Preventing Bottled Water Contamination
by Ron Kurtus (revised 27 February 2012)
Many people purchase large bottles of water for their home or office, because it is better to drink. Often the bottle may be dirty on the outside, possibly contaminating the water. Slime may also grow in the water cooler reservoir. Also, sometimes the water is not the quality you would expect.
Questions you may have include:
- How can the outside of the bottle contaminate your drinking water?
- Where does slime come from?
- What are problems with water quality?
This lesson will answer those questions. Health Disclaimer
Although the insides of the large plastic bottles used to supply bottled water to you are assumed to be thoroughly cleaned, there are no requirements on cleaning the outside of the bottle—especially the top that comes in contact with your drinking water.
Dirt dissolves into water
When the bottle is tipped on its end over the reservoir, about 10 square inches of the bottle top surface is in contact with your water. Any dirt on the top will fall or dissolve into your drinking water.
Wash top of bottle
Take a wet paper towel and wipe off the top area of a typical bottle, and you will see the amazing amount of dirt that has collected on the surface. When the bottle is put on your reservoir, that dirt will go into your drinking water.
If a service puts the bottle on for you, you might still check to see how clean the top area is and perhaps ask to clean them off before the service man puts the bottle on the reservoir.
Slime in reservoir
Bottled water is not chlorinated, so it does not kill tiny organisms that may grow in water. Even if you start off with a very clean water cooler reservoir, after several months green slime may collect on the insides. It isn't a bad idea to occasionally check the insides when the water is almost gone.
Don't use soap to clean the inside of your reservoir. Soap is for cutting grease, and that is not the problem. Also, the residue will linger for a while until it is all flushed out.
Rather, empty the reservoir and scrape of any slime with a clean paper or cloth towel. You can use a very dilute bleach solution, if you then rinse it out thoroughly.
Question of water quality
Some bottled water companies have simply provided tap water in their bottles. Others claim to purify the water themselves. It is good to make sure you are getting the quality of water for which you are paying.
Several years ago there was a big flap when petroleum contamination was found in the expensive Perrier bottled water. They claim to have solved the problem, although their sales dropped as a result of the negative publicity.
Distilled water should be pure. Regular bottled water has some minerals in it, which enhances the taste, but if you have very hard water, the minerals collected in the coffee-maker can clog up the works.
The top of a bottle of water may be quite dirty and should be cleaned before using. The reservoir should be occasionally cleaned of any slime growing on the surfaces. Make sure you get the quality of water you are paying for.
Help others maintain their health
Resources and references
Bottled Water -Pure Drink or Pure Hype? - Natural Resources Defense Council
Many Methods of Water Purification - Article from Berkley Filters Co.
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