SAN DIEGO -- Proposition S, a $2.1 billion San Diego Unified School District bond issue, was one of seven local school district bond measures approved by voters, election returns showed Wednesday.

Proposition S is a follow-up to Proposition MM, which was overwhelmingly approved 10 years ago, said Katherine Nakamura, president of the Board of Education in San Diego.

With 100 percent of precincts reporting, Prop. S garnered 68.16 percent yes votes compared to 31.84 percent no votes. It required 55 percent of the vote for approval.

District officials told school board members in July that despite the improvements from MM, the district's buildings remain in poor condition. District facilities are 39 years old, on average.

Opponents argued that property-owners will be saddled with the tax liability while the $1.5 billion of MM bonds are still being paid off.

Prop. S funds are to go to fix heating and air conditioning systems, make facilities more accessible to disabled students, and upgrading technology in classrooms.

In other bond measures, Southwestern Community College in Chula Vista got the backing of voters for Proposition R, a $389 million bond issue, and Grossmont Union High School District got the backing of voters for Proposition U, a $417 million bond issue.

Bond measures also passed in school districts in Escondido, Lakeside, Lemon Grove and the South Bay.