Money saving expert Martin Lewis has revealed everyone who has moved house since 1993 could be owed money as overpaid council tax.
What did Martin Lewis say?
Founder of MoneySavingExpert, Martin Lewis, said: "Councils are sitting on a staggering amount of money, at least £230million spread across 1.7 million accounts, which works out at an average of well over £100 sitting in each closed account.
"And while councils do make efforts to track down those who are owed, many don't do it well enough, especially when people have moved out of their area and are no longer their responsibility.
"That means we all need to take responsibility for ourselves.”
Owners of these 1.7 million council tax accounts should have been refunded when the account was closed, but Lewis noted that savers are not encouraged to call up their council.
He suggested taking a few other steps first, including reading the Money Saving Expert guide.
The credit in the council tax accounts accumulates as households pay council tax a month or a year in advance, meaning it's common to have leftover credit when moving house.
The report noted anyone who has moved homes since 1993 should check if they are due over £100 because of the overpayments and credit.
Credit is also added if someone overpays their council tax bill, if a resident has moved out or if someone living in the property died.
Then those credits should be refunded automatically before the account is closed.
Who could be owed money?
Researchers believe households are most likely able to claim if they've moved out of a council or local authority in the last 29 years and was not paying council tax via direct debit.
Households that did not leave a forwarding address when they moved are even more likely to be owed a refund.
How to check if you are due a refund
The simplest and quickest way to check and claim is via an online form from your old council.
Searching the council name and "council tax refund form" online should lead you to the correct document if available.
Another way is by going on the GOV.UK website and email, or live chatting or even by calling the council.
Members of the investigations attempted calling their old councils to see the process and most were only asked for their name and old address, whilst some others had to go through some security questions.
However, the report noted the process was "usually straightforward".