Whether a bus driver, a nurse, an athlete, or mandated for court-ordered purposes, there are many reasons an individual would need to take a drug test to know whether or not cannabis, or its main component, THC, is present in their system. But with so many conflicting reports, it’s hard to know exactly how long weed stays in your system, and how long it will take to pass a drug test and get a negative result.   Buckle up, because we’re going to dive into the nitty-gritty of all the factors that contribute to how long cannabis stays in your system. And with so many different testing methods, we’ll also take a look at how your usage levels and other factors affect specific testing results.   Almost half of all adults in the USA say they have tried cannabis at least once, and nearly 30% consume on a regular basis, according to a Gallup poll Even with such widespread use, many employers do not allow their employees to test positive for weed, especially in industries such as transportation–think bus drivers and airline pilots, and healthcare–think nurses and hospital workers. Many court-ordered drug treatment programs also regularly test for weed, in addition to other substances, so knowing how long THC stays in your system is important if you choose to consume.