South Bay Irrigation District was formed in 1951 to represent citizens of Bonita and the western portions of the city of Chula Vista. Five elected Directors represent five geographic areas of the district.
In 1977, South Bay Irrigation District and the City of National City formed a joint powers public water agency, named Sweetwater Authority. Sweetwater Authority manages and operates the water system, providing water to National City, Bonita and western portions of Chula Vista, California.
Sweetwater Authority's governing board, or board of directors, is composed of seven members. Five directors are elected by division by the citizens of the South Bay Irrigation District. Two directors are appointed by the Mayor of National City, subject to City Council confirmation.