Dispersion of E coli, Possible?

[cloudnine]

I am about to start my experiment.
My work is to analyse the quality of water from the domestic water supplies (eg. of a township). I think I have to use Eshcerichia coli as an indicator.
In this work, I think I should analyse the plasmids of E.coli. And so, I think I will know how these bacteria are dispersed in this very region. Once knowing this, I will be some way to make the treatment if certain disease outbreak from water is occured.
Is my thoughts are possible? I search on the internet about similar works done to be referenced. But I couldn't find them, may be I don't know where to find.
Please let me know some information and advices for my work. I am little bit confused with how to collect the data? How can we know the dispersion only by this experiment? What are the types of plasmids I am about to find?
Please reply me. I am looking forward to your reply. Thank you in advance for your time.

cloudnine