The utilities regulator has given ECG and the Ghana Water Company a February 5 ultimatum to refund excess bills to customers following tariff increases last year.
The Public Utilities Regulatory Commission (PURC) has threatened to impose sanctions if the order is not strictly enforced.
PURC says it has come to its attention that Electricity Company of Ghana (ECG) and the Ghana Water Company Limited (GWCL) begun charging 59.2 and 67.2 percent respectively from December 1, 2015 instead of a December 14, 2015 timeline.
The PURC says if the utility providers fail to comply with the order by February 5 the ECG and the GWCL would automatically pay a surcharge of 5 percent of the excess amount over billed to each affected customer in addition to the refund.
These were contained in a letter Monday to the providers.
Commentators believe the letter is a face-saving move following revelation that the 59.2% electricity tariff imposed last year will shoot up to 75% due to the Energy Sector Levy.
The PURC ordered the utility service providers to charge additional costs to consumers as part of the levy.
The additional costs include a 5% rate for street light levy and another 5% levy for the national electrification charge, charged on consumers.
In addition, consumers pay a regular monthly service fee ranging from GHc6.33 to about GHc60 depending on the quantum of consumption and user classification.
The charges the PURC insists are in accordance with the recently introduced Energy Sector Levies Act 2015 (Act 899).