Second, you must have worked for the employer for at least 1250 hours in the 12 months before you take leave. That works out to an average of about 24 hours per week over the course of a year. Lastly, you must work at a location where the employer has at least 50 employees within 75 miles of your worksite.n order to take FMLA leave, you must first work for a covered employer. Generally, private employers with at least 50 employees are covered by the law. Private employers with fewer than 50 employees are not covered by the FMLA, but may be covered by state family and medical leave laws.