Set objShell = WScript.CreateObject("WScript.Shell")

' set the initial interval to 30 minutes (in milliseconds)
interval = 1800000 

' loop indefinitely
While True 
  ' wait for the interval
  WScript.Sleep(interval)

  ' display the reminder message
  objShell.Popup "It's time to drink some water!", 5, "Water Reminder"
  
Wend