How to Install a UV Water Filter (Step-by-Step Guide)

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UV water purifiers are one of the best defenses against harmful microorganisms, using ultraviolet light to scramble the DNA of bacteria, viruses, and protozoans.

If you’re considering an ultraviolet purifier for your home, or you’ve already bought one, you’re probably keen to know about the installation process.

  • What equipment do you need to connect a UV water purifier to your water lines?
  • How easy is the installation process, and what’s involved?
  • Do you need to be a plumbing expert, or can you do it yourself?
  • How do you insert a new UV lamp?

We’ve covered everything you need to know in this UV installation guide.

installing a uv light for well water

📝 How to Install a UV Water Purifier System

To hook up a UV water purifier to your plumbing, here’s what you’ll need to do. Please also cross reference the user/installation guide for your specific model if needed.

Tools/ Equipment:

  • Sediment pre-filter
  • UV chamber
  • UV light
  • Quartz glass sleeve
  • Flexible tubing
  • Teflon tape
  • Mounting brackets


  1. Mount the sediment pre-filter. Mount the sediment pre-filter housing to the wall using the included fittings and brackets, then insert the filter cartridge.
  2. Mount the UV system. Attach the UV system to the wall, downstream of the sediment filter. Leave enough space around the unit to allow for proper maintenance.
  3. Plumb in the UV unit. Connect the flexible tubing to your plumbing and the UV unit, following the instructions in your user manual. Keep in mind that UV light degrades plastic, so don’t use plastic fittings.
  4. Insert the lamp. Slot the lamp into the sleeve and slide it into the chamber.
  5. Plug the unit in. Plug the unit into your power supply and switch it on.
  6. Check for leaks. If you notice leaks around the fittings or connections, tighten them or use Teflon tape to secure the connections.

💡 How to Install a UV Lamp

To insert a new or replacement UV bulb into your unit, follow these steps:

Tools. Equipment:

  • New UV bulb
  • Cloth or protective gloves


  1. Switch off power and water. Switch off your water and unplug the system from your power supply.
  2. Insert the sleeve. If you’re installing the glass quartz sleeve at the same time as the lamp, insert the sleeve into the UV chamber. Use a cloth or protective gloves to avoid directly touching the sleeve – your fingerprints could tarnish the sleeve.
  3. Insert the UV lamp. Once the sleeve is slotted all the way in, slide the lamp into the quartz sleeve.  
  4. Reassemble the system. Reconnect the other parts of the unit.
  5. Switch on power and water. Plug the unit back into your power supply and switch on the water.
Installing the uv lamp

📖 How Does a UV Water Purifier Work?

A UV water purifier emits ultraviolet light, which deactivates the DNA of microorganisms like bacteria and viruses. When their DNS is deactivated, the living organisms in your water won’t be able to reproduce or cause disease.

🔧 Installing A Pre-Filter Before the UV System

UV water treatment is only effective when the treated tap water is clear.

For this reason, the majority of manufacturers of UV systems recommend installing a sediment filter (usually 5 microns) upstream of the system.

This prevents shadowing, which occurs when large particles of sediment block the UV light from reaching the living organisms during UV disinfection, meaning that not all microorganisms are effectively treated.

A whole-house sediment pre-filter is designed to trap large sediment that could prevent the ultraviolet light from reaching all the bacteria, viruses, and protozoans in the water.

UV whole house water filter system diagram

🔀 When to Replace a UV Lamp

Once you’ve installed a UV water purifier, your job is done – but only temporarily. You’ll need to make sure to replace the UV lamp as recommended by the manufacturer to keep the system operating effectively.

Most UV lamps have a 9,000-hour lifespan, which equates to just over 12 months. Your UV system might have a reminder light or alarm that sounds when you need to replace the lamp. The lamp will become up to 60% less effective once it reaches the end of its lifespan, so replacing it on time is essential.

✅ Things to Consider when Installing a UV Purifier

When you’re installing a UV system at your water line, you’ll benefit from considering the following:

1. Locate the UV Unit After Other Water Treatment Systems

Your UV water purifier should be installed before your hot water heater, but downstream of all other water treatment systems in your home – such as water softeners, reverse osmosis systems, well pumps and pressure tanks, water filters, and de-ionizers. This means that your water will be at its cleanest and highest quality by the time it reaches the UV lamp, and reduces the risk of decontamination after your water has been purified.

2. Mount the UV Water Purifier to a Wall

If your UV system doesn’t already come with a wall mount, you’ll need to buy a separate bracket or clamp mount to attach the unit to your wall. Mounting your unit to the wall doesn’t just look cleaner; it also reduces the potential for the unit to become damaged from being installed on the floor, and reduces the potential for overheating by allowing air to freely circulate the ballast housing.

Mounting the whole house uv water filter to the wall

3. Install a Shut-Off Valve on Either Side of the Unit

A shut-off valve lets you isolate the UV purifier from your water supply when you’re performing maintenance or you can’t use it. This means you can still get access to water while you’re replacing the lamp and cleaning the quartz sleeve – it just won’t be purified.

4. Keep an Extra Quartz Sleeve and Lamp on Hand

You won’t get much notice that your UV lamp needs changing. If the alarm starts sounding and you realize you don’t have a new lamp to hand, your water will be unprotected until you can buy one. The quartz sleeve lasts longer than the lamp, but it’s prone to breaking, so it’s a good idea to have an extra sleeve to hand, too, in case of emergencies.

Related Content:

🧠 UV Water Purifier Installation FAQs

How much does it cost to install a UV light in a well?

The average cost of buying and installing a UV light depends on whether you plan to install the unit yourself. If you choose DIY installation, expect to spend $600-$1,200 in total. Professional installation of a UV disinfection system is an extra $100-$300 on top of the purchase price.

Does UV light work on well water?

Yes, UV light works on well water. However, the UV rays may struggle to penetrate your water if it’s sediment-rich or turbid. In this case, you’ll need to install a sediment pre-filter upstream of the UV water system. This will remove the particulate matter and allow the UV rays to penetrate all of the water that flows through the system.

Is a UV filter necessary for water?

It depends on what your water contains. If there’s a chance that your water could contain coliform bacteria – a common problem in well water systems – a UV filter can protect you from this microorganism.

In most cases, UV water systems aren’t necessary, but people install them for peace of mind that they’ll be protected against contamination of their water supply.

Should I get a professional to install my UV water purifier for me?

Installing a UV water purifier is relatively easy, and most people should be capable of doing it themselves. However, if you’re physically unable to do the job, or you just don’t want to, you can hire a professional plumber or handyman to handle the installation process on your behalf.

Should a UV filter be before or after a filter

You should locate your ultraviolet system downstream of any whole-house filtration system. This means your water source will be greatly improved in quality by the time it reaches your UV filter, and will contain fewer contaminants that could potentially shield the microorganisms from the UV light and reduce the effectiveness of purification.

Should a UV light be installed before or after water softener?

A UV purifier should be placed downstream of a water softener. This means that the water flowing into the UV purifier has been softened, and won’t deposit limescale on the glass sleeve and affect the system’s purification capabilities.

Does a UV system affect flow rate?

No. A UV system won’t affect your flow rate at all. There are no filters or tanks for the water to flow through – just a UV chamber.

  • Jennifer Byrd
    Water Treatment Specialist

    For 20+ years, Jennifer has championed clean water. From navigating operations to leading sales, she's tackled diverse industry challenges. Now, at Redbird Water, she crafts personalized solutions for homes, businesses, and factories. A past Chamber President and industry advocate, Jennifer leverages her expertise in cutting-edge filtration and custom design to transform water concerns into crystal-clear solutions.

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