The paddling pool at Central Park in Park Road has been closed.
Peterborough City Council said: "Contractors are working to fix the problem as soon as possible. We will advise once we are able to reopen. Apologies for any inconvenience."
Asked by the Peterborough Telegraph what the issue is, a council spokesman said: "There is a problem with the pool's chemical dosing system and we are currently awaiting delivery of new parts for this. We will aim to get the issue resolved and the pool re-opened as soon as possible."