The swearing-in ceremony was performed at the Executive Council Chambers of Government House in Port Harcourt on Wednesday.
The chairmen were earlier screened and confirmed by the Speaker Oko-Jumbo-led Assembly.
The governor had earlier sent sent the list of nominated caretaker committee chairmen to the House of Assembly led by Speaker Victor Oko-Jumbo.
The Oko-Jumbo led lawmakers scheduled Wednesday to screen and confirm the nominees.
A statement by the Clerk of the Oko-Jumbo-led House invited the nominees to appear before it at 8am with 12 sets of their credentials, original and photocopies.
The lawmakers said they were acting in line with Section 9 (5) of the Rivers State Local Government Law.
However, following their successful screening by the lawmakers, Governor Fubara proceeded to inaugurate them.
While swearing in the Caretaker Chairmen, Fubara mandated the auditor general of the state to begin the audit of the accounts of the 23 Local Government Areas for the past three years.
The governor said the measure is intended to serve as a check for the incoming officials.
He urged the caretaker chairmen not to see themselves as superheroes, but to protect the interests of their people, and demonstrate that the government made the right choice in appointing them.
He emphasised that the current events are a product of democracy.
Fubara explained that the fight against tenure extension is not just about the state, but the entire country, as allowing it in one state could lead to it being replicated nationwide.
He pointed out that Rivers State was not doing anything unusual, as most states in the country are also run by caretaker committees.
He, however, cautioned that their tenure would not be excessively long, because the process for local government area elections would commence soon.
He warned against violence, stating that it is not his approach, urging the officials to sort out the salaries and entitlements of the outgoing chairmen.
