The amount -- €2,073,500 -- has been labelled by Dublin City Council as "uncollectable" and written off as bad debt.
It is part of an overall €11.2m owed to the council by Dublin householders.
A further €2.7m was collected by waste company Greyhound on behalf of the council between May and December last year.
The council is now intending to take legal action to recover €9.1m. The council transferred responsibility for collecting €14m in outstanding waste charges to Greyhound last May.
However, it was forced to write off 20pc of this amount (€2,073,500) shortly afterwards when attempts to recover the money failed.
Greyhound hired a debt collection company to contact householders asking for the cash. As of December 16 last year, €2,745,000 had been successfully collected.
Greyhound took over the council's bin service in January last year.
As part of the deal, the company agreed to collect waste fees which had been accumulated by Dublin households during the last three months of 2011. But the debt collection element of the arrangement was referred to the Data Protection Commissioner following a Fianna Fail council motion.
But the commissioner found no transfer of personal data from the council to Greyhound about the collection of debts had taken place, a fact confirmed during an unannounced inspection at the company's premises.
Agreement was reached between Greyhound and the commissioner on requirements to allow the issuing of the payment demands.
The data office said it was satisfied with both the contractual arrangements and the practical arrangements.
Within days of the commissioner's ruling, Dublin residents who owed bin charges had bills issued to them.
After the council imposed bin charges more than a decade ago, thousands of households throughout the city refused to pay. The anti-bin tax campaign continued until the council transferred the service to Greyhound, leading to the accumulation of significant legacy debt.