Is UV Water Purification Really Safe?

Author: Rory Mullan - Published: 2022/05/25 - Updated: 2023/01/05

Disclaimer: This page may contain affiliate links. If you buy a product or service through an affiliate link, we may earn a commission but at no additional cost to you. You can view our full affiliate disclosure here.

It’s understandable to worry about the safety of a water treatment system before diving into installing one. As far as water purification goes, UV filters have become a popular choice because of their high effectiveness level.

But like many systems, they have their pros and cons, and understanding them is an important part of using them effectively. If you follow the necessary precautions, and understand their limits, UV water purifiers are perfectly safe.

In this article, we’ll teach you how UV purifiers work, their advantages and disadvantages, and the circumstances in which they are the best option.

So, here is our guide answering the question, is UV water purification safe?


  • UV water purifiers are one of the most efficient and safest water disinfection equipment available, if used and maintained properly.
  • UV purifiers are even environmentally safe.  They merely require a minimal amount of energy.
  • Depending on the water, UV water filters must be used in conjunction with pre-filtration to prevent germs from avoiding the UV light’s effects.

Is UV Water Purification Safe to Use?

is UV water purification safe thumbnail

UV water purifiers are one of the safest and most effective water disinfection methods available on the market. They are also approved by the FDA as far as water purifying goes.

When it comes to purification and safety, UV systems have many advantages over other methods, including their chemical-free disinfection process and lack of water waste.

They also use very little power, which makes them an environmentally friendly option.

When UV Water Purifiers Are Not Enough

While UV purifiers are perfectly safe to use, they sometimes are not enough on their own to handle all the contaminants in your water. They will kill microorganisms[1] with up to 99.999% rate of effectiveness under normal conditions but won’t be able to do much about other contaminants (especially physical particles).

This includes things like heavy metals and chemicals, which UV purifiers can’t eliminate. Furthermore, these elements can actually affect the effectiveness of the UV system if not filtered out by other means.

If you are in a location that has water with high hardness levels, meaning a large amount of minerals and other physical elements, you’ll want to have some level of pre-filtration. The most common type of pre-filtration system is a fine sediment filter. While the filtering should happen before it reaches the UV purifier, you can also filter the purifier’s output for maximum assurance.

How Do UV Water Filters Work?

UV water purifiers use ultraviolet light to kill microorganisms in the water by exposing them to it. This scrambles their DNA and renders them harmless.

They target microorganisms and ideally have a 99.99-99.999% effectiveness rate at dealing with them, under normal circumstances. This includes proper maintenance of the quartz glass sleeve and UV light bulb, as well as some type of pre-filtration system for solid particles.

They are simple yet effective filtration systems that don’t need complex mechanisms, use little power, and are easy to maintain.

What Don’t They Remove?

While UV purifiers kill bacteria and other pathogens, they don’t actually remove them from the water. In fact, they can’t remove anything from water.

This is why you might want some form of pre-filtration that reduces the number of solid particles in your water, as they would otherwise limit the effectiveness of the UV purifier. These particles create blind spots where the light won’t reach the microorganisms and cause a buildup of grime on the glass sleeve that reduces the transmission of UV light.

Components Inside a UV Purifier

A UV water purifier is composed of a UV lamp that’s encased in a glass quartz sleeve. The sleeve sits inside the main chamber where the water flows and is exposed to the light. Finally, the chamber has sealing rings at each end where it connects to the house plumbing.

When is it Best to Use a UV Water Filtration System?

In general, water filtration is always a good idea. However, whether you’ll need a UV purifier or not will depend on the number of biological contaminants found in your water. If they are your main concern, UV purifiers are the most effective systems for dealing with them.

If you have a well, UV purifiers are particularly good. If you aren’t sure whether your water has a lot of contaminants, you can always get it tested.

UV purifiers work best when paired with other filtration systems that can reduce the number of solid particles in the water, as well as reduce its hardness.

Hard water is a problem for UV purifiers[2], as it reduces their effectiveness and causes build up on the glass sleeve. That’s why you want a pre-filtration system to support your UV lamp.

