Are you a city water user, or a well water user? Whatever your answer, you have likely drank water that was disinfected with chlorine. Chlorine was instrumental in the creation of the first municipal water systems due to its efficiency as an anti-bacterial agent, and is now a popular choice for well water users looking to disinfect their wells and/or pre-treat their water before various types of filtration. In recent years, however, ultraviolet light has become an increasingly popular alternative for disinfecting water supplies among well water users and even in some municipal systems. With UV adoption on the rise, it’s no wonder we have started to receive questions about its efficacy as a disinfectant compared to that old standard, chlorine.
The simple answer is that UV light can be very effective in the right conditions, though attaining these conditions if your water doesn’t already meet them will often cost you more time and money than simply using chlorine.
That is to say that UV light requires clean, particle- and mineral-free water to penetrate and disinfect reliably. If your water is already clean and susceptible to UV penetration, a UV sterilizer will work very well for you; if not, you’ll need to install the appropriate pre-treatment systems before your UV sterilizer to see the desired results. Needless to say this can get expensive and create quite a bit of work, depending on the quality of your water – this is why chlorine injection pumps are often the preferred method of water disinfection.
Besides UV light’s stringent water quality requirements, chlorine is often preferred due to its low cost and easy maintenance. Once your pump is up and running, it is very easy to adjust the amount of chlorine injected, and you can even install optional modules that will adjust this amount on the fly depending on how much water is flowing from your well. Other advantages to chlorine include:
- Kills bacteria, viruses as long as there is enough contact time with the chlorine, for the chlorine to work.
- Simple, inexpensive, and easy to monitor. If the contact tank is properly sized for the flow rate, a simple free-chlorine check with an inexpensive test kit can indicate if the water is disinfected.
- Chlorine kills odors and oxidizes iron to a form that can be removed by filtration.
- Chlorine residual remains in pipes, so that bacteria cannot re-grow, or develop in the pipes later.
This is not to say that ultraviolet light is not a good choice. UV is a powerful disinfectant that can kill bacteria, viruses and parasites, provided the water is perfectly clean, low in minerals, and free of iron and sediment. This is why UV systems are often installed after a water softener or filtration system. And since it is often hard to tell whether your water can be effectively penetrated by UV light, some UV systems even include light monitors that monitor whether the UV light is penetrating the water, and shut off the water if a problem is detected.
If you are sure of your water’s quality – for total certainty, we recommend sending a water sample in to a lab; we offer test kits that include prepaid postage and sample mailer bottles for this purpose – or are able to purchase a fail-safe UV system with a light monitor, then you’ll likely be well served by a UV sterilizer. If your water has other problems besides bacteria, we generally recommend you consider chlorine, as it will not only disinfect your water but oxidize minerals like iron and manganese for easy filtration by one of our many high-quality water filters.
To browse our selection of water filters, along with chlorinators, UV sterilizers, and other water treatment systems, visit our online store. For further information about UV systems, chlorine, or bacteria, visit the Resources section of our website, where you’ll find a bevy of How-To Guides, FAQs, reference guides, and much more. And if you still have questions about these or any other water treatment topics, don’t hesitate to e-mail us at email@example.com or to use our online contact form for fast, personalized assistance. Thanks for reading!