Almost €3m is owed in unpaid commercial water rates to Dublin City Council.
As homeowners brace themselves for domestic water charges, business owners in the capital owe millions in overdue water bills.
A city council spokesman confirmed €1.7m is still owed by businesses for water supplies in 2013.
And a total of €1.2m remains outstanding in unpaid commercial water rates bills for previous years.
Commercial water charges due for the first nine months of this year total €8.2m, he said.
The city council, similar to other local authorities, act as an agent for Irish Water from January 1 this year.
The council is "pursuing" all commercial customers who are in arrears, the spokesman said.
"There is an active management policy in place and reminder letters are issued to customers advising of disconnection where arrears are outstanding.
"We engage fully with all customers to facilitate arrangements to discharge outstanding arrears," he said.
The council said that Irish Water is planning to "migrate" all information from the council's billing system next year when the State company will then "bill and collect".
Dublin Chamber of Commerce's Graeme McQueen told the Herald they would encourage mediation between businesses and the council about unpaid water charges.
"I think they need to come to some kind of agreement on payment terms and hopefully these parties can get around a table with each other and find a way to pay over a period of time perhaps," he said.
"We would certainly encourage discussion between the businesses and the council," he added.
Mr McQueen said that they have been lobbying to keep water rates on an even keel for businesses as there has been a focus on the domestic water charges.
"We have been calling for a long term freeze on water rates for some time because businesses have a lot of cost pressures on them," said Mr McQueen.
"Commercial rates and water rates put a lot of pressure on them so this is a fragile time," he added.