Pros and Cons of UV Water Purifiers

Like any system out there, UV water purifiers have their ups and downs. Let’s take a look at both!


Among the advantages, we can list their effectiveness, ease of use, and lack of chemicals involved in the disinfection process. Here’s a full list.


UV purifiers are extremely effective at neutralizing, or straight up killing, microorganisms commonly found in water. They are one of the most effective biological decontamination methods out there, and they are FDA approved too.

bacteria under microscope


Not only are UV purifiers effective, but they are also incredibly fast. They work at the same speed that your water flows. No need to wait for the purifier to finish. If the water is flowing out of the faucet, it already has been disinfected. However, UV systems are limited by the power of their lamps. Standards lamps will handle most households just fine, but if you have a really large home you’ll need a more powerful unit.

Low Maintenance + Running Costs

UV purifiers don’t need extensive or constant maintenance. All you have to do is clean the glass sleeve once a year, replace the sleeve or lamp, and check the seals for leaking.

Furthermore, they are also rather inexpensive. Thanks to their low energy use and long operation time, UV water purifiers don’t cost a lot in the long term. They are one of the most cost-effective methods available to disinfect water.

Water Retains its Taste and Smell

Since the UV purifier doesn’t affect the composition of your water, its taste and smell remain the same. There’s no strange aftertaste left when it does its job.


One big perk of UV purifiers is that they don’t need any chemicals to work. That means there’s no residue or waste, and that your pipes don’t get damaged from chemical use.

Water Stays Fresh

UV purifiers don’t use an integrated store tank. Water is constantly purified as it flows through the chamber. This means that your water is always fresh and doesn’t sit in a tank for hours. Still water can lead to contamination and can develop a stale taste.

Compact Design Works in Most Households

Thanks to their simple design and compact size, UV purifiers are easy to install in most households without needing to make significant changes to the plumbing system. You can even install bypass valves to make it easier to disconnect the purifier from your water supply when you need to do some maintenance.


There are very few negatives to UV purifiers, but one that is worth noting is their inability to expel particles. The full list of negatives includes:

Might Need Pre-Treatment to Reach Peak Effectiveness

UV water purifiers can’t remove particles from water, only kill microorganisms. But physical elements in the water can impact the light’s ability to reach the organisms, not to mention they can increase the frequency with which you need to clean the glass sleeve and replace it.

It Can Be Difficult to Check the Condition of the Device

UV light is invisible to our eyes, so you can’t determine whether the lamp is working or not just by looking at it. Furthermore, it’s not recommended to take out the glass sleeve and lamp often as you could scratch it or break it. This makes it so that determining if there’s an issue with the unit is tricky. However, a lot of modern units come with UV monitoring systems to let you know if the light’s potency has diminished.

Need Electricity to Work

UV water purifiers use UV light bulbs, so they need power to work. No power, no disinfection. Water will continue to flow, which is nice, but that can become a problem if you are unaware that the purifier is down and continue to use the water. Fortunately, a lot of UV systems include an alarm to let you know when the power goes out for the unit.

Water Will Retain its Taste and Smell

We mentioned this before in the positives, but it can also be a negative. If your water smells or tastes bad, the UV purifier can’t do anything about it. Bummer.


UV lamps emit heat, which gets absorbed by the water as it flows through the chamber. Most of the time, this is hardly noticeable. However, if the water hasn’t been used in a while, you might notice it being warmer the next time you open up a faucet.


UV water purifiers are one of the most effective and safest methods to purify water available to people.

They are easy to maintain, cost efficient and beyond disinfection they don’t affect your water in any way.

However, if you live in an area with water that has high hardness or other issues, you’ll need additional treatment systems to help.

Otherwise, they are a solid choice to make in terms of keeping your house water clean.

Further Reading


Meet Rory Mullan

Rory Mullan Rory has joined the Water Masterz team as a contributing writer. He has covered all sorts of topics in the last several years.

Outside of his writing work, Rory enjoys photographing the Irish landscape and making music!

Leave a Reply

Your email address will not be published. Required fields are marked *

9 − 5 =