It’s important to conduct DOT drug testing. While you want to make sure that it is getting done, it is actually better to do it sporadically as opposed to drainagenwaterproofing on a set schedule. You can then be sure that its done, but in such a way that employees wont know when they will be called for the test. Keep Your Drivers Guessing The last thing you want is for your employees to know exactly when they are going to be drug tested. The idea is for it to be random that they never know its going to happ.