29 C.F.R. § 785.12 : Labor — REGULATIONS RELATING TO LABOR — WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR — STATEMENTS OF GENERAL POLICY OR INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS — HOURS WORKED — APPLICATION OF PRINCIPLES —EMPLOYEES "SUFFERED OR PERMITTED" TO WORK — Work performed away from the premises or job site
The rule is also applicable to work performed away from the premises or the job site, or even at home. If the employer knows or has reason to believe that the work is being performed, he must count the time as hours worked.