In Essex County grand jury today returned a 141-count indictment against Newark Mayor Kenneth A. Gibson, City Council President Earl Harris and Michael Bontempo, a former security supervisor for the city.

The three officials are charged with "theft by deception," neglect of duty and misconduct in office from June, 1974, to September, 1981. They allegedly put Bontempo, an elderly former council member and 28-year city police veteran, on the payroll in a "no show" job at which he earned $115,000.

Essex County Prosecutor George Schneider said today that Gibson and Harris gave Bontempo a $24,000-a-year job supervising security for the city's water system.

But when vandals last summer opened unlocked valves in water mains at the Pequannock watershed, a western New Jersey pumping station that supplies much of the city's water, Bontempo was in Florida. The vandalism shut down the city's water supply for days and caused $2 million damage.

"Bontempo was nowhere to be found," Schneider said. He said that although Gibson and Harris did not receive any money in the alleged conspiracy they were aware Bontempo had moved to Florida.

At a press conference today in Newark City Hall, Gibson, surrounded by 14 Newark clergymen and scores of cheering supporters, denied any wrongdoing.

"I'd hire Michael Bontempo again tomorrow," Gibson, New Jersey's top black elected official, said. "Former city officials make excellent city employes."

When a reporter asked if the mayor would resign, he was shouted down by supporters.