Saltdean Lido has lost £250,000 in the past five years, its owner said
An outdoor swimming baths in East Sussex could be closed and turned into an apartment block.
Dennis Audley, owner of the Grade II-listed Saltdean Lido, said it had lost more than £250,000 over five years due to a succession of poor summers.
He said he wanted to create an all-year leisure facility for the community.
Brighton and Hove City Council said it had not received a planning application but would work to protect the appearance of the 1930s building.
Mr Audley said: "I've owned it for the last 10 years and in the first five we would take £60,000, but over the last three years we haven't exceeded £4,000 so unfortunately we've built up an enormous loss.
'No planning application'
He added: "We have no intention of knocking the building down and want to increase the leisure activities on the site which the locals can use all year round."
The proposals would see the pool removed but new facilities built, including a library.
A public meeting has been held for residents to view the plans.
A spokesman for Brighton and Hove Council said: "We've had no planning application so there's nothing to have a view on thus far.
"But it's a listed building and all councils are protective of such buildings."