Fitness Equipment

How To Install An Ultraviolet (Uv) Light Water Filter

By C. Reid Thornley B.Sc.

Many rural homeowners depend on a water well to provide their family with a safe and clean water source for drinking, food preparation, and for washing. Unfortunately many people discover that their once pristine well water has become contaminated with bacteria. This can happen when septic beds are placed too close to the well, or when surface water is allowed to enter the well cap.

At this point most homeowners look to modern technology to rid them of the bacterial contamination in their well. For many homeowners the top choice is an Ultraviolet (UV) water purification device. Installing a UV system is straightforward and only requires limited plumbing and technical expertise.

The first step to installing a UV system is determining where it should go. Ideally a model should be chosen that is capable of treating the water for the whole home. A model that will treat 10 gallons per minute will usually suffice. The ultraviolet system is plumbed on the main water line and should be the last piece of water purification equipment before the water is piped to the rest of the home. So, if a water softener or iron filter is present, the ultraviolet system should sit after the softener. It’s also important to note that a 5-micron sediment filter must be installed before all UV systems. The typical order of equipment for a home with a well is: well pump, pressure tank, water softener, 5-micron filter, UV system, tap.


From an installation standpoint, a UV system is really just a glorified piece of threaded pipe. Most home systems will have 3/4″ NPT nipples. It’s best to plumb the UV system with copper. UV light will quickly break down plastic to the point of failure so it’s not advisable to plumb the UV system with PVC or flexible plastic tubing. Many professional installers will use unions so that the UV system can be easily removed if servicing is required in the future. When attaching the unions or other fittings remember to use three or four passes of teflon tape to ensure a good seal. A putty crayon can also be used with equally successful results. Make sure the ultraviolet system is installed with enough clearance to allow the UV lamp to be inserted and removed. UV lamps need to be replaced yearly.

UV systems require standard 120V AC power. It’s always best to use a Ground Fault Circuit Interrupter (GFCI) outlet when powering a device that is exposed to water. It’s also ideal to locate the power receptacle above the water lines. This way if any leaks occur, or when you change the UV lamp, water can’t run down the power cord into the receptacle. If you live in an area that experiences regular power interruptions it’s also a very good idea to plug the UV system into a surge suppressor. This may save you from having to replace the UV system’s expensive power supply.

The final step in the installation of a UV system is shocking all the household plumbing with bleach. By passing bleach through all the plumbing lines in the home the installer ensures that water that is treated by the UV system can’t be re-contaminated by bacteria growing in the plumbing lines. The easiest way to shock the lines is to open the 5-micron filter housing, remove the filter cartridge, and fill the filter sump with regular household bleach. Screw the sump back onto the filter housing and now go to each tap, toilet, faucet, and hose bib in the house and run it until you smell bleach. You may have to refill the filter sump with bleach several times. Once all of the lines are full of the bleach-water mixture it’s best to wait about two hours and then flush all lines with water until the bleach smell is gone. Remember to put the 5-micron filter cartridge back in the housing.

Remember, even though the UV lamp is not “burned out” after a year, it must still be replaced. UV lamps lose intensity over time and after a year a lamp does not have enough intensity to ensure that your water is being treated properly.

About the Author: C. Reid Thornley is a B.Sc. Biology and a former research associate for a world class water purification manufacturer. He has been a presenter for the US Water Quality Association and he now owns and operates

aQuatell – Ultraviolet (UV) Water Filters, Water Softeners, Reverse Osmosis Systems, Water Distillers, and Water Softners



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