Are UV Light Bottles Safe?

I recently got given a HydroCap UV Filter Lid for my Hydro Flask bottle and I've been using it to treat both tap water as well as river water when I'm out on my bush walks.

But I'll be honest with you, one of my biggest concerns with this product was whether or not UV light bottles are safe, if I might be exposed to the UV rays increasing my chances of cancer and if the UV sterilization was safe and actually worked.

I had a few major questions:

  1. How would I know if the UV filtration actually worked and killed bacteria, protozoa and viruses like it says it does?
  2. Would the UV radiation somehow make the water unsafe to drink? (eg. Radioactive)
  3. Would the UV radiation pass through the bottle potentially exposing me and my skin to harmful UV rays?

Thankfully after doing a bit of research I quickly discovered that no, the HydroCap and other UV light water bottles don't seem to pose any health threats to me or my family.

UV Light Bottles are safe to use. The UV light effectively kills 99.9%+ of bacteria, protozoa and viruses in the water and the UV light doesn't stay in the water or contaminate it in any way. UV rays also don't pass through opaque water bottles so you won't be exposed to excess UV rays when using them.

In this article we'll look in more detail as to the safety of UV light water bottles so you can decide for yourself whether or not you feel confident using them and if you want to buy one yourself.

How Effective Are UV Water Bottles? Do UV Water Bottles ACTUALLY Work?

If I'm going to be filling up my water bottle from the river and drinking it I want to be 100% confident it isn't going to make me sick.

So it was normal for first concern with my new UV light lid to be whether or not it actually worked. I don't want to buy this and end up unknowingly drinking contaminated water.

I can't see the UV lights in action as they are hidden inside my stainless steel water bottle while they are active and there is no discernible difference in the appearance of the water before and after treatment. So how can I know whether or not it's worked?

UV light water bottles that produce UVC light are extremely effective at killing bacteria, protozoa and viruses. They have been tested by 3rd parties to show they deactivate up to 99.9775% of e-coli after 1 minute and 99.9999% after 3 minutes.

But rather than just taking the surface level marketing of these products at face value I wanted to do a bit more research into the effectiveness of these water bottles and of UV light water treatment in general.

The HydroCap (which I own) uses the same technology as the CrazyCap (same company different product) and below you can see a graph of just how effective the CrazyCap was as killing e.coli bacteria.

A similar study was done on the HydroCap to test it's effectiveness against e.coli and below you can see the final report for this test:

Seeing this report and the results

Similar studies have been done on the LARQ water bottle which uses similar technology to the HydroCap in order to kill bacteria, protozoa and viruses in water.

You can see LARQ's studies linked below:

Videos On The Effectiveness Of UV Light

While not a direct look at the effectiveness of UV light water bottles the videos below do show people doing experiments using UV light on surfaces to kill bacteria colonies.

The differences between the untreated surfaces and the UV light treated surfaces is remarkable.

Also the differences between a 1 minute treatment and a 3-5 minute treatment is also extremely interesting. Check them out below to see just how effective UVC light is at killing micro organisms.

All in all these studies plus the videos below give me the personal confidence that YES – UV light water bottles are extremely effective at rendering bacteria, protozoa and viruses inert and unable to multiply and make you sick.

See the latest price of the HydroCap at Amazon
(or compare to the latest price of the HydroCap at

Is UV Purified Water Safe To Drink?

One of the jokes my friend made when I first got a UV light for my water bottle was that my water was now radioactive and she was nervous to drink it.

If you don't know much about UV water treatment then this is a fair concern to have. After all we all know UV radiation is dangerous and cause skin cancer. So can it potentially cause our water to not be safe to drink?

UV purified water will be 99.99% free of active bacteria, protozoa and viruses if treated correctly. However, UV light does not filter out salts, minerals, micro plastics or harmful chemicals from the water so it's safety also depends on the quality of the water.

However, if you're drinking for a relatively clean water source (like a free flowing river) with no known chemical wastes in it then treating it with UV light for 3 minutes or more should make the water safe to drink.

The UV light does not hang around after treatment is complete and is absorbed into the walls of the water bottle. So you're not getting exposed to extra UV radiation by drinking water previously treated with UV light.

In fact, chances are you're already drinking water treated with UV light.

UV radiation treatment is an extremely common way to treat municipal water supplies. This means chances are you are already drinking water that has been treated with UV rays and have been for years and you've never questioned it.

In fact, according to the Water Research Center – UV treatment has been used as far back as the early 1900's and there are over 2,000 UV water treatment plants in Europe.

UV treatment doesn't inject any potentially harmful chemicals into the water and is deemed by many with much better credentials than me to be safe.

Do UV Light Bottles Expose You To Harmful Radiation

My last biggest concern when it came to the safety of my UV light water bottle was whether or not the UV rays would go through my water bottle and expose me and my kids to excess radiation that I would obviously prefer to avoid.

It only took a little bit of research to discover that UV lights really struggle to get through metal. In fact, UV rays are blocked by almost anything that blocks visible light. This is why UV light water bottles only work with clear transparent water and don't work with murky water.

So the chance of much if any of the UV light getting through the bottle and onto my skin is EXTREMELY small.

Also, HydroCap has a safety feature that turns off the UV lights if it detects that the lid is not on the bottle. It'll work for maybe 1-2 seconds outside of the bottle and will then switch off.

I have to tell my kids not to ever activate it when it not in the bottle, but other than that I feel completely safe using this product.

Are HydroCap Bottles Safe?

The HydroCap shoots UV lights into your water bottle to kill bacteria, protozoa and viruses. But is the HydroCap lid safe to use?

The HydroCap lid is safe to use. It kills 99.9%+ of bacteria, protozoa and viruses and does not contaminate water nor do the UV rays pass through the bottles which would expose you to UV radiation. There is a safety feature so the UV lights will not stay activated if the lid is not on your water bottle.

The HydroCap uses LED UV lights which do not contain mercury and do not emit ozone when used.

So all in all the HydroCap seems to be an extremely safe and easy way to clean the water in your water bottle and I personally feel confident using it to drink clean water from rivers and streams in the national parks I visit when I go waterfall hunting.

It's also great value for money as it is backed by a 10 year warranty and doesn't get clogged or need to be replaced regularly like membrane filters do.

See the latest price of the HydroCap at Amazon
(or compare to the latest price of the HydroCap at

Are LARQ Bottles Safe?

LARQ bottles shoot UV lights down into your water bottle to effectively kill bacteria, protozoa and viruses, keeping your bottle extremely clean. But are LARQ bottles safe?

LARQ bottles are safe to use. They kill 99.9%+ of bacteria, protozoa and viruses and does not contaminate water nor do the UV rays pass through the bottles which would expose you to UV radiation.

LARQ bottles have been tested by 3rd party labs to work extremely effectively at rendering microorganisms inert so they cannot replicate and cause sickness or disease.

The LARQ uses LED UV lights which do not contain mercury and do not emit ozone.

See the latest price of LARQ water bottles at Amazon

How Do UV Water Bottles Work To Kill Bacteria, Viruses and Protozoa?

If you're like me and enjoy understanding the why behind how something happens then the video below showing exactly how UV light causes these microorganisms to explode is absolutely fascinating.