Eskom is struggling with its finances largely because of poor revenue collection but switching off defaulting municipalities is the utility's last resort.
Currently, 51 municipalities owe Eskom R3-billion. Municipalities in Mpumalanga, Free State and North West lead the bad payers.
The worst offender is the Free State's Matjhabeng municipality, which owes Eskom R337.8-million.
Mpumalanga' s Emalahleni owes R299.4-million. Matlosana, in North West, owes R105-million.
The Treasury has refused to help the utility pay its bills and the National Energy Regulator of SA granted it an electricity tariff increase lower than it asked for.
The SA Local Government Association said it would talk to Eskom to make sure that power to communities was not disrupted.
Eskom spokesman Khulu Phasiwe said it had sent disconnection notices to some of the defaulting municipalities, but "disconnection is a last resort".
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