13 months? I think first indictments were just shy of 3 months or so.
On June 19, 1972, it was publicly revealed that one of the Watergate burglars was a Republican Party security aide.
On March 1, 1974, a grand jury in Washington, D.C., indicted several former aides of President Nixon, who became known as the "Watergate Seven": Haldeman, Ehrlichman, Mitchell, Charles Colson, Gordon C. Strachan, Robert Mardian and Kenneth Parkinson, for conspiring to hinder the Watergate investigation.
That would be 22 months.