Onchan Commissioners say they can't provide an 'open chequebook' to fix issues at Groudle Glen.
The commissioners say they have, on a continued basis, considered the future of the wheelhouse and water wheel structure and claim it needs ‘significant structural work’.
In 2015 formal tenders showed the cost for complete restoration would be approximately ?200,000.
Chairman Martin Macfarlane said: "The Board have spent considerable time seeking a viable way forward to retain the attraction while remaining mindful that any expenditure must be in the best interest of the rate-payers of Onchan.
"The information available during the 2017/18 and 2018/19 budget setting process was a cost of approximately ?200,000 – a sum of that size would have an impact on rate-payers and was hard to justify against other priorities.”
In May last year the commissioners say they were made aware of an engineer who could supervise restoration on a voluntary basis – this is expected to cost around ?20,000.
Mr Macfarlane continued: "The recent voluntary proposal requires much more detail to fully understand and should not be taken at face value.
"There is a concern that, without further scrutiny, the proposed estimated costs could quite easily turn into an ‘open cheque-book’ which would certainly not be in the interests of the rate-payers of Onchan."
