£15m in council tax and business rates debt written off in Wales
The 22 local authorities in Wales wrote-off £9.6m in business rates and £5.4m in council tax in the last financial year, BBC Wales has learned.
Cardiff council wrote off £1.6m in council tax compared with £594,254 in Swansea, £20,581 in Powys, £5,111 in Wrexham and £3,115 in Anglesey.
The councils insist "the vast majority of sums due are promptly collected".
Cardiff Council said less than 1% of money owed was written off and Swansea said the amount written off had fallen.
The information was obtained in a Freedom of Information request by BBC Wales' Newyddion Ar-lein .
In all, councils wrote-off over around 26,000 council tax debts and 3,000 business rate debts.
However, the latest figures have fallen steadily as Welsh authorities failed to collect more than £38m in council taxes alone in the financial year 2009-10.
Swansea saw the amount it wrote off in council tax arrears drop to £594,254 in 2011-12 compared with £1.7m in 2010-11 whereas business rates written off rose from £2.49m in 2010-11 to £2.52m in 2011-12.
A Cardiff Council spokesperson said it budgeted to collect over 98% of its council tax bill with the "target consistently met".
'Very small proportion'
He said the figure of £1.6m in council tax written off in 2011/12 represented less than 1% of the monies billed.
"As the capital city of Wales we are collecting 50% more than the next biggest council with the smallest only collecting 14% of our total," said the spokesperson.
He said during last year over £4m was collected from previous year's council tax arrears.
"Writing off a debt is always the last resort for the council, when all avenues have been explored including using tracing agents and insolvency action."
Swansea council said it followed a statutory recovery process, sending out reminders for overdue payments, as well as using the courts system.
During 2011/12, 14,772 accounts were summonsed for non payment of council tax and business rates and of those summonsed 8,267 had liability orders issued against them by Swansea Magistrates' Court, said the council.
It said it collects over £250m annually in rents, rates and council tax so, "whilst unwelcome, write-offs represent a very small proportion of income due to the council".
The TaxPayers' Alliance said that "councils in Wales need to explain why there is such a difference between their expected income and what they are actually managing to collect".
The Welsh Local Government Association, which represents councils, has said previously that collection rates in Wales were as good as anywhere.
Part of the reason for uncollected council tax was put down to a transient population and people who lost their jobs or their benefits.