The Surfers Against Sewage sewage alert system has warned of raw sewage entering the sea off Gyllyngvase beach today.
However South West Water have said they think the warning may have been triggered by a malfunction.
South West Water has said that they believe there has been no discharge, and that it has sent staff to check the event duration monitor at the site.
The company added it will update its Beach Live website, which had been warning of the spill with any further information. It has now been changed to, "the monitors at this bathing water are currently undergoing maintenance".
The company was asked what they would advice would they give to families enjoying the water at the busy beach today, however said it was not in a position give any advice.
The warning that an overflow has occurred which may be affecting bathing water quality came from the SAS Sewage Alert Service, a national service to inform people, in real time, when untreated human sewage and wastewater is being discharged at a beach.
This information is aimed at allowing water users to make an informed decision about how, when and where you use the sea.
Untreated sewage and wastewater can discharge from combined sewer overflows (CSOs) , normally after heavy rain, sometimes significantly reducing water quality.
When this reaches dangerous levels, SAS is notified by participating water companies and issues a real-time sewage alert so surfers and other beach users can avoid this potentially harmful pollution incident.
SAS’s free Sewage Alert Service, available as an App, SMS service or web-based map, issues these warnings for 260 popular UK beaches.