The Ventura County Board of Supervisors on Tuesday urged a water district serving more than 60,000 people and hundreds of farms to declare a drought emergency. Supervisor Steve Bennett said the declaration should be made promptly to warn residents about the seriousness of the situation in the western Ventura County area served by the Casitas Municipal Water District. “It is critical that those who rely on (the district’s) water realize the dire nature of this drought and have the opportunity to take any steps they possibly can to conserve further and stretch the length of time water is available,” Bennett wrote in a letter to the board.