Drug screen for pre-employment last thurs, I am totally clean and havent used ANY drug in over a year. But it was a hot day and I was drinking the previous night, so I drank about 80 fl oz of water over the course of several hours prior to my test. Test came back dilute and my employment WAS DENIED, no second test, no second chance, no dice. After doing some searches to determine if that was something I should contact the Better Business Bureau about I found Quite a few sites that state that Federal law, as well as most non governmental employers (aka private employers) have the policy that a dilute test either pos, neg, false pos or false neg are to be treated as Positive. Period. Here is one site that lays down the letter of the law in that regard Regulations - Federal Motor Carrier Safety Administration

So the moral of the story is even if you are drug free, even if you are trying to beat a test, dilute samples are bad joo joo. And damn you to hell if you feel like being healthy and hydrated.