This isn't necessarily true, while it's nice to check i prepare these reports for a living. The only information that has to be included are contaminates that are tested and present in the source. For instance co2 isn't something normally tested so it could be present and just not tested. Another example is if you test for copper the mcl is 1.3 mg/L most labs will test a threshold of .1 mg/L if the threshold isn't met it won't be shown on the report. This doesn't mean it's a true 0.00 as <0.09 is considered safe to drink but you probably don't want that much copper in a tank. Anyway, just an explanation of how these reports work.
