Life is a lottery for Queanbeyan ratepayers these days, with some receiving windfalls of $60,000 and others being slugged up to $93,000.

Queanbeyan Council is splashing the cash for 2054 property owners who will receive refunds from $15 to $61,000, following a property database audit.

But it is billing about 860 ratepayers, mostly small business owners, for unpaid rates going back to the 2009/10 financial year.

Outstanding charges total $3.7 million over five years.

Those ratepayers in the money are not saying much. Those hit with back-dated charges are saying plenty to the NSW Department of Fair Trading and their solicitors.

Surprised at a $9000 rate bill, coupled with his annual rates of about the same amount, PDA Marble and Granite principal Paul Tagliapietra said: ‘’I can’t believe you can do this in this day and age. I can’t go back to a customer and say sorry, I under-charged you five years ago.’’

John Res Mechanical Repairs spokeswoman Debbie Res said the 30-year-old business had been slugged $9900.

“It really doesn’t make sense to me. We had another client, he has a much, much bigger commercial property, yet his bill was much the same as ours.''

AT Joinery’s Allen Tzafaris said a letter from the council said it had conducted the most thorough audit ever and under the Local Government Act was required to correct anomalies.

Mr Tzafaris said he could not charge customers for unforseen costs five years ago, so why could the council?

"This is a crock. As far as I know, I have paid everything up to the last cent for every invoice they have sent me. I should not have to pay.’’

Queanbeyan Business Council vice president Steve Bartlett expects several of his properties to be billed.

“We can’t find out what the charges are for, we need more detail. They show us a spread sheet on how they are calculated, that means nothing. They need to please explain the adjustments.’’

Issuing a statement, a council spokesman said: "We are not willing to undertake any interview or make any further comment, unless required to clarify information.’’

Council's database of 16,800 properties has never been thoroughly audited until the one in question, according to the statement.

"Council apologises for this error and will be undertaking six-monthly audits of the property database from now on.

"The majority of ratepayers have been levied the correct rates and charges, and as a result they have been effectively subsidising the services for those who have been incorrectly charged.

The audit goes back five years to tie in with the elected term of councillors and new reporting framework.

“Ratepayers who have bought a new property during this time will only be charged back to the financial year after their property was purchased. For instance, if the property was purchased in January 2011, charges would only be levied from the 2011-12 financial year onwards.

 The majority of refunds apply to multi-unit dwellings. Residential properties incurred inaccuracies in waste charges.

The services included in the audit were water access, sewer access, sewer discharge, trade waste, storm water levy, water consumption and waste.