The aim was to examine the hydration status of adults working in different jobs at the beginning and end of a shift and their reported water intake. One hundred and fifty-six subjects (89 males, 67 females) were recruited from workplaces within the local area (students, teachers, security, office, firefighters, catering). A urine sample was obtained at the start and end of the shift and was analyzed for osmolality (U_osm), specific gravity (USG), and sodium and potassium concentrations. Euhydration was considered U_osm <700 mOsmol/kg or USG <1.020. At the end of the shift, subjects were asked to report all water intake from beverages during the shift. Females had lower U_osm than males at the start (656 [range, 85-970] vs 738 [range, 164-1090] mOsmol/kg) and end (461 [range, 105-1014] vs 642 [range, 130-1056] mOsmol/kg; P < .05) of their working day. Fifty-two percent of individuals who appeared hypohydrated at the start of the shift were also hypohydrated at the end. Reported water intake from beverages was greater in males compared with females (1.2 [range, 0.0-3.3] vs 0.7 [range, 0.0-2.0] L, respectively; P < .0001). In conclusion, a large proportion of subjects exhibited urine values indicating hypohydration, and many remained in a state of hypohydration at the end of the shift.