Council have missed out on collecting over $291,000 of sewer usage charges after a manual audit uncovered an estimated 100 commercial property owners had not been charged, while hundreds of others have been paying since 2009.
The charge, which has been dubbed a "turd tax" on social media, was applied to non-residential properties using 20 mm copper sewage pipes in 2009, however due to "an administrative oversight or system error" at least 100 properties "have not been set up to receive the charge."
The issue came to light in recent weeks when property owners discovered a new charge on their quarterly water bill, without any qualification of what it was.
TRC director of corporate and governance Chris Weber said both the process responsible for properties not receiving the charge, and the subsequent lack of communication to those customers "is being investigated and reviewed."
"Non-residential users of this size supply are not in one location and are spread out - we have a rough estimate of 100 sites," he said.
"It looks like an administrative oversight on those properties and is being investigated.
"The minimum charge for that size is $291 a year - the sewer usage charge is levied per kilolitre of sewerage discharged to the sewerage system.
Council will not be charging fees retrospectively on those properties.
"We are reviewing the process, and correcting it for all future fees and charges," Mr Weber said.
"Our goal is to get our fees and charges correct in the revenue policy through regular audits.
"We are also looking at the lack of communication, and improving that in the future."