Lancashire County Council has raked in more than £500,000 in the last three years from overdue library charges.
And the figure would have been even higher, if the authority had not waived around 20% of the fees each year because of exemptions and if all offenders had paid up.
Since 2012, there have been almost 760,000 cases of overdue items, although the figure for this year so far of 180,680 is down 57%t on 2012.
Money collected in fines has also fallen. The total of fines paid this year has not been released, but last year’s figure of £161,845 compares to £177,344 in 2012 and £193.365 in 2011.
The authority said the fall is due to changes in the way the library system works.
Julie Bell, county library manager, said: “We have a vibrant library service here in Lancashire with more than 500,000 members, and over six million items were loaned last year.
“This includes ebooks and audio books which people can borrow online 24/7, with more than 10,000 titles to choose from.
“And, unlike traditional books, there is no need to remember to return ebooks. The file simply becomes inactive at the end of the loan period, meaning no more fines.
“In addition, library members can renew loans of physical books and other items online or by telephone, which is not only more convenient but makes it easier for people to avoid running up fines.
“It’s also important to remember the way people use libraries is changing. Our libraries are now modern community facilities that offer a wide range of services for local people of all ages.
“These include baby bounce and rhyme, job clubs, carers’ sessions and computer courses, alongside more traditional activities such as reading groups, which remain as popular as ever.”
In recent years the authority has been unable to recoup all fines, which include £2 per week on a DVD loan and 15p a day on books to a maximum of £6. In 2012, it managed 66% of all fines issues, and in 2013, 62%.
Ms Bell added: “Fines are not paid for a variety of reasons. We don’t follow up with further action, such as bailiffs, as it would cost more than we are likely to recover.”
The money raised goes back into the library service as part of the income the county council’s library service is required to raise each year.
The charges were last reviewed in 2012, and may be reviewed again next year to ensure they remain set at a reasonable level.
Lancashire-based storyteller Susan Allonby, who works in the county’s libraries, said: “I’m absolutely passionate about libraries and their value in the community.
“I don’t think overdue books present a problem; in fact a high number of overdues is probably an indicator of the popularity of the Library Service, reflecting, as it does, just a tiny percentage of total borrowing statistics, and, in these days of austerity and cuts, the fines collected could be very useful.
“A far greater threat to our libraries are the cuts just mentioned.”
Storyteller Simon Entwistle, from the Ribble Valley, is invited to LCC libraries regularly.
He said: “I am very surprised at the amount of fines given out. Today’s youth are perhaps not as concerned as past generations with regards library fines.”
He added: “I am not familiar with the fine system, but I do know libraries are under a huge amount of pressure to keep going with lack of funding. So I should imagine any income is a huge help.”