A late November investigation by the state Department of Environmental Protection found that the Steelton Water Authority did not adequately disinfect for giardia and didn't record turbidity, or the cloudiness levels of the water.
Borough officials say they fired the plant's chief operator in March after six years on the job. The water authority was not required to send a notice to customers back in November because the required steps were taken to correct the giardia issue.
The borough says the water is safe and the DEP has been conducting weekly site visits to the plant.
The Water Authority is operating on a $2.7 million budget, and it has to pay a $55,000 fine, but residents will not see an increase on their bills.