Water Purification Question

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I have seen posts regarding the use of bleach here on Yourdans in the past. Can someone give me a good reference site as to the possible ill effects of too much bleach in your water stores ? Thanks in advance.

-- Robert (cybrgaze@hit.net), February 01, 2000


Here's a good place to start:


It's my understanding that if you let the water sit in an open container overnite, alot of the excess bleach will evaporate, so you can still salvage your supply. Anyone hear different? Please respond.

-- Hokie (Hokie_@hotmail.com), February 01, 2000.


I don't know about a site, but my chemist friend has researched the issue and told me that 8 to 10 drops per gallon is plenty in tap water. He said that "questionable" water needed 12 drops per gallon.


-- robert bright (roosterbos@go.com), February 01, 2000.

Too *much* bleach in the water? Maybe that explains albinos.

Sorry ... couldn't resist.

-- Steve Baxter (chicoqh@home.com), February 01, 2000.

The professional advice I've read for those going out into the bush or into third world countries is as follows:

8 drops of bleach per gallon if the water is clear. 16 drops of bleach per gallon if the water is cloudy.

It would require considerably more bleach than the above for water to become toxic. Furthermore, if the water is put in a wide-mouthed open container, most of the bleach will evaporate out in 24 hours, depending on the depth of the container.

-- elskon (elskon@bigfoot.com), February 01, 2000.


A. What you need

A normally active person needs to drink at least two quarts of
water each day. Hot environments and intense physical activity
can double that amount. Children, nursing mothers and ill people
will need more. Store one gallon of water per person per day (two
quarts for drinking, two quarts for food preparation/sanitation).
And don't forget your pets need clean drinking water as well.

B. Water Treatment (Courtesy of FEMA)

There are 3 main methods for treating water, boiling, disinfection
and distillation. For additional methods of purification, contact
your local Red Cross.

1. Boiling

Boiling is the safest method of purifying water. Bring the water to
a rolling boil for 10 minutes, keeping in mind that some water will
evaporate. Let the water cool before drinking or storing. Boiled
water will taste better if you put oxygen back into it by pouring it
back and forth between two containers. This will also improve the
taste of stored water.

2. Disinfection

Before storing your water, treat it with a preservative, such as
chlorine bleach, to prevent the growth of microorganisms. Use
liquid bleach that contains 5.25 percent sodium hypochlorite and
no soap. Some containers warn, "Not For Personal Use". You can
disregard these warnings only if the label states sodium
hypochlorite is the only active ingredient; and if you use only the
small quantities in these instructions.

Add four drops of bleach per quart of water (or two scant
teaspoons per 10 gallons), and stir. Seal your water containers
tightly, label them and store them in a cool, dark place.

3. Distillation

Distillation involves boiling water and then collecting the vapor that
condenses back to water. The condensed vapor will not include
salt and other impurities. To distill, fill a pot halfway with water. Tie
a cup to the handle on the pot's lid so that the cup will hang
right-side-up when the lid is upside-down (make sure the cup is
not dangling into the water) and boil the water for 20 minutes. The
water that drips from the lid into the cup is distilled. Store as

-- spider (spider0@usa.net), February 01, 2000.

Lot's of good answers, just not quite the right ones. I am curious as to the toxic effects of chlorination. I know that chlorine leaches after it sets and becomes carcinogen. I wish to learn about the effects of sodium hypochlorite on the human body.

Thanks for all the help folks.

-- Robert (cybrgaze@hit.net), February 01, 2000.

Buy a British Berkfield water filter. Gives you about 15 gals, a day of very pure water. The filters are good for 20- 60 gallons of feed water accordint to contamination. About $275.

-- goldenokie (garland@clnk.com), February 01, 2000.

That should be for 20,000 to 60,000 gallons of feed water.

-- Wilferd (WilferdW@aol.com), February 01, 2000.

---the appropriate levels of drops of bleach per gallon are here, but I would also like to add a ditto to the use of the berkfeld filter as the last step, after allowing the days worth of bleached water to "breathe". Remember, only room temp or cool water through any filters, not hot.

-- zog (zzoggy@yahoo.com), February 01, 2000.

Bleach in sufficient concentration is most likely to cause *direct irritation* to eyes, lungs, and other mucous membranes (nose, mouth, throat, etc). "Chemical burns." It is unlikely that bleach added to water for disinfection, even if someone misunderstood the directions and added say two times or even ten times the correct amount, would do much harm; very likely if so much was added that it was a direct problem, the water would taste awful and you wouldn't want to drink it.

In this regard, be careful when opening and/or pouring bleach; the *fumes* can certainly cause serious breathing problems. Be especially careful if you have stockpiled concentrated bleach (typically 70%) to use for making a stock solution of "household bleach" (5.25%) for other uses, including for water. The concentrated stuff is quite nasty and IMHO you *must* use gloves and mask and have excellent ventilation when handling it.

As far as longer-term effects of bleach, there are some concerns about chlorine compounds causing cancer, but the effect is likely very small at most. (I don't want to get into an extended discussion n this possible chronic effect, please; it's not my speciality! FWIW I can tell you that I did't worry about it when I used to drink municipal water--but I am now on a private well, thank you).

The above posts are quite correct that excess chlorine will dissipate if the water is allowed to sit in an open container. You can also improve taste by pouring the water back and forth between two clean containers just before drinking it, to "aerate" the water.

--Andre in southcentral Pennsylvania public health physician

-- Andre Weltman (aweltman@health.state.pa.us), February 01, 2000.

I talked to a guy at the CDC in Atlanta last year and he said there are at present certain strains of bacteria ( giardia, cryptosporidium) that are resistant to convential chlorine disinfectant. You really ought to get a good filter (.2 microns)...the Berkfeld or an Aqua Rain. For travel, ceramics could crack so instead get the seychelle Bottoms up type, a sports bottle with a .2 micron filter at the top. You can still pre treat with bleach but don't rely exclusively on it.

-- lyn (lynhettler@hotmail.com), February 01, 2000.

Sodium hypochlorite on the human body creates a burning sensation.

Helpful hint:

If you are ever on the top of Everest, frost-bitten and near death, simply pour a few ounces all over your skin. In a matter of seconds, you will imagine yourself in the cheapest barrio of Hell, in a shack on fire, with the volunteer firefighters spraying your pad with napalm, dispersed by gusty hot winds during a record-breaking heatwave, compounded by the drought.

-- Joseph Almond (sa2000@webtv.net), February 01, 2000.

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