your UV operate at peak efficiency.
Like many other home water treatment solutions, you can decide where to install your UV. You can disinfect all the water you use in your home by placing it at the point-of-entry, which is where the main water line enters a home. It doesn’t restrict water flow, so it won’t affect your water pressure. If you’re only concerned about treating the water you drink, however, you can install a smaller UV unit with pre-filters under the kitchen sink.
UV is appealing to many residents whose water sources are private wells, which aren’t regulated and can be contaminated in many ways. Underground storage tanks can leak, for example, and water run-off can deposit animal waste and other harmful substances. Routine and more advanced water tests can reveal potential problems in your water, but they can be mere snapshots in time. Water quality can change quickly in wells, and UV can offer a layer of protection and help ensure safe conditions year-round.
The technology also has a role to play in homes that get their water from public water systems. To be sure, in the U.S. these suppliers must regularly test their supply and follow legal limits the EPA has set on more than 90 contaminants in drinking water. The systems typically use filtration, a disinfectant like chlorine, and other processes to rid water of germs. (Your water company’s annual Consumer Confidence Report, or CCR, should list the regulated contaminants that have been detected in the water.) In Canada, Guidelines for Canadian Drinking Water Quality are set by Health Canada’s Water and Air Quality Bureau in partnership with the provinces, territories and other federal departments.
Nonetheless, quality problems can occasionally pop up. Biological contamination may occur after a water main breaks, for instance. Additionally, issues may occur as the water supply travels from the municipality to the home, through supply lines or potentially fixtures within the home.
Your local Culligan Water Expert can help you understand if UV is a good option for you and, if so, can suggest a system with a size that’s appropriate for the flow rate of your water.
Ultimately, UV is a reliable, highly effective and low-maintenance water treatment option that can give you peace of mind that your water is cleaner and safer.
* Contaminants may not necessarily be in your water.