One of the great aspects of Ultraviolet or UV water disinfection for well or surface water is that it’s a light disinfection process and does not add any potentially harmful chemicals to your family’s water. UV systems will kill all the bacteria in your water as the water passes through the UV, but what about the potentially infected water that is downstream of the UV?

Since there isn’t a disinfection residual, it’s important that the entire plumbing system located after the UV be chemically disinfected initially to ensure that the water is free from any bacteriological contaminants. The disinfection process must be performed as part of the UV installation and repeated whenever the UV is shut down for service, it’s operated without power (like during a power outage), or had been inoperative for any reason.

1) Shut off the upstream water supply that feeds water into the Ultraviolet Disinfection System and depressurize your water system by opening a downstream faucet.

2) Remove the pre-filter cartridge from the sump nearest the UV chamber and fill the sump with 2-3 cups of household (5.25%) bleach (chlorine) and close the sump. At all times during this process, make sure the UV system (and lamp) is turned on and operational!

3) Re-pressurize water system by turning the water back on.

4) Starting with the faucet farthest away and working your way back, open each faucet and allow cold water to run until you detect chlorine using hot tub test strips, as shown in this YouTube video of mine https://youtu.be/1dD2eavyb5E and then immediately shut the faucet off and repeat the process for each faucet and fixture. You must ensure that all water sources located after the UV, including outside faucets, dishwashers, shower heads, washing machines, connections to refrigerators, toilets, etc., pass chlorinated water.

5) Once you‘ve finished with the cold water, repeat the whole process with the hot water. The hot water may need to run for quite awhile before you detect the chlorine because of the large quantity of water in the hot water tank which will dilute the chlorine. Again, make sure you get a chlorine residual at every hot water source.

6) Once all the water locations have passed chlorine, you will need to leave the chlorine sit in the pipes for a period of 4 hours. Do not use any water during this time. The chlorine needs this contact time to make sure it kills all of the bacteria in your home, cottage or cabin.

7) Reinstall the pre-filter cartridge into the filter housing.

8) After 4 hours, flush the chlorine solution from the system until the chlorine smell is gone. Don’t be surprised if there is a lot of discoloured water coming out of the faucets. Make sure that each fixture that was disinfected is completely flushed of chlorine.

Do not consume water until complete system has been flushed. Run the washing machine without clothes in it to flush out all of the chlorine.