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How Much Bleach for Water Treatment
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John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
How Much Bleach for Water Treatment on 05/10/2011 09:39:18 MDT Print View

If using bleach for water treatment, how much bleach should one carry for say a week's trip.

Please allow for the fact that I am prone to drinking quite a bit of water in the warmer temperatures.

Also would you please share your storage and dispensing methods. Please include pictures whenever possible.

Party On,


Edited by Newton on 05/10/2011 09:40:06 MDT.

John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
Re: How Much Bleach for Water Treatment on 05/25/2011 04:38:10 MDT Print View


Party On,


Ken Charpie
(kencharpie) - MLife

Locale: Western Oregon
The State of Washington knows on 05/25/2011 05:38:06 MDT Print View

I'm not sure that many members of this site use bleach for treating their drinking water...
The state of Washington has some guidelines for emergency usage (with specific instructions and dosage guides) here:

John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
Re: Bleach for Water Treatment on 05/25/2011 06:36:08 MDT Print View

Thanks for the link Ken.

"I'm not sure that many members of this site use bleach for treating their drinking water..."

I have seen in other threads where Ben2world has spoken about using bleach for treating drinking water. But you are correct in that I have not read of many others using this method.

I guess I'll have to "guesstimate" by multipling the number of drops per liter by the number of liters of water that I may possibly drink in a week's time. Then I could just double that for my two week trip.

I'm not sold on the idea but the short wait time for drinkable water using bleach has me interested.

Thanks again.

Party On,


Walter Carrington
(Snowleopard) - M

Locale: Mass.
bleach water treatment. on 05/25/2011 07:54:51 MDT Print View

This is from memory, so may not be completely accurate.
Bleach is not great for water treatment.
Household bleach is somewhat unstable; I don't know how long it'll remain active on trail.
It's operation is affected by pH, mineral content, temperature; city water systems have all this controlled, but you won't.
Not effective for giardia and cryptosporidium.
Worcester, Mass used to use chlorine in it's city water and had cryptosporidium in the city water. I think they switched to chlorine dioxide (like aquamira).
Bleach is effective on viruses, but in the USA viruses are less likely than bacterial problems or giardia or crypto.

From my reading, I'd say that:
Boiling is best but takes a lot of fuel; probably the best solution in midwinter.

Aquamira tablets are OK, but take a long time to kill giardia or crypto.

Better would be a good filter that removes crypto, giardia and bacteria and add bleach anyplace I was worried about viruses. Sawyer makes a good filter for bacteria; there are threads on MYOG gravity filter using the Sawyer 0.1 micron filter.

I just bought a steripen UV device and will use that, though the thought of drinking deactivated bacteria and protozoa creeps me out a bit (completely irrational).

Joe Bancks

Locale: Midwest
Just a thought on 05/25/2011 19:42:01 MDT Print View

on why so few responses:


it's like that packrafting device that is not a PFD. emphatically not a PFD.

Nothing else to add, sorry.

John S.
(jshann) - F
Re: Just a thought on 05/25/2011 20:12:15 MDT Print View

Fill up a one ounce bottle.

nanook ofthenorth
(nanookofthenorth) - MLife
... on 05/25/2011 20:51:39 MDT Print View

I used it growing up canoe tripping. Nothing too fancy, we used 2 drops per 1L lake water, if it was cloudy with organics, more. 30min at room temp/summer and your good to go. Never gotten sick from bad water in Ontario with this, b/c I'm often in parks or really far north paddling have been drinking water straight from the lakes most of the time. Never had an issue there either.
Hard to say, my experience has been good with the stuff but YMMV. Thinking about Aquamira - but kinda put off by the price. Sounds like its more reliable though.

Link .
(annapurna) - MLife
Re: How Much Bleach for Water Treatment on 06/02/2011 11:37:51 MDT Print View


Edited by annapurna on 06/03/2011 10:06:56 MDT.

Michael Ray
(topshot) - MLife

Locale: Midwest
Re: How Much Bleach for Water Treatment on 06/02/2011 11:56:40 MDT Print View

I use 4 drops per liter normally (I believe 2 is EPA rec for clear water). I carry mine in a Visine bottle. For 11 days I may go through 1/3 oz. While I originally thought it would take care of crypto with a longer wait time like ClO2, I've since learned that isn't the case. Given that, I may switch to using tablets at some point. Some people, including Ryan Jordan apparently, incorrectly pre-mix the liquids and the whole liquid mixing seems such a pain despite the lower overall cost.

I also carry a Frontier Pro filter but have never used it. I suppose I actually should just start using it and then I can keep using dirt cheap bleach AND not worry about crypto/giardia.

John Donewar
(Newton) - MLife

Locale: Southeastern Louisiana
Re: Re: How Much Bleach for Water Treatment on 06/02/2011 15:55:23 MDT Print View

Hi Michael,

The info below was copied and pasted from the following website.

"WARNING: Chlorine or iodine will not reliably kill Giardia and Cryptosporidium. At colder temperatures, doubling or tripling the wait time will improve your chances. Boiling or chlorine dioxide tablets and good water filters are more reliable".

"I also carry a Frontier Pro filter but have never used it. I suppose I actually should just start using it and then I can keep using dirt cheap bleach AND not worry about crypto/giardia".

I also carry the Frontier Pro along with Katadyn Micropur tablets. I must admit that I find the FP slow as far as the flow rate and do not always use it. I try to rotate my "treated" and "using" water bottles to allow the tabs time to do their work on the Giardia and Crypto.

Micropur recommends a treatment time of 4 hours to guard against G & C.

Using the bleach info from above with Clorox's recommended wait time of 30 minutes, if I double or triple the wait time as suggested my "being treated water bottle" is at most only 90 minutes away from being usable.

Below is the link to the Clorox website.

I do realize that Clorox makes no claim to their effectiveness against Giardia and Crypto.

I'll more than likely stick with the tablets and possibly the FP plus the tablets. I was hoping for a less expensive and time consuming method. Thank you for sharing your knowledge and experience in this area. I do appreciate it.

Party On,


Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: How Much Bleach for Water Treatment on 06/02/2011 16:01:41 MDT Print View

Part of the problem with chlorine-based bleach has to do with benign impurities in the water. If there is a lot of decaying leaf matter in the upstream water, then you have various nitrogen compounds getting to your chlorine. You might not get the effectiveness from the chlorine as a result. A public water test lab would see this and make suitable adjustments. However, very few of us bring the whole lab with us out on the trail, so there is more guesswork.


Brian Waspi
(ClearWaterOutdoor) - F

Locale: Midwest
Careful With This on 06/02/2011 16:21:06 MDT Print View

Chlorine and Iodine as purification are always a function of TIME and QUANTITY. There are published safe standards from the EPA on what's "safe" in drinking water by PPM (parts per million) Here's a link: You definitely don't want to be overdosing with either of these while in the backcountry, it's dangerous and easy new to do.

Unfortunately you're not going to find an "exact" answer to this because using it for purification depends a lot on the source of the water you're purifying, temperature, how long you let it sit, etc. I've carried iodine with me more as a safety net in the event my water purifier breaks on me, but really prefer not to use it; especially since iodine and bleach can lose their effectiveness if stored to long and/or exposed to air for to long. There are two awesome alternatives available now that were not in the past. Here's a couple links to purifiers that are uber light weight. Again, always carry a secondary method like bleach or iodine but I wouldn't use it as my primary and only means for any length of time.

MSR MIOX Purifier -

Steripen Classic -

Kevin Sweere
(sweerek) - F
kudos to Brian Waspi on 08/27/2015 17:00:03 MDT Print View

After a few hours surfing the web for reputable sources, I CONCUR with Brian Waspi. Its the amount of free chlorine in the water and how much of it reacts (= time * reaction speed) is what determines how many nasties will be chemically busted-up.

Determining the quantity to use is difficult given amount of NaClO in water ratios vary across bleach brands, age and sun decrease the amounts, and assorted things about the water affect the effective chlorine level. For example, to treat the toughest nasties in water, Portable Aqua Pure* (salt + water + electricity = bleach) include chlorine test strips to insure you've enough chlorine (and you still need to wait ~3 hours)

Having used bleach as a kids decades ago, there's also a taste issues. Some plain bleaches taste horrid so I stuck w/ plain Clorox.

Another reason to carry bleach is to sanitize dishes and such in larger groups. With Boy Scouts, we use a capful of bleach to sanitize dishes after the wash and rinse cycles.

I own and teach Scouts about a dozen different water treatment methods, but I carry a gravity filter, Aqua Mira drops, and a few tablets in foil packets.

* Btw, the device's manual + is pretty good on the chemistry aspect

Edited by sweerek on 08/27/2015 17:02:51 MDT.