Just make sure you collect samples for bacteriological and chemical analysis periodically. If you haven't already, get either a chlorine analyzer or some test strips to make sure you have sufficient chlorine residual at the outlet of the contact tank. A raw water test is helpful because some pathogens require stronger doses and/or longer contact times.
I prefer ozone to chlorine because it oxidizes the hell out of everything. Its downside is that it does not leave behind a measurable residual.