How to Install the Ultraviolet (UV) Water Filter

If you really want to be sure your water at home is safe enough to drink, you may want to consider putting in an ultraviolet water filter for your home water. With the UV water filter, you can kill the germs that can cause dangerous diseases like diphtheria or cholera. This is especially important when you’re dealing with untreated well water. 

Of course, to make sure the UV filter works, you’re going to have to make sure you install it correctly. So it’s best that you read over the manual instructions and you follow the steps to the letter. Each type of UV water filter may have its own special installation requirements. 

In general, however, you need to focus on the following items:

Pick the Right Wattage

The UV filter usually has a GPM rating indicating the water flow for which it’s rated. In an average household, a GPM rating of 10 gallons per minute should suffice. That’s good enough for a 2-bathroom home. Here are some flowrate guidelines:

  • 1 bathroom. 6 GPM
  • 2 bathrooms. 9 GPM
  • 3 bathrooms. 12 GPM
  • 4 bathrooms. 15 GPM
  • 5 bathrooms. 18 GPM

It’s best if you are on the safe side, which is why for a normal household you’ll want a 10-GPM rating. If your home has 4 bathrooms, having a 20-GPM rating is good insurance. 

Of course, having a higher GPM rating does add to the cost. But you’ll want to balance this factor with the consideration of making sure the water is actually safe. It’s very easy to underestimate how much water you’re using within a given time. In the mornings when everyone’s taking a shower at the same time before breakfast, you may be using up a lot of water in just a short period of time.

Where Will You Put the Filter?

In most cases, you’re not actually using a UV filter all by its lonesome. In general, this means you’re putting this layer of filtration as an addition to your current water filtration system. In most cases, the UV filter layer is the very last in the series of filter media you’re using. The particle filter, carbon filter, or the water softener should be ahead. Once the water has gone through the UV filter, it’s ready enough to drink or shower with. 

You should pick a spot where you have an electrical outlet nearby, so you can power your UV filter. The area should also have maybe 2 feet of clearance space at the UV lamp cord end to let you do maintenance procedures without having to remove the disinfection chamber from the mounting bracket. 

You also may spill some water during the filter replacement, so for additional protection you may want to put in a drain pan underneath the UV filter. Still, the best area is where any spilled water won’t get to any electrical components. 

Specific Steps

Now that you have the location picked out, here are the particular steps you need to do:

  1. Find the main water supply valve and shut it off. 
  2. Usually you’ll have a mounting bracket for your UV filter, so use this to mount your UV unit to the wall. This may include mounting ballast on the bracket above and beside the chamber. 
  3. Put in the new plumbing. Ideally, you should install the UV vertically as this will be easier to service later on.
  4. Put in the quartz sleeve into the UV housing. If you’ve installed the UV vertically, the open end of the quartz sleeve will be facing up. 
  5. Put a lubricated O-ring on each end of the quartz sleeve.
  6. Tighten the gland nuts on each end by hand. 
  7. Put in the lamp spring and the lamp into the quartz sleeve. 
  8. While you hold the top of the lamp, attach the lamp to the lamp connector. Push the lamp connector down securely into the gland nut, then tighten the retainer screw. Line up the 4 pins carefully, so you can connect this properly. 
  9. Take out the nut from the ground stud at the top of the UV unit. 
  10. Put the ground wire over the stud and then tighten. 
  11. Open the valves on both sides of the disinfection chamber, then check for any leaks. Open the supply valve slowly and bleed the air from the system.
  12. Connect the UV power source to your AC line. Now you’re ready. 

Additional Tips:

Put In Shutoff Valves Before and After the Unit

Both the inlet and the outlet sides of your UV filter need to have a shutoff valve. This will certainly help with maintenance. You’ll need to isolate the UV filter from your water supply when you’re removing the quartz sleeve for replacement. 

Plumb Your UV System with Copper

You don’t really want plastic for your plumbing when the filter involves ultraviolet radiation. Even PVC isn’t really optimal. All these materials can degrade from the ultraviolet rays you’re using to kill the germs in the water. 

Instead, use copper. This material can stand the exposure to UV rays. Then to reinforce the joints of your piping system, you can just use Teflon tape or putty. 

Use Bleach

Mix some bleach with water and pour the solution through your piping system. This solution will kill the bacteria in the pipes after your UV filter. If you don’t do this, you run the risk of re-infecting the water with bacteria after you’ve run it through the UV filter. 

After using the bleach, wash the system with water several times over until you don’t even get the faintest smell of bleach from the water coming out the tap. 


It’s best if you replace your UV lamp every year, just to be on the safe side. Maybe you should have an extra lamp in reserve, so you can replace a malfunctioning lamp on short notice. A new quartz sleeve in reserve is also a good idea, because these things tend to break every now and then.

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