Where wd I take creek water, to be tested for contamination.

State of Nebraska Public Health Environmental Lab 402-471-2122

Depends on the type of contamination. If you're checking for residual chlorine - I would assume the folks at the local water treatment plant could either do something like that for you - or - at least point you in the right direction. Typically though, with most water quality testing, you would want to test it at the source - with minimal time delay as temperature changes, mineral content and turbidity could affect the ability to get an accurate measurement.