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Clear Nalgene or other water bottles + natural UV
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John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
Clear Nalgene or other water bottles + natural UV on 03/25/2013 13:47:11 MDT Print View

If UV light can purify water for drinking using a SteriPen for instance, could a clear water bottle achieve the same results?


I was watching a video review of the SteriPen Adventurer and had a...

Hmmmmm! the old Sun Tea idea came to mind.

What opinions or experience does anyone have on this idea?

Party On,


Jan S
It does work on 03/25/2013 13:53:04 MDT Print View

As far as I know sun works too. Exposure time has to be considerably longer though and ... well ... the sun should actually be out. Pacific North West in winter is probably not working so well. Australian desert in the summer should work well ;)

Edit: Right, the bottles itself filter UV light. Hadn't thought of that.

Edited by karl-ton on 03/25/2013 14:10:52 MDT.

Ian B.

Locale: PNW
Doubt it on 03/25/2013 13:56:01 MDT Print View

By no means is this a definitive answer but my understanding is that short wave UV light cannot pass through glass and most plastics. The steripen lamp is made out of quartz for this very reason.

Smart people?

steven franchuk
Re: Clear Nalgene or other water bottles + natural UV on 03/25/2013 14:02:54 MDT Print View

Most plastics block UV light. Very little UV would make it to the water. clean lake water is exposed to UV for days, yet experts still advise treating the water.

Max Dilthey
(mdilthey) - M

Not so Fast! on 03/25/2013 14:14:46 MDT Print View

This method is approved by the World Health Organization for treating household water. Here's a link:

For the lazy, here's a link to some 30+ studies that confirm light filtering through clear bottles (like PET plastic) will disinfect water a significant amount over 6 hours:

Edit: Here's some more info.

-Even extreme levels of fecal matter (100,000 E. Coli per 100ml) are rendered harmless by UV exposure using the SODIS method (Solar Disinfection).
-A bottle 3 liters or smaller must be placed on its side for 6 hours in direct sunlight to be rendered harmless.
-Only clear bottles will correctly allow UV radiation in.
-Some bacteria grows with sunlight, but this is harmless bacteria.

Edited by mdilthey on 03/25/2013 14:24:51 MDT.

Hamish McHamish
(El_Canyon) - M

Locale: USA
_ on 03/25/2013 14:38:38 MDT Print View

Max beat me to it. Google "SODIS". There are caveats. Due to required exposure time even in ideal environments I would consider SODIS an emergency/survival tactic. Not super useful for the typical BPL hiker but it could be a lifesaver if you're on an international trek near the equator and run into water treatment problems.

Ian B.

Locale: PNW
Interesting on 03/25/2013 14:40:45 MDT Print View

Another thread on this topic.

Reading through the link from above, it seems that 6ish hours are required. Probably not practical for backpacking but great for third world countries though. I previously understood that UVC was the requirement for sterilizing pathogens but there's obviously more to the story than that. Seems temperature plays into the SODIS process as well.

Interesting article nonetheless.

Edit: James covered this while I was typing.

Edited by IDBLOOM on 03/25/2013 14:42:36 MDT.

Max Dilthey
(mdilthey) - M

Speed! on 03/25/2013 15:37:20 MDT Print View

It's okay, guys. You were up against a journalist ;)

Ian B.

Locale: PNW
Max on 03/25/2013 15:50:30 MDT Print View

Gracious personality and a journalist to boot! In my effort to become all that is man, would it be okay if I follow you around for a week and take notes?

Colin Krusor

Locale: Northwest US
SODIS on 03/25/2013 16:45:27 MDT Print View

I went to a global health conference a while ago and attended a talk about SODIS implementation in Africa. A major obstacle to acceptance by people living in African villages is stigma and aesthetics. In areas where waterborne parasites cause high mortality among children, people who adopt the SODIS method for water disinfection are stigmatized and ridiculed by their neighbors. People consider them gullible for believing that the water is unsafe just because some health worker told them so. They also don't like the way the bottles look, lined up on the roof.

Anyway, I would have to agree with the other posters: it doesn't seem practical for backpacking except on perfectly clear days at high elevation or low latitude. And the bottle(s) need to be thin-walled PET (not thick-walled lexan Nalgene) and strapped on the pack in full sun (no part shaded).

Nathan Watts
(7sport) - MLife
A vs C on 03/25/2013 16:57:32 MDT Print View

A steripen uses UV-C
Sunlight that penetrates the atmosphere is UV-A

Both are effective at treating your water.

Your bottle will block UV-C, which is why the Steripen is safe to use.
UV-A from the sun will penetrate the bottle, which is why you can treat water in a bottle with this method.

Hope I didn't cross up the letter designations too badly

Max Dilthey
(mdilthey) - M

@Ian on 03/25/2013 19:48:59 MDT Print View

Ian, I was just joking!

Ian B.

Locale: PNW
Relax toots! on 03/25/2013 20:00:20 MDT Print View

So was I :)

Jason Elsworth
(jephoto) - M

Locale: New Zealand
Clear Nalgene or other water bottles + natural UV on 03/25/2013 20:41:54 MDT Print View

Gracious personality and a journalist to boot! In my effort to become all that is man, would it be okay if I follow you around for a week and take notes?

LOL - someone had to say it.

Paul Kelly
(lympit) - MLife
lympit on 03/25/2013 20:45:32 MDT Print View

boys let the light shine - it will cleanse all