Generally speaking, public health officials do test for water quality in areas that are “public swimming areas” i.e., beaches, recreational lakes, parks, etc… They also test drinking water sources. The water in other areas is not usually tested, (at least not regularly) unless there is a problem with contamination or someone reports a possible problem relating to the public health.
You could contact an environmental lab in your area that will test water quality (for a fee). They will advise you on the sampling protocol and requirements.
You can also go to your state’s Department of Environmental Protection or even the USGS website and search for surface waters information.
Preventing exposure is the optimum solution to this problem. When you get to the dive site, check it out. If it stinks, appears contaminated, has dead fish and dead animals in it, etc... then don’t dive in it.
As for public safety or working divers, “not diving” may not be an option. In this case dive dry with a full face mask system and follow dark water diving & de-con protocol.