Ultraviolet Disinfection for Well Water


The use of ultraviolet disinfection (uv) in water treatment has been around for almost as long as chlorine.  It’s been known for a long time that ultraviolet light mutates and degrades DNA (the same way it gives you a sunburn). However, due to the fact that it requires electricity, it didn’t really catch on commercially until the 1960’s.   Ultraviolet disinfection for well water can be an effective treatment against microbiological contamination, but it does require some pre-treatment to ensure it’s working at peak effectiveness.

How does UV work?

Typically, a UV system will be comprised of a stainless steel chamber containing a UV-producing lamp, a sleeve to protect the lamp (usually quartz), and a ballast or controller box.  As the water flows through into the stainless-steel chamber and past the lamp, and

ultraviolet disinfection

Illustration of how ultraviolet breaks down DNA in cells.

microbes in water receive a lethal dose of UV light.  The UV attacks and breaks down the organism’s DNA, making it incapable of functioning.  This also completely eliminates their ability to reproduce and infect.  The water is then safe to drink.   Even highly chlorine-resistant microbes such as giardia and cryptosporidium can be rendered harmless by UV.

This process is called a “point of contact” disinfection process, meaning that it doesn’t need contact time (or the footprint of a contact tank) to happen.  The water is disinfected as it’s demanded by you turning on a faucet.  There is nothing added to the water, and nothing is removed from the water (such as desirable minerals).  There is no need to handle potentially dangerous chemicals, and there is less worry of chemical corrosion of your plumbing.  The lack of chemicals also means that no potentially hazardous disinfection byproducts are produced.

Maintaining a UV system is as simple as changing the UV-producing bulb (called a “lamp”), and cleaning the protective quartz sleeve once a year.  Old lamps can be easily recycled, and new lamps are relatively inexpensive and simple to install by a homeowner.

Ultraviolet disinfection for well water DOES require pre-treatment.  If there are large particles (turbidity) or heavy minerals in the water, these materials can shield microbes from UV light by hiding behind them as they pass the lamp.  This prevents complete disinfection of the water.  When proper pre-treatment is in place, UV is 99.99% effective at eliminating microbiological contaminants from your water.  For more information about uv disinfection, check out knowuv.com.