How can I measure how much bacteria growth occurs in reused water bottles - science project query (Nov/22/2008 )

I am currently doing a science project in which I have to measure the amount of bacteria growth in reused water bottles. I am not quite sure as to how to conduct the experiment.
Advice on how the problem should be stated, the materials needed, and step by step instructions on how to perform the experiment are greatly appreciated. Please and thanks!

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Well, here's some basic background you'll need to know before you get started.

http://student.ccbcmd.edu/courses/bio141/l.../lab4/lab4.html

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