There are many reasons why it is a good idea to use a drug screening process to ensure that any and all applicants to your workplace maintain a certain level of professionalism both in and outside the workplace. After all, if you are going to be relying on them in a professional capacity there are some things that you do need to know about them before they start working for your company. Drug testing is conducted by many health care clinics and is an easy process to set up if you so wish. Here are a few of the more obvious reasons that highlight why employers use drug screening processes.
If you are applying for a role in a business that values its privacy and secrecy, such as those that operate with a lot of clients' money or perhaps for a governmental role, then it is important you do not have any vices or temptations that could cause you to mess up at work. When people make mistakes in these roles millions of dollars can be lost or lives could be threatened (in the case of the governmental agency job), and so eliminating the option of any drug abuse is well within your rights as an employer.
On perhaps the opposite side of the spectrum, many religious organizations can also request drug testing to ensure that all applicants meet with their more strict ethical and lifestyle standards. After all, if you are going to be a representative of that church, temple, or mosque then it makes sense that you follow some of their core beliefs. For the vast majority of applicants in this area, drug use is not an issue, but the practice of drug testing is still used just for the peace of mind of your employer.
Sometimes when you are hired, the company doing the hiring is making a long-term commitment with you and may invest thousands in your training, relocation, and housing expenses. For these roles, your employer will want a few assurances that their investment is not going to blow up in their face or that there will be any unforeseen issues that they may face in the near future. Drug testing is therefore not so much a question about your lifestyle but just about whether you are a good investment for the company to make, and they do not hold any judgment or moral view about what you do in your personal life.