Hove Lagoon is starting to drain after the pump that maintains the water levels failed.
But four months on, delays in sourcing a vital replacement part costing about £5,000 have landed Brighton and Hove City Council with a bill approaching £50,000.
The contractor Sykes, which is responsible for repairing the pump, rented a temporary pump to the council for 20 weeks at £2,000 a week.
But the council has put a halt to the growing bill, which also included fuel for the temporary pump.
Sykes has told the council this week that the pump cannot be repaired. The company said that it was putting together options for temporary and permanent solutions.
Now the water has begun to drain away, with businesses affected, particularly in the smaller lake.
The council said: “The temporary pump – which was put in place to keep the Lagoon filled over the summer – is currently being removed.
“We are working with the pump suppliers and Hove Lagoon Watersports to ensure the existing pump is repaired as quickly as possible so the Lagoon can be refilled ready for the start of the new season in the spring.”
Councillors Robert Nemeth and Garry Peltzer Dunn, who represent Wish ward, have inspected the pump site which is in their ward.
Councillor Nemeth said: “It’s a relief that the council’s Seafront Office put emergency measures in place to ensure that Hove’s premier seafront attraction could actually function over the summer months but a huge disappointment that Sykes has not yet actually repaired what has been broken since June.
“Councillor Peltzer Dunn and I just can’t understand how a specialist pump company can take nearly five months to conclude that they cannot repair a single basic pump. Where does that leave users of the Lagoon now?
“The irony is that they have also been hiring temporary pumps to the council at a cost many times that of the unfinished repair.
“The honourable thing to do now would be to refund the astronomical pump hire charge and sort out the situation sharpish.